/* ========================================================
   NEON GARDEN — Design System
   English Learning App UI/UX Redesign
   ======================================================== */

/* ===== CSS Custom Properties ===== */
:root {
    /* Backgrounds */
    --bg: #FAFBFE;
    --bg-card: #FFFFFF;
    --bg-card-hover: #F5F7FF;
    --bg-sunken: #F0F2F8;
    --bg-overlay: rgba(15, 23, 42, 0.4);

    /* Text */
    --text-primary: #1B1F3B;
    --text-secondary: #5C6180;
    --text-muted: #9298B8;
    --text-inverse: #FFFFFF;

    /* Brand Accent */
    --accent: #6C5CE7;
    --accent-light: #A29BFE;
    --accent-bg: #EDE8FF;
    --accent-glow: rgba(108, 92, 231, 0.25);

    /* Module Colors */
    --mod-vocab: #6C5CE7;
    --mod-vocab-bg: #EDE8FF;
    --mod-vocab-glow: rgba(108, 92, 231, 0.2);
    --mod-tenses: #E17055;
    --mod-tenses-bg: #FDEAE5;
    --mod-tenses-glow: rgba(225, 112, 85, 0.2);
    --mod-phrases: #FD79A8;
    --mod-phrases-bg: #FFE8F0;
    --mod-phrases-glow: rgba(253, 121, 168, 0.2);
    --mod-games: #A29BFE;
    --mod-games-bg: #EEEAFF;
    --mod-games-glow: rgba(162, 155, 254, 0.2);
    --mod-stats: #00B894;
    --mod-stats-bg: #E0F9F1;
    --mod-stats-glow: rgba(0, 184, 148, 0.2);

    /* Semantic */
    --correct: #00B894;
    --correct-bg: #E0F9F1;
    --correct-border: #55EFC4;
    --correct-glow: rgba(0, 184, 148, 0.3);
    --wrong: #FF6B6B;
    --wrong-bg: #FFE8E8;
    --wrong-border: #FF8E8E;
    --wrong-glow: rgba(255, 107, 107, 0.3);
    --warning: #FDCB6E;
    --warning-bg: #FFF8E7;
    --info: #74B9FF;
    --info-bg: #E8F4FF;

    /* Borders */
    --border: #E8EAF2;
    --border-strong: #B8BDD4;

    /* Shadows — glow-based */
    --shadow-sm: 0 1px 3px rgba(27, 31, 59, 0.04), 0 1px 2px rgba(27, 31, 59, 0.06);
    --shadow-md: 0 4px 12px rgba(27, 31, 59, 0.06), 0 2px 4px rgba(27, 31, 59, 0.04);
    --shadow-lg: 0 12px 32px rgba(27, 31, 59, 0.08), 0 4px 8px rgba(27, 31, 59, 0.04);
    --shadow-xl: 0 20px 50px rgba(27, 31, 59, 0.12);
    --shadow-glow: 0 0 20px rgba(108, 92, 231, 0.15), 0 0 60px rgba(108, 92, 231, 0.05);

    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #6C5CE7 0%, #A29BFE 100%);
    --gradient-accent: linear-gradient(135deg, #6C5CE7, #FD79A8);
    --gradient-warm: linear-gradient(135deg, #E17055, #FDCB6E);
    --gradient-cool: linear-gradient(135deg, #00B894, #74B9FF);
    --gradient-pink: linear-gradient(135deg, #FD79A8, #A29BFE);

    /* Radii — organic system */
    --radius: 14px;
    --radius-sm: 8px;
    --radius-lg: 20px;
    --radius-xl: 28px;
    --radius-full: 9999px;
    --radius-organic: 20px 24px 20px 16px;

    /* Transitions */
    --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
    --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
    --duration-fast: 150ms;
    --duration-normal: 250ms;
    --duration-slow: 400ms;
    --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);

    /* Typography */
    --font-primary: 'Nunito', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-english: 'JetBrains Mono', 'Fira Code', 'SF Mono', monospace;
}

/* ===== Dark Mode ===== */
body.dark {
    --bg: #0D0F1A;
    --bg-card: #171A2E;
    --bg-card-hover: #1E2242;
    --bg-sunken: #0A0C16;
    --bg-overlay: rgba(0, 0, 0, 0.6);

    --text-primary: #E8EAF6;
    --text-secondary: #8F95B2;
    --text-muted: #5C6180;
    --text-inverse: #FFFFFF;

    --accent: #A29BFE;
    --accent-light: #B4AFFE;
    --accent-bg: #1E1A3A;
    --accent-glow: rgba(162, 155, 254, 0.2);

    --mod-vocab: #A29BFE;
    --mod-vocab-bg: #1E1A3A;
    --mod-tenses: #FAB1A0;
    --mod-tenses-bg: #2A1A16;
    --mod-phrases: #FF9FF3;
    --mod-phrases-bg: #2A1528;
    --mod-games: #C8B6FF;
    --mod-games-bg: #1E1A3A;
    --mod-stats: #55EFC4;
    --mod-stats-bg: #0A2A22;

    --correct: #55EFC4;
    --correct-bg: #0A2A22;
    --correct-border: #00B894;
    --correct-glow: rgba(85, 239, 196, 0.2);
    --wrong: #FF8E8E;
    --wrong-bg: #2A1414;
    --wrong-border: #FF6B6B;
    --wrong-glow: rgba(255, 142, 142, 0.2);
    --warning: #FFEAA7;
    --warning-bg: #2A2410;
    --info: #A0D2FF;
    --info-bg: #101A2A;

    --border: #1E2242;
    --border-strong: #3A3E5A;

    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.2);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 12px 32px rgba(0, 0, 0, 0.4);
    --shadow-xl: 0 20px 50px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 20px rgba(162, 155, 254, 0.12), 0 0 60px rgba(162, 155, 254, 0.04);
}

/* ===== Reset & Base ===== */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: var(--font-primary);
    background: var(--bg);
    color: var(--text-primary);
    min-height: 100vh;
    min-height: 100dvh;
    transition: background var(--transition), color var(--transition);
    -webkit-font-smoothing: antialiased;
    font-weight: 500;
    font-size: 1rem;
    line-height: 1.5;
}

/* Aurora Background */
body::before {
    content: '';
    position: fixed;
    inset: 0;
    background:
        radial-gradient(ellipse at 10% 0%, rgba(108, 92, 231, 0.05) 0%, transparent 50%),
        radial-gradient(ellipse at 90% 100%, rgba(253, 121, 168, 0.04) 0%, transparent 50%),
        radial-gradient(ellipse at 50% 50%, rgba(0, 184, 148, 0.02) 0%, transparent 60%);
    pointer-events: none;
    z-index: 0;
}

body.dark::before {
    background:
        radial-gradient(ellipse at 10% 0%, rgba(162, 155, 254, 0.06) 0%, transparent 50%),
        radial-gradient(ellipse at 90% 100%, rgba(255, 159, 243, 0.04) 0%, transparent 50%),
        radial-gradient(ellipse at 50% 50%, rgba(85, 239, 196, 0.03) 0%, transparent 60%);
}

/* ===== App Shell ===== */
.app-shell {
    position: relative;
    z-index: 1;
    min-height: 100vh;
    min-height: 100dvh;
}

/* ===== Sidebar (Desktop only) ===== */
.sidebar {
    display: none;
}

@media (min-width: 1024px) {
    .app-shell {
        display: grid;
        grid-template-columns: 260px 1fr;
    }
    .sidebar {
        display: flex;
        flex-direction: column;
        position: sticky;
        top: 0;
        height: 100vh;
        overflow-y: auto;
        border-right: 1px solid var(--border);
        background: var(--bg-card);
        padding: 1.5rem 1rem;
        z-index: 10;
        transition: background var(--transition), border-color var(--transition);
    }
    .main-content {
        min-height: 100vh;
        font-size: 16px;
    }
}

.sidebar-brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0 0.5rem 1.25rem;
    border-bottom: 1px solid var(--border);
    margin-bottom: 1.25rem;
}

.sidebar-logo {
    font-family: var(--font-english);
    font-size: 1.5rem;
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.sidebar-tagline {
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--text-secondary);
}

.sidebar-user-stats {
    padding: 0 0.5rem 1rem;
}

.sidebar-streak {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.5rem 0.75rem;
    background: var(--warning-bg);
    border-radius: var(--radius-full);
    font-size: 0.85rem;
    font-weight: 700;
    width: fit-content;
}

.streak-flame {
    font-size: 1.1rem;
    animation: streakPulse 2s ease-in-out infinite;
}

@keyframes streakPulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.1) rotate(3deg); }
}

.streak-count {
    color: var(--text-primary);
}

.streak-label {
    color: var(--text-muted);
    font-weight: 600;
}

.sidebar-nav {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.sidebar-nav-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.7rem 0.75rem;
    border: none;
    background: transparent;
    border-radius: var(--radius);
    cursor: pointer;
    font-family: var(--font-primary);
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-secondary);
    transition: all var(--duration-fast) ease;
    text-align: left;
    width: 100%;
    position: relative;
}

.sidebar-nav-item:hover {
    background: var(--bg-sunken);
    color: var(--text-primary);
}

.sidebar-nav-item.active {
    background: var(--accent-bg);
    color: var(--accent);
    font-weight: 700;
}

.sidebar-nav-item.active::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 3px;
    height: 60%;
    background: var(--accent);
    border-radius: 0 4px 4px 0;
}

.nav-icon {
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    font-weight: 800;
}

.nav-label {
    white-space: nowrap;
}

.sidebar-footer {
    padding-top: 1rem;
    border-top: 1px solid var(--border);
    margin-top: 0.5rem;
}

.sidebar-dark-toggle {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    cursor: pointer;
    font-size: 0.85rem;
    color: var(--text-secondary);
    padding: 0.5rem;
}

.sidebar-dark-toggle .toggle-slider {
    width: 44px;
    height: 24px;
    background: var(--border);
    border-radius: var(--radius-full);
    position: relative;
    transition: background var(--duration-normal);
    flex-shrink: 0;
}

.sidebar-dark-toggle .toggle-slider::after {
    content: '';
    position: absolute;
    top: 3px;
    left: 3px;
    width: 18px;
    height: 18px;
    background: white;
    border-radius: 50%;
    transition: transform var(--duration-normal) var(--ease-spring);
    box-shadow: 0 1px 3px rgba(0,0,0,0.15);
}

.sidebar-dark-toggle input:checked + .toggle-slider {
    background: var(--gradient-primary);
}

.sidebar-dark-toggle input:checked + .toggle-slider::after {
    transform: translateX(20px);
}

.sidebar-dark-toggle input {
    display: none;
}

/* ===== Screens ===== */
.screen {
    display: none;
    min-height: 100vh;
    min-height: 100dvh;
    animation: screenEnter 0.4s var(--ease-out);
}

.screen.active {
    display: flex;
    flex-direction: column;
}

@keyframes screenEnter {
    from { opacity: 0; transform: translateY(16px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeSlideIn {
    from { opacity: 0; transform: translateY(16px); }
    to { opacity: 1; transform: translateY(0); }
}

/* ===== Start Container (shared) ===== */
.start-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 2rem 1.25rem;
    max-width: 520px;
    width: 100%;
    margin: 0 auto;
    gap: 1rem;
}

/* ===== Home Screen ===== */
.logo-icon {
    font-size: 3rem;
    animation: floatBounce 3s ease-in-out infinite;
    margin-bottom: 0.25rem;
}

@keyframes floatBounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-8px); }
}

h1 {
    font-family: var(--font-english);
    font-size: 2rem;
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.02em;
    line-height: 1.2;
}

.subtitle {
    font-size: 0.9rem;
    color: var(--text-secondary);
    font-weight: 600;
    text-align: center;
}

/* Module Grid — 2×2 on mobile */
.module-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
    width: 100%;
    margin-top: 0.5rem;
}

/* ===== Module Card ===== */
.module-card {
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    padding: 1.5rem 1rem 1.25rem;
    background: var(--bg-card);
    border: 2px solid var(--border);
    border-radius: var(--radius-organic);
    cursor: pointer;
    transition: all var(--duration-normal) var(--ease-out);
    box-shadow: var(--shadow-sm);
    font-family: var(--font-primary);
    gap: 0.5rem;
    overflow: hidden;
}

.module-card::before {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--gradient-primary);
    opacity: 0.6;
    transition: opacity var(--duration-fast);
}

#module-vocab-btn::before { background: linear-gradient(90deg, #6C5CE7, #A29BFE); }
#module-tenses-btn::before { background: linear-gradient(90deg, #E17055, #FDCB6E); }
#module-phrases-btn::before { background: linear-gradient(90deg, #FD79A8, #A29BFE); }
#module-game-btn::before { background: linear-gradient(90deg, #A29BFE, #C8B6FF); }
#module-stats-btn::before { background: linear-gradient(90deg, #00B894, #55EFC4); }

.module-card:hover {
    border-color: var(--accent);
    transform: translateY(-3px);
    box-shadow: var(--shadow-md), 0 0 20px var(--mod-vocab-glow);
}

#module-vocab-btn:hover { box-shadow: var(--shadow-md), 0 0 20px var(--mod-vocab-glow); }
#module-tenses-btn:hover { box-shadow: var(--shadow-md), 0 0 20px var(--mod-tenses-glow); border-color: var(--mod-tenses); }
#module-phrases-btn:hover { box-shadow: var(--shadow-md), 0 0 20px var(--mod-phrases-glow); border-color: var(--mod-phrases); }
#module-game-btn:hover { box-shadow: var(--shadow-md), 0 0 20px var(--mod-games-glow); border-color: var(--mod-games); }

.module-card:active {
    transform: scale(0.97);
}

/* Stats card — full width below grid */
#module-stats-btn {
    grid-column: 1 / -1;
    flex-direction: row;
    text-align: left;
    padding: 1rem 1.25rem;
}

#module-stats-btn:hover {
    box-shadow: var(--shadow-md), 0 0 20px var(--mod-stats-glow);
    border-color: var(--mod-stats);
}

#module-stats-btn .module-icon {
    font-size: 1.5rem;
    width: 40px;
    height: 40px;
}

.module-icon {
    width: 56px;
    height: 56px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.75rem;
    font-weight: 800;
    font-family: var(--font-english);
    border-radius: var(--radius);
    background: var(--accent-bg);
    color: var(--accent);
    flex-shrink: 0;
}

#module-tenses-btn .module-icon { background: var(--mod-tenses-bg); color: var(--mod-tenses); }
#module-phrases-btn .module-icon { background: var(--mod-phrases-bg); color: var(--mod-phrases); font-family: var(--font-primary); }
#module-game-btn .module-icon { background: var(--mod-games-bg); color: var(--mod-games); font-family: var(--font-primary); }
#module-stats-btn .module-icon { background: var(--mod-stats-bg); color: var(--mod-stats); font-family: var(--font-primary); }

.module-info {
    flex: 1;
    min-width: 0;
}

.module-title {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1.3;
}

.module-desc {
    font-size: 0.8rem;
    color: var(--text-muted);
    font-weight: 500;
    margin-top: 0.15rem;
    line-height: 1.3;
}

.module-progress-bar-wrap {
    width: 100%;
    height: 6px;
    background: var(--bg-sunken);
    border-radius: var(--radius-full);
    overflow: hidden;
    margin-top: 0.5rem;
}

.module-progress-bar {
    height: 100%;
    border-radius: var(--radius-full);
    background: var(--gradient-primary);
    transition: width 0.6s var(--ease-out);
    position: relative;
}

/* Shimmer on progress bar */
.module-progress-bar::after {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
    animation: shimmer 2.5s ease-in-out infinite;
}

@keyframes shimmer {
    from { transform: translateX(-100%); }
    to { transform: translateX(100%); }
}

.module-stat {
    font-size: 0.78rem;
    color: var(--text-muted);
    font-weight: 600;
    margin-top: 0.25rem;
}

/* Settings toggle */
.start-options {
    width: 100%;
    display: flex;
    justify-content: center;
    margin-top: 0.5rem;
}

.toggle-option {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
    user-select: none;
    font-size: 0.85rem;
    color: var(--text-secondary);
    font-weight: 600;
}

.toggle-option input {
    display: none;
}

.toggle-slider {
    width: 44px;
    height: 24px;
    background: var(--border);
    border-radius: var(--radius-full);
    position: relative;
    transition: background var(--duration-normal);
    flex-shrink: 0;
}

.toggle-slider::after {
    content: '';
    position: absolute;
    top: 3px;
    left: 3px;
    width: 18px;
    height: 18px;
    background: white;
    border-radius: 50%;
    transition: transform var(--duration-normal) var(--ease-spring);
    box-shadow: 0 1px 3px rgba(0,0,0,0.15);
}

.toggle-option input:checked + .toggle-slider {
    background: var(--gradient-primary);
}

.toggle-option input:checked + .toggle-slider::after {
    transform: translateX(20px);
}

.toggle-text {
    font-weight: 600;
}

h2 {
    font-size: 1.25rem;
    font-weight: 800;
    line-height: 1.2;
}

/* ===== Start Stats ===== */
.start-stats {
    display: flex;
    gap: 0.75rem;
    width: 100%;
    justify-content: center;
}

.stat-item {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 0.75rem 0.5rem;
    background: var(--bg-card);
    border: 1.5px solid var(--border);
    border-radius: var(--radius);
    transition: all var(--duration-fast);
}

.stat-number {
    font-family: var(--font-english);
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--accent);
}

.stat-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-top: 0.15rem;
}

/* ===== Buttons ===== */
.btn-primary {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-primary);
    color: var(--text-inverse);
    border: none;
    border-bottom: 4px solid rgba(0,0,0,0.15);
    border-radius: var(--radius);
    padding: 0.875rem 1.75rem;
    font-family: var(--font-primary);
    font-size: 0.95rem;
    font-weight: 700;
    cursor: pointer;
    transition: transform var(--duration-fast) var(--ease-spring),
                box-shadow var(--duration-normal) var(--ease-out),
                border-bottom-width var(--duration-fast);
    box-shadow: 0 4px 16px var(--accent-glow);
    position: relative;
    overflow: hidden;
}

.btn-primary::after {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
    transition: left 0.6s var(--ease-out);
}

.btn-primary:hover:not(:disabled)::after {
    left: 100%;
}

.btn-primary:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 8px 24px var(--accent-glow);
}

.btn-primary:active:not(:disabled) {
    border-bottom-width: 1px;
    transform: translateY(3px);
}

.btn-primary:disabled {
    opacity: 0.4;
    cursor: not-allowed;
    box-shadow: none;
}

.btn-large {
    width: 100%;
    padding: 1rem;
}

.btn-secondary {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: transparent;
    color: var(--text-secondary);
    border: 2px solid var(--border);
    border-radius: var(--radius);
    padding: 0.75rem 1.5rem;
    font-family: var(--font-primary);
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--duration-fast);
    width: 100%;
}

.btn-secondary:hover:not(:disabled) {
    border-color: var(--accent);
    color: var(--accent);
    background: var(--accent-bg);
}

.btn-secondary:active:not(:disabled) {
    transform: scale(0.98);
}

.btn-secondary:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

.btn-outline {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.4rem;
    background: transparent;
    color: var(--text-secondary);
    border: 1.5px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 0.5rem 1rem;
    font-family: var(--font-primary);
    font-size: 0.85rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--duration-fast);
}

.btn-outline:hover:not(:disabled) {
    border-color: var(--accent);
    color: var(--accent);
}

.btn-outline:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

/* ===== Top Bar ===== */
.top-bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem 1rem;
    gap: 0.5rem;
    position: sticky;
    top: 0;
    z-index: 5;
    background: var(--bg);
    transition: background var(--transition);
}

.top-bar-title {
    font-size: 1rem;
    font-weight: 700;
    color: var(--text-primary);
    flex: 1;
    text-align: center;
}

.icon-btn {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 2px solid var(--border);
    border-radius: 50%;
    background: var(--bg-card);
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--duration-fast);
    flex-shrink: 0;
}

.icon-btn:hover {
    border-color: var(--accent);
    color: var(--accent);
    background: var(--accent-bg);
}

.icon-btn:active {
    transform: scale(0.95);
}

/* Score Badge */
.score-badge {
    display: flex;
    align-items: center;
    gap: 0.35rem;
    padding: 0.35rem 0.75rem;
    border-radius: var(--radius-full);
    background: var(--bg-card);
    border: 1.5px solid var(--border);
    font-size: 0.85rem;
    font-weight: 700;
    font-family: var(--font-english);
}

.correct-count { color: var(--correct); }
.wrong-count { color: var(--wrong); }
.score-sep { color: var(--text-muted); font-size: 0.75rem; }

/* ===== Progress Bar ===== */
.progress-bar-container {
    width: 100%;
    height: 6px;
    background: var(--bg-sunken);
    border-radius: var(--radius-full);
    overflow: hidden;
    margin-bottom: 0.5rem;
}

.progress-bar {
    height: 100%;
    border-radius: var(--radius-full);
    background: var(--gradient-primary);
    transition: width 0.6s var(--ease-out);
    position: relative;
}

.progress-bar::after {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
    animation: shimmer 2.5s ease-in-out infinite;
}

.progress-info {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-secondary);
    font-family: var(--font-english);
}

/* ===== Word Card ===== */
.word-card {
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 1.75rem 1.5rem;
    background: var(--bg-card);
    border: 2px solid var(--border);
    border-radius: var(--radius-xl);
    margin: 0.5rem 1rem;
    transition: all var(--duration-normal);
    box-shadow: var(--shadow-md);
}

/* Halo effect behind word card */
.word-card::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 120%;
    height: 120%;
    background: radial-gradient(circle, var(--accent-glow) 0%, transparent 70%);
    border-radius: 50%;
    z-index: -1;
    opacity: 0.5;
    transition: opacity var(--duration-normal);
}

.word-card.correct-highlight {
    border-color: var(--correct);
    box-shadow: 0 0 20px var(--correct-glow);
}

.word-card.wrong-highlight {
    border-color: var(--wrong);
    animation: cardShake 0.3s ease;
}

@keyframes cardShake {
    0%, 100% { transform: translateX(0); }
    20% { transform: translateX(-6px); }
    40% { transform: translateX(6px); }
    60% { transform: translateX(-4px); }
    80% { transform: translateX(2px); }
}

.word-label {
    font-size: 0.72rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-muted);
    margin-bottom: 0.5rem;
}

.word-text {
    font-family: var(--font-english);
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--text-primary);
    text-align: center;
    line-height: 1.3;
}

.word-phonetic {
    font-family: var(--font-english);
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--accent);
    margin-top: 0.25rem;
}

.word-info {
    font-size: 0.8rem;
    color: var(--text-muted);
    font-weight: 600;
    font-style: italic;
    margin-top: 0.25rem;
}

.word-btn-row {
    display: flex;
    gap: 0.75rem;
    margin-top: 0.75rem;
}

.speak-btn, .mic-btn {
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 2px solid var(--border);
    border-radius: 50%;
    background: var(--bg-card);
    color: var(--accent);
    cursor: pointer;
    transition: all var(--duration-fast);
}

.speak-btn:hover, .mic-btn:hover {
    background: var(--accent-bg);
    border-color: var(--accent);
    transform: scale(1.05);
}

.speak-btn:active, .mic-btn:active {
    transform: scale(0.95);
}

.speech-result {
    margin-top: 0.5rem;
    font-size: 0.85rem;
    font-weight: 600;
    padding: 0.4rem 0.75rem;
    border-radius: var(--radius-sm);
    background: var(--bg-sunken);
}

/* ===== IV Badge (Irregular Verb) ===== */
.iv-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    padding: 0.3rem 0.65rem;
    background: linear-gradient(135deg, #FDCB6E, #E17055);
    color: #fff;
    border: none;
    border-radius: var(--radius-full);
    font-size: 0.75rem;
    font-weight: 700;
    cursor: pointer;
    margin-top: 0.5rem;
    animation: badgePulse 2s ease-in-out infinite;
    transition: transform var(--duration-fast);
}

.iv-badge:hover {
    transform: scale(1.05);
}

@keyframes badgePulse {
    0%, 100% { box-shadow: 0 0 0 0 rgba(253, 203, 110, 0.4); }
    50% { box-shadow: 0 0 0 6px rgba(253, 203, 110, 0); }
}

/* ===== Feedback ===== */
.feedback {
    min-height: 1.75rem;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.9rem;
    font-weight: 700;
    padding: 0 1rem;
    text-align: center;
    transition: all var(--duration-fast);
}

.feedback.correct-feedback {
    color: var(--correct);
}

.feedback.wrong-feedback {
    color: var(--wrong);
}

.feedback.checking {
    color: var(--text-secondary);
    animation: pulse-check 1s ease-in-out infinite;
}

@keyframes pulse-check {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

/* ===== Options Grid ===== */
.options-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.6rem;
    padding: 0 1rem;
    margin-bottom: 0.75rem;
}

.option-btn {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 0.9rem 0.75rem 0.9rem 2.25rem;
    background: var(--bg-card);
    border: 2.5px solid var(--border);
    border-bottom: 4px solid color-mix(in srgb, var(--border) 80%, black 20%);
    border-radius: 16px;
    font-family: var(--font-primary);
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-primary);
    cursor: pointer;
    transition: all var(--duration-fast) var(--ease-spring);
    min-height: 60px;
    line-height: 1.3;
    word-break: break-word;
}

/* Letter badge (A, B, C, D) */
.option-btn::before {
    content: attr(data-label);
    position: absolute;
    left: 8px;
    top: 50%;
    transform: translateY(-50%);
    width: 26px;
    height: 26px;
    border-radius: 50%;
    background: var(--bg-sunken);
    color: var(--text-muted);
    font-size: 0.72rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    justify-content: center;
}

.option-btn:hover:not(:disabled):not(.correct):not(.wrong) {
    border-color: var(--accent);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md), 0 0 0 3px var(--accent-glow);
}

.option-btn:active:not(:disabled) {
    border-bottom-width: 2px;
    transform: translateY(2px);
}

.option-btn.correct {
    border-color: var(--correct);
    background: var(--correct-bg);
    color: var(--correct);
    box-shadow: 0 0 0 3px var(--correct-glow);
    animation: optionPop 350ms var(--ease-spring);
}

.option-btn.correct::before {
    background: var(--correct);
    color: white;
    content: '✓';
}

.option-btn.wrong {
    border-color: var(--wrong);
    background: var(--wrong-bg);
    color: var(--wrong);
    animation: optionShake 300ms ease;
}

.option-btn.wrong::before {
    background: var(--wrong);
    color: white;
    content: '✗';
}

.option-btn:disabled {
    cursor: default;
    opacity: 0.6;
}

@keyframes optionPop {
    0% { transform: scale(1); }
    50% { transform: scale(1.04); }
    100% { transform: scale(1); }
}

@keyframes optionShake {
    0%, 100% { transform: translateX(0); }
    20% { transform: translateX(-5px); }
    40% { transform: translateX(5px); }
    60% { transform: translateX(-3px); }
    80% { transform: translateX(2px); }
}

/* Next button in quiz */
#next-btn, #review-next-btn, #practice-next-btn, #phrases-next-btn {
    margin: 0 1rem 1rem;
    width: calc(100% - 2rem);
}

/* ===== Quiz Container ===== */
.quiz-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    max-width: 600px;
    width: 100%;
    margin: 0 auto;
}

/* ===== Level Filter Pills ===== */
.phrases-level-filter, .story-level-filter {
    display: flex;
    gap: 0.4rem;
    overflow-x: auto;
    padding: 0.25rem 0;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
}

.phrases-level-filter::-webkit-scrollbar,
.story-level-filter::-webkit-scrollbar {
    display: none;
}

.level-pill {
    padding: 0.4rem 1rem;
    border: 2px solid var(--border);
    border-radius: var(--radius-full);
    background: transparent;
    font-family: var(--font-primary);
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--duration-fast);
    white-space: nowrap;
    flex-shrink: 0;
}

.level-pill:hover {
    border-color: var(--accent);
    color: var(--accent);
}

.level-pill.active {
    background: var(--accent);
    border-color: var(--accent);
    color: var(--text-inverse);
}

/* Level-specific active colors */
.level-pill.active[data-level="A1"] { background: var(--correct); border-color: var(--correct); }
.level-pill.active[data-level="A2"] { background: var(--info); border-color: var(--info); }
.level-pill.active[data-level="B1"] { background: #D97706; border-color: #D97706; }
.level-pill.active[data-level="B2"] { background: var(--wrong); border-color: var(--wrong); }

/* ===== Result Screens ===== */
.result-icon {
    font-size: 4rem;
    animation: resultPop 0.6s var(--ease-spring);
}

@keyframes resultPop {
    0% { transform: scale(0) rotate(-30deg); opacity: 0; }
    60% { transform: scale(1.2) rotate(5deg); opacity: 1; }
    100% { transform: scale(1) rotate(0deg); opacity: 1; }
}

.result-message {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-align: center;
    padding: 0.5rem 1rem;
    background: var(--bg-sunken);
    border-radius: var(--radius);
    line-height: 1.4;
}

/* ===== Stats Screen ===== */
.stats-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    max-width: 680px;
    width: 100%;
    gap: 1.25rem;
}

@media (min-width: 1024px) {
    .stats-container {
        margin: 0 auto;
    }
}

.stats-summary {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 0.75rem;
    padding: 0 1rem;
}

/* Stats summary cards */
.stats-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 1.25rem 0.75rem;
    background: var(--bg-card);
    border: 1.5px solid var(--border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    transition: all var(--duration-fast);
    gap: 0.25rem;
}

.stats-card:nth-child(1) .stats-card-number { color: #E17055; }
.stats-card:nth-child(2) .stats-card-number { color: var(--accent); }
.stats-card:nth-child(3) .stats-card-number { color: #FDCB6E; }
.stats-card:nth-child(4) .stats-card-number { color: #00B894; }

.stats-card-number {
    font-family: var(--font-english);
    font-size: 1.75rem;
    font-weight: 800;
    color: var(--accent);
    line-height: 1;
}

.stats-card-label {
    font-size: 0.78rem;
    color: var(--text-muted);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.stats-section {
    margin-bottom: 0;
    padding: 0 1rem;
}

.stats-section-title {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.75rem;
}

/* Stats chart bars */
.stats-chart {
    display: flex;
    align-items: flex-end;
    gap: 0.35rem;
    height: 140px;
    padding: 0.75rem;
    background: var(--bg-card);
    border: 1.5px solid var(--border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
}

.chart-bar-wrap {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    height: 100%;
    justify-content: flex-end;
    gap: 0.25rem;
}

.chart-bar {
    width: 100%;
    border-radius: 4px 4px 0 0;
    background: var(--gradient-primary);
    min-height: 2px;
    transition: height 0.5s var(--ease-out);
}

.chart-bar.today {
    background: var(--gradient-warm);
    box-shadow: 0 0 8px var(--mod-tenses-glow);
}

.chart-bar-label {
    font-size: 0.68rem;
    color: var(--text-muted);
    font-weight: 600;
}

.chart-bar-value {
    font-size: 0.72rem;
    font-weight: 700;
    color: var(--text-secondary);
    font-family: var(--font-english);
}

/* Stats SRS */
.stats-srs {
    background: var(--bg-card);
    border: 1.5px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 1.25rem;
    box-shadow: var(--shadow-sm);
}

.srs-bar-container {
    height: 12px;
    background: var(--bg-sunken);
    border-radius: var(--radius-full);
    overflow: hidden;
    display: flex;
    margin-bottom: 0.75rem;
}

.srs-segment {
    height: 100%;
    transition: width 0.5s var(--ease-out);
}

.srs-legend {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.srs-legend-item {
    display: flex;
    align-items: center;
    gap: 0.3rem;
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-secondary);
}

.srs-legend-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
}

/* Stats missed words */
.stats-missed {
    background: var(--bg-card);
    border: 1.5px solid var(--border);
    border-radius: var(--radius-lg);
    overflow-y: auto;
    max-height: 400px;
    box-shadow: var(--shadow-sm);
}

.missed-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 1rem;
    border-bottom: 1px solid var(--border);
    font-size: 0.875rem;
}

.missed-item:last-child {
    border-bottom: none;
}

.missed-info {
    display: flex;
    align-items: baseline;
    gap: 0.5rem;
    flex: 1;
    min-width: 0;
}

.missed-rank {
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    font-size: 0.75rem;
    font-weight: 700;
    background: var(--bg-sunken);
    color: var(--text-muted);
    flex-shrink: 0;
}

.missed-rank.gold { background: #FFEAA7; color: #D97706; }
.missed-rank.silver { background: #E8EAF2; color: #5C6180; }
.missed-rank.bronze { background: #FDEAE5; color: #E17055; }

.missed-word {
    font-family: var(--font-english);
    font-weight: 700;
    color: var(--text-primary);
    flex: 1;
}

.missed-meaning {
    color: var(--text-muted);
    font-weight: 500;
    flex: 1;
}

.missed-count {
    padding: 0.2rem 0.6rem;
    background: var(--wrong-bg);
    color: var(--wrong);
    border-radius: var(--radius-full);
    font-size: 0.75rem;
    font-weight: 700;
    flex-shrink: 0;
    white-space: nowrap;
}

/* ===== Typing Input ===== */
.typing-input {
    width: 100%;
    padding: 0.875rem 1rem;
    background: var(--bg-sunken);
    border: 2px solid var(--border);
    border-radius: var(--radius);
    font-family: var(--font-primary);
    font-size: 1rem;
    font-weight: 500;
    color: var(--text-primary);
    transition: all var(--duration-fast);
}

.typing-input:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

.typing-input::placeholder {
    color: var(--text-muted);
    font-style: italic;
}

/* Phrases typing area */
.phrases-typing-area {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    padding: 0 1rem;
}

.phrases-hint-area {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.hint-btn {
    padding: 0.4rem 0.75rem;
    background: var(--bg-sunken);
    border: 1.5px solid var(--border);
    border-radius: var(--radius-sm);
    font-family: var(--font-primary);
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--duration-fast);
    white-space: nowrap;
}

.hint-btn:hover {
    border-color: var(--accent);
    color: var(--accent);
}

.hint-text {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--accent);
    font-family: var(--font-english);
}

/* Phrases correct answer */
.phrases-correct-answer {
    padding: 0.75rem 1rem;
    margin: 0 1rem;
    background: var(--correct-bg);
    border: 1.5px solid var(--correct-border);
    border-radius: var(--radius);
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--correct);
}

/* ===== Explanation Box ===== */
.explanation-box {
    margin: 0.5rem 1rem;
    padding: 0.75rem 1rem;
    background: var(--info-bg);
    border: 1.5px solid var(--info);
    border-radius: var(--radius);
}

.explanation-label {
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    color: var(--info);
    margin-bottom: 0.25rem;
}

.explanation-text {
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-primary);
    line-height: 1.5;
}

/* ===== Exercise Card (Tenses) ===== */
.exercise-card {
    padding: 1.25rem;
    margin: 0 1rem 0.5rem;
    background: var(--bg-card);
    border: 2px solid var(--border);
    border-radius: var(--radius-organic);
    box-shadow: var(--shadow-sm);
}

.exercise-type-badge {
    display: inline-flex;
    align-items: center;
    padding: 0.25rem 0.75rem;
    margin: 0 1rem 0.5rem;
    background: var(--mod-tenses-bg);
    color: var(--mod-tenses);
    border-radius: var(--radius-full);
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    width: fit-content;
}

/* ===== Page Indicator ===== */
.page-indicator {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-muted);
    padding: 0.25rem 0.6rem;
    background: var(--bg-sunken);
    border-radius: var(--radius-full);
    font-family: var(--font-english);
}

/* ===== Theory ===== */
.theory-viewport {
    flex: 1;
    overflow-y: auto;
    padding: 0 1rem;
    -webkit-overflow-scrolling: touch;
}

.theory-nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem 1rem;
    gap: 0.5rem;
}

.theory-dots {
    display: flex;
    gap: 0.35rem;
}

.theory-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--border);
    transition: all var(--duration-fast);
}

.theory-dot.active {
    background: var(--accent);
    width: 20px;
    border-radius: 4px;
}

/* Theory content styling */
.theory-page {
    padding: 0.5rem 0;
}

.theory-page h3 {
    font-size: 1.1rem;
    font-weight: 800;
    color: var(--text-primary);
    margin-bottom: 0.75rem;
}

.theory-page h4 {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--accent);
    margin: 1rem 0 0.5rem;
}

.theory-page p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 0.5rem;
}

.theory-page ul, .theory-page ol {
    padding-left: 1.25rem;
    margin-bottom: 0.75rem;
}

.theory-page li {
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 0.25rem;
}

.theory-page code, .theory-formula {
    font-family: var(--font-english);
    background: var(--accent-bg);
    color: var(--accent);
    padding: 0.15rem 0.4rem;
    border-radius: 4px;
    font-size: 0.85rem;
    font-weight: 500;
}

.theory-example {
    padding: 0.75rem 1rem;
    margin: 0.5rem 0;
    background: var(--bg-sunken);
    border-left: 3px solid var(--accent);
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

.theory-example .en {
    font-family: var(--font-english);
    font-weight: 700;
    font-size: 0.9rem;
    color: var(--text-primary);
}

.theory-example .vi {
    font-size: 0.85rem;
    color: var(--text-muted);
    font-style: italic;
    margin-top: 0.15rem;
}

/* ===== Phrases Specific ===== */
.phrases-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    max-width: 600px;
    width: 100%;
    margin: 0 auto;
}

.phrases-stats-bar {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    padding: 0 1rem 0.5rem;
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-muted);
}

.phrases-categories {
    flex: 1;
    overflow-y: auto;
    padding: 0 1rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.phrases-question-card {
    position: relative;
    padding: 1.25rem;
    margin: 0 1rem 0.5rem;
    background: var(--bg-card);
    border: 2px solid var(--border);
    border-radius: var(--radius-organic);
    box-shadow: var(--shadow-sm);
}

.phrases-question-text {
    font-size: 1.05rem;
    font-weight: 600;
    color: var(--text-primary);
    line-height: 1.5;
    text-align: center;
}

.phrases-speak-row {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    margin-top: 0.75rem;
}

.speed-btn {
    padding: 0.3rem 0.6rem;
    background: var(--bg-sunken);
    border: 1.5px solid var(--border);
    border-radius: var(--radius-sm);
    font-family: var(--font-primary);
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-muted);
    cursor: pointer;
    transition: all var(--duration-fast);
}

.speed-btn:hover {
    border-color: var(--accent);
    color: var(--accent);
}

.bookmark-btn {
    position: absolute;
    top: 0.75rem;
    right: 0.75rem;
    background: transparent;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    transition: all var(--duration-fast);
    padding: 0.25rem;
}

.bookmark-btn:hover, .bookmark-btn.active {
    color: #FDCB6E;
    transform: scale(1.1);
}

.bookmark-btn.active svg {
    fill: #FDCB6E;
}

.phrases-direction-badge {
    display: inline-flex;
    align-items: center;
    padding: 0.25rem 0.75rem;
    margin: 0 1rem 0.5rem;
    background: var(--mod-phrases-bg);
    color: var(--mod-phrases);
    border-radius: var(--radius-full);
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    width: fit-content;
}

/* Phrases MC area */
.phrases-mc-area {
    padding: 0;
}

/* Phrases favorites */
.phrases-fav-list {
    flex: 1;
    overflow-y: auto;
    padding: 0 1rem;
}

.fav-count {
    font-size: 0.8rem;
    font-weight: 700;
    color: var(--accent);
    padding: 0.2rem 0.6rem;
    background: var(--accent-bg);
    border-radius: var(--radius-full);
}

.fav-item {
    padding: 0.75rem;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: flex-start;
    gap: 0.5rem;
}

.fav-item:last-child {
    border-bottom: none;
}

.fav-item-text {
    flex: 1;
}

.fav-item-en {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-primary);
    line-height: 1.4;
}

.fav-item-vi {
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-top: 0.15rem;
}

.fav-remove-btn {
    background: transparent;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    font-size: 1.1rem;
    padding: 0.25rem;
    transition: color var(--duration-fast);
}

.fav-remove-btn:hover {
    color: var(--wrong);
}

/* ===== Confetti ===== */
.confetti-container {
    position: fixed;
    inset: 0;
    pointer-events: none;
    z-index: 9999;
    overflow: hidden;
}

.confetti-particle {
    position: absolute;
    width: 8px;
    height: 8px;
    opacity: 0;
}

.confetti-particle.animate {
    animation: confettiFall 1s var(--ease-out) forwards;
}

@keyframes confettiFall {
    0% {
        opacity: 1;
        transform: translate(0, 0) rotate(0deg) scale(1);
    }
    100% {
        opacity: 0;
        transform: translate(var(--tx, 0), var(--ty, -100px)) rotate(720deg) scale(0.3);
    }
}

/* ===== Irregular Verbs FAB ===== */
.iv-fab {
    position: fixed;
    bottom: 1.5rem;
    right: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.35rem;
    padding: 0.65rem 1rem;
    background: var(--gradient-primary);
    color: white;
    border: none;
    border-radius: var(--radius-full);
    font-family: var(--font-primary);
    font-size: 0.8rem;
    font-weight: 700;
    cursor: pointer;
    box-shadow: var(--shadow-lg), var(--shadow-glow);
    z-index: 100;
    transition: all var(--duration-fast) var(--ease-spring);
}

.iv-fab:hover {
    transform: translateY(-2px) scale(1.05);
    box-shadow: var(--shadow-xl), var(--shadow-glow);
}

.iv-fab:active {
    transform: scale(0.95);
}

.iv-fab-icon {
    font-size: 1rem;
}

.iv-fab-label {
    font-size: 0.75rem;
    font-weight: 700;
}

/* IV Overlay + Modal */
.iv-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: var(--bg-overlay);
    backdrop-filter: blur(8px);
    z-index: 200;
    align-items: flex-end;
    justify-content: center;
}

.iv-overlay.active {
    display: flex;
    animation: overlayFadeIn 0.2s ease;
}

@keyframes overlayFadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.iv-modal {
    background: var(--bg-card);
    border-radius: var(--radius-xl) var(--radius-xl) 0 0;
    max-height: 85vh;
    width: 100%;
    max-width: 560px;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    animation: modalSlideUp 0.3s var(--ease-spring);
}

@keyframes modalSlideUp {
    from { transform: translateY(100%); }
    to { transform: translateY(0); }
}

@media (min-width: 640px) {
    .iv-overlay {
        align-items: center;
    }
    .iv-modal {
        border-radius: var(--radius-xl);
        max-height: 75vh;
    }
}

.iv-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem 1.25rem;
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    background: var(--bg-card);
    z-index: 1;
}

.iv-title {
    font-size: 1.05rem;
    font-weight: 800;
    color: var(--text-primary);
}

.iv-close-btn {
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: none;
    background: var(--bg-sunken);
    color: var(--text-secondary);
    border-radius: 50%;
    font-size: 1.25rem;
    cursor: pointer;
    transition: all var(--duration-fast);
}

.iv-close-btn:hover {
    background: var(--wrong-bg);
    color: var(--wrong);
}

.iv-search-wrap {
    padding: 0.75rem 1.25rem;
}

.iv-search {
    width: 100%;
    padding: 0.7rem 1rem 0.7rem 2.5rem;
    background: var(--bg-sunken);
    border: 2px solid var(--border);
    border-radius: var(--radius);
    font-family: var(--font-primary);
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-primary);
    transition: all var(--duration-fast);
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' fill='%239298B8' viewBox='0 0 24 24'%3E%3Ccircle cx='11' cy='11' r='8' stroke='%239298B8' stroke-width='2' fill='none'/%3E%3Cline x1='21' y1='21' x2='16.65' y2='16.65' stroke='%239298B8' stroke-width='2'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: 0.75rem center;
}

.iv-search:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

/* IV Table */
.iv-table-header {
    display: flex;
    padding: 0.5rem 1.25rem;
    font-size: 0.72rem;
    font-weight: 700;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    border-bottom: 1px solid var(--border);
}

.iv-list {
    flex: 1;
    overflow-y: auto;
    padding: 0 1.25rem;
    -webkit-overflow-scrolling: touch;
}

.iv-row {
    display: flex;
    padding: 0.6rem 0;
    border-bottom: 1px solid rgba(0,0,0,0.04);
    font-size: 0.8rem;
    line-height: 1.4;
    align-items: baseline;
}

.iv-row:last-child {
    border-bottom: none;
}

.iv-col-v1 {
    width: 18%;
    min-width: 0;
    flex-shrink: 0;
    font-weight: 700;
    color: var(--accent);
    font-family: var(--font-english);
    font-size: 0.8rem;
    word-break: break-word;
}

.iv-col-v2 {
    width: 24%;
    min-width: 0;
    flex-shrink: 0;
    color: var(--text-primary);
    font-family: var(--font-english);
    font-size: 0.75rem;
    word-break: break-word;
}

.iv-col-v3 {
    width: 24%;
    min-width: 0;
    flex-shrink: 0;
    color: var(--text-primary);
    font-family: var(--font-english);
    font-size: 0.75rem;
    word-break: break-word;
}

.iv-col-vi {
    width: 34%;
    min-width: 0;
    flex-shrink: 1;
    color: var(--text-muted);
    font-size: 0.75rem;
    word-break: break-word;
}

.iv-count {
    padding: 0.5rem 1.25rem;
    font-size: 0.75rem;
    color: var(--text-muted);
    text-align: center;
    border-top: 1px solid var(--border);
    font-weight: 600;
}

/* ===== Bottom Tab Navigation (Mobile) ===== */
.bottom-nav {
    display: flex;
    align-items: center;
    justify-content: space-around;
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    height: 64px;
    background: var(--bg-card);
    border-top: 1px solid var(--border);
    z-index: 50;
    padding-bottom: env(safe-area-inset-bottom);
    transition: transform 0.3s var(--ease-out), background var(--transition), border-color var(--transition);
}

.bottom-nav--hidden {
    transform: translateY(100%);
}

.bottom-nav-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 2px;
    flex: 1;
    height: 100%;
    border: none;
    background: none;
    cursor: pointer;
    color: var(--text-muted);
    transition: color var(--duration-fast);
    position: relative;
    font-family: var(--font-primary);
    -webkit-tap-highlight-color: transparent;
}

.bottom-nav-icon {
    font-size: 1.3rem;
    line-height: 1;
    transition: transform var(--duration-fast) var(--ease-spring);
}

.bottom-nav-label {
    font-size: 0.72rem;
    font-weight: 600;
    letter-spacing: 0.01em;
}

.bottom-nav-item.active {
    color: var(--accent);
}

.bottom-nav-item.active .bottom-nav-icon {
    transform: scale(1.15);
}

.bottom-nav-item.active::after {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 32px;
    height: 3px;
    background: var(--accent);
    border-radius: 0 0 3px 3px;
}

/* Add padding to main-content on mobile so content isn't hidden behind bottom nav */
.main-content {
    padding-bottom: 72px;
}

/* Move IV FAB above bottom nav on mobile */
.iv-fab {
    bottom: 80px;
}

/* ===== Gamification Bar ===== */
.gamification-bar {
    display: flex;
    align-items: center;
    gap: 1rem;
    width: 100%;
    padding: 0.75rem 1rem;
    background: var(--bg-card);
    border: 1.5px solid var(--border);
    border-radius: var(--radius-lg);
    margin-bottom: 1rem;
    box-shadow: var(--shadow-sm);
    transition: background var(--transition), border-color var(--transition);
}

.xp-section {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    flex: 1;
    min-width: 0;
}

.level-badge {
    font-family: var(--font-english);
    font-size: 0.8rem;
    font-weight: 700;
    color: var(--text-inverse);
    background: var(--gradient-primary);
    padding: 0.2rem 0.6rem;
    border-radius: var(--radius-full);
    white-space: nowrap;
    flex-shrink: 0;
}

.xp-bar-wrap {
    flex: 1;
    height: 8px;
    background: var(--bg-sunken);
    border-radius: var(--radius-full);
    overflow: hidden;
    min-width: 60px;
}

.xp-bar {
    height: 100%;
    width: 0%;
    background: var(--gradient-cool);
    border-radius: var(--radius-full);
    transition: width 0.6s var(--ease-out);
}

.xp-text {
    font-size: 0.72rem;
    font-weight: 700;
    color: var(--text-muted);
    white-space: nowrap;
    flex-shrink: 0;
}

.streak-display-large {
    display: flex;
    align-items: center;
    gap: 0.3rem;
    flex-shrink: 0;
}

.streak-flame-lg {
    font-size: 1.4rem;
    animation: flamePulse 2s ease-in-out infinite;
}

@keyframes flamePulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.1); }
}

.streak-number-lg {
    font-family: var(--font-english);
    font-size: 1.1rem;
    font-weight: 800;
    color: var(--text-primary);
}

/* ===== XP Float Animation ===== */
.xp-float {
    position: fixed;
    font-family: var(--font-english);
    font-weight: 800;
    color: var(--correct);
    font-size: 1.25rem;
    pointer-events: none;
    z-index: 999;
    animation: xpFloat 1s var(--ease-out) forwards;
}

@keyframes xpFloat {
    0% { opacity: 1; transform: translateY(0) scale(1); }
    100% { opacity: 0; transform: translateY(-60px) scale(1.3); }
}

/* ===== Screen Directional Transitions ===== */
.screen.enter-right { animation: slideInRight 0.3s var(--ease-out); }
.screen.enter-left { animation: slideInLeft 0.3s var(--ease-out); }

@keyframes slideInRight {
    from { opacity: 0; transform: translateX(30px); }
    to { opacity: 1; transform: translateX(0); }
}

@keyframes slideInLeft {
    from { opacity: 0; transform: translateX(-30px); }
    to { opacity: 1; transform: translateX(0); }
}

/* ===== Desktop Responsive ===== */
@media (min-width: 1024px) {
    .screen {
        min-height: auto;
    }

    /* Hide bottom nav on desktop */
    .bottom-nav {
        display: none;
    }

    /* Reset mobile padding on desktop */
    .main-content {
        padding-bottom: 0;
    }

    /* Reset IV FAB position on desktop */
    .iv-fab {
        bottom: 1.5rem;
    }

    .start-container {
        padding: 3rem 2rem;
        max-width: 720px;
    }

    .quiz-container {
        max-width: 680px;
    }

    .module-grid {
        gap: 1.25rem;
    }

    .module-card {
        padding: 1.5rem 1rem 1.25rem;
    }

    .module-icon {
        width: 64px;
        height: 64px;
        font-size: 1.5rem;
    }

    .options-grid {
        padding: 0 2rem;
        gap: 0.75rem;
    }

    .option-btn {
        min-height: 64px;
        padding: 1rem 1rem 1rem 2.5rem;
        font-size: 0.95rem;
    }

    .word-card {
        margin: 1rem 2rem;
        padding: 2rem;
    }

    .word-text {
        font-size: 2rem;
    }

    .stats-summary {
        grid-template-columns: repeat(4, 1fr);
        gap: 1rem;
    }

    .stats-card {
        padding: 1.5rem 1rem;
    }

    .stats-card-number {
        font-size: 2rem;
    }

    .stats-chart {
        height: 160px;
    }

    /* Compact top-bar on desktop — sidebar already handles nav */
    .top-bar {
        padding: 0.5rem 1.5rem;
        position: relative;
        background: transparent;
    }

    .top-bar-title {
        font-size: 0.9rem;
        font-weight: 600;
    }

    .icon-btn {
        width: 32px;
        height: 32px;
        border-width: 1.5px;
    }

    .icon-btn svg {
        width: 18px;
        height: 18px;
    }

    /* Hide mobile dark mode toggle on desktop (sidebar has one) */
    #start-screen .start-options .toggle-option:has(#darkmode-toggle) {
        display: none;
    }
}

/* Small mobile adjustments */
@media (max-width: 380px) {
    .options-grid {
        grid-template-columns: 1fr;
    }

    .module-grid {
        grid-template-columns: 1fr;
    }

    .word-text {
        font-size: 1.4rem;
    }
}

/* ===== Scrollbar Styling ===== */
::-webkit-scrollbar {
    width: 4px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

::-webkit-scrollbar-thumb {
    background: var(--border);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
}

/* ===== Selection Color ===== */
::selection {
    background: var(--accent-bg);
    color: var(--accent);
}

/* ===== Accessibility: Focus Visible ===== */
*:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

button:focus:not(:focus-visible) {
    outline: none;
}