/* ========================================
   ENGLISH CHAMPION - Modern Educational Game
   Pixelplay – Learn English by Grade (1-10)
   ======================================== */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800;900&family=JetBrains+Mono:wght@500&display=swap');

/* ---- CSS Variables ---- */
:root {
    --bg-primary: #080c18;
    --bg-secondary: #0f1528;
    --bg-card: rgba(18, 26, 52, 0.85);
    --bg-card-hover: rgba(26, 36, 68, 0.95);
    --bg-glass: rgba(255, 255, 255, 0.04);
    --bg-glass-hover: rgba(255, 255, 255, 0.08);

    --text-primary: #eef1f8;
    --text-secondary: #96a1bf;
    --text-muted: #5e6a87;

    --accent-teal: #0ea5e9;
    --accent-emerald: #10b981;
    --accent-blue: #3b82f6;
    --accent-purple: #8b5cf6;
    --accent-pink: #ec4899;
    --accent-green: #22c55e;
    --accent-yellow: #eab308;
    --accent-red: #ef4444;
    --accent-orange: #f97316;
    --accent-cyan: #06b6d4;

    --gradient-primary: linear-gradient(135deg, #0ea5e9, #10b981);
    --gradient-success: linear-gradient(135deg, #22c55e, #06b6d4);
    --gradient-danger: linear-gradient(135deg, #ef4444, #ec4899);
    --gradient-warm: linear-gradient(135deg, #f97316, #eab308);
    --gradient-hero: linear-gradient(135deg, #0ea5e9 0%, #3b82f6 40%, #8b5cf6 100%);

    --border-subtle: rgba(255, 255, 255, 0.06);
    --border-card: rgba(255, 255, 255, 0.08);
    --border-focus: rgba(14, 165, 233, 0.5);

    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.5);
    --shadow-glow-teal: 0 0 30px rgba(14, 165, 233, 0.15);
    --shadow-glow-green: 0 0 30px rgba(16, 185, 129, 0.15);
    --shadow-glow-red: 0 0 30px rgba(239, 68, 68, 0.15);

    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --radius-full: 9999px;

    --transition-fast: 0.15s ease;
    --transition-normal: 0.25s ease;
    --transition-smooth: 0.4s cubic-bezier(0.4, 0, 0.2, 1);

    /* Grade accent colors */
    --grade-1: #f472b6;
    --grade-2: #fb923c;
    --grade-3: #fbbf24;
    --grade-4: #34d399;
    --grade-5: #22d3ee;
    --grade-6: #60a5fa;
    --grade-7: #818cf8;
    --grade-8: #a78bfa;
    --grade-9: #f0abfc;
    --grade-10: #f87171;
}

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

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    line-height: 1.6;
    overflow-x: hidden;
    background-image:
        radial-gradient(ellipse 80% 60% at 10% 10%, rgba(14, 165, 233, 0.06) 0%, transparent 60%),
        radial-gradient(ellipse 60% 50% at 90% 90%, rgba(16, 185, 129, 0.05) 0%, transparent 60%);
}

/* ---- Top Navigation ---- */
.top-nav {
    position: sticky;
    top: 0;
    z-index: 100;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 20px;
    height: 56px;
    background: rgba(8, 12, 24, 0.92);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border-subtle);
}

.nav-left {
    display: flex;
    align-items: center;
    gap: 12px;
}

.nav-back {
    display: flex;
    align-items: center;
    gap: 4px;
    background: none;
    border: none;
    color: var(--text-secondary);
    font-size: 0.9rem;
    cursor: pointer;
    padding: 6px 10px;
    border-radius: var(--radius-sm);
    transition: var(--transition-fast);
    font-family: inherit;
}
.nav-back:hover {
    background: var(--bg-glass-hover);
    color: var(--text-primary);
}
.nav-back span:first-child {
    font-size: 1.1rem;
}

.nav-logo {
    font-weight: 800;
    font-size: 1.1rem;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.02em;
}

.nav-right {
    display: flex;
    align-items: center;
    gap: 10px;
}

.nav-xp {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--accent-teal);
    display: flex;
    align-items: center;
    gap: 4px;
}
.xp-icon { font-size: 1rem; }

.nav-btn {
    background: none;
    border: none;
    font-size: 1.1rem;
    cursor: pointer;
    padding: 6px;
    border-radius: var(--radius-sm);
    transition: var(--transition-fast);
    line-height: 1;
}
.nav-btn:hover {
    background: var(--bg-glass-hover);
}

/* ---- Screen Management ---- */
.screen {
    display: none;
    max-width: 880px;
    margin: 0 auto;
    padding: 24px 16px 40px;
    animation: screenFadeIn 0.35s ease;
}
.screen.active {
    display: block;
}

@keyframes screenFadeIn {
    from { opacity: 0; transform: translateY(12px); }
    to { opacity: 1; transform: translateY(0); }
}

/* ---- Home Screen ---- */
.home-hero {
    text-align: center;
    padding: 40px 0 32px;
}
.home-hero h1 {
    font-size: 2.4rem;
    font-weight: 900;
    background: var(--gradient-hero);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.03em;
    line-height: 1.15;
    margin-bottom: 10px;
}
.home-hero p {
    color: var(--text-secondary);
    font-size: 1.05rem;
    max-width: 420px;
    margin: 0 auto;
}

.home-subtitle {
    display: inline-block;
    background: var(--gradient-primary);
    color: #fff;
    font-weight: 700;
    font-size: 0.75rem;
    padding: 4px 14px;
    border-radius: var(--radius-full);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    margin-bottom: 14px;
}

/* Grade Grid */
.grade-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(135px, 1fr));
    gap: 12px;
    margin-top: 28px;
}

.grade-card {
    position: relative;
    background: var(--bg-card);
    border: 1px solid var(--border-card);
    border-radius: var(--radius-lg);
    padding: 22px 12px 18px;
    text-align: center;
    cursor: pointer;
    transition: var(--transition-smooth);
    overflow: hidden;
}
.grade-card::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 3px;
    background: var(--grade-color, var(--accent-teal));
    opacity: 0.7;
    transition: var(--transition-normal);
}
.grade-card:hover {
    background: var(--bg-card-hover);
    transform: translateY(-3px);
    border-color: rgba(255, 255, 255, 0.12);
    box-shadow: var(--shadow-md);
}
.grade-card:hover::before {
    opacity: 1;
    height: 4px;
}

.grade-number {
    font-size: 1.6rem;
    font-weight: 800;
    color: var(--grade-color, var(--accent-teal));
    line-height: 1;
    margin-bottom: 6px;
}
.grade-label {
    font-size: 0.78rem;
    color: var(--text-secondary);
    font-weight: 500;
}
.grade-stars {
    margin-top: 8px;
    font-size: 0.7rem;
    letter-spacing: 2px;
}

/* ---- Topic Screen ---- */
.topics-header {
    text-align: center;
    padding: 32px 0 8px;
}
.topics-header h2 {
    font-size: 1.7rem;
    font-weight: 800;
    letter-spacing: -0.02em;
}
.topics-header p {
    color: var(--text-secondary);
    margin-top: 4px;
}
.topics-grade-badge {
    display: inline-block;
    font-size: 0.7rem;
    font-weight: 700;
    padding: 3px 12px;
    border-radius: var(--radius-full);
    text-transform: uppercase;
    letter-spacing: 0.06em;
    margin-bottom: 10px;
}

.topics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    gap: 14px;
    margin-top: 20px;
}

.topic-card {
    background: var(--bg-card);
    border: 1px solid var(--border-card);
    border-radius: var(--radius-lg);
    padding: 20px;
    cursor: pointer;
    transition: var(--transition-smooth);
    position: relative;
    overflow: hidden;
}
.topic-card:hover {
    background: var(--bg-card-hover);
    transform: translateY(-2px);
    border-color: rgba(255, 255, 255, 0.12);
    box-shadow: var(--shadow-md);
}
.topic-icon {
    font-size: 1.8rem;
    margin-bottom: 8px;
    display: block;
}
.topic-name {
    font-size: 1rem;
    font-weight: 700;
    margin-bottom: 4px;
}
.topic-desc {
    font-size: 0.82rem;
    color: var(--text-secondary);
    line-height: 1.45;
}
.topic-stars {
    margin-top: 10px;
    font-size: 0.8rem;
    letter-spacing: 1px;
}
.topic-badge {
    position: absolute;
    top: 12px;
    right: 12px;
    font-size: 0.65rem;
    font-weight: 700;
    padding: 2px 8px;
    border-radius: var(--radius-full);
    background: rgba(14, 165, 233, 0.15);
    color: var(--accent-teal);
}

/* Module type badges */
.module-type {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    font-size: 0.68rem;
    font-weight: 600;
    padding: 3px 10px;
    border-radius: var(--radius-full);
    margin-top: 8px;
}
.module-type.vocab {
    background: rgba(59, 130, 246, 0.12);
    color: #60a5fa;
}
.module-type.grammar {
    background: rgba(139, 92, 246, 0.12);
    color: #a78bfa;
}
.module-type.reading {
    background: rgba(16, 185, 129, 0.12);
    color: #34d399;
}
.module-type.listening {
    background: rgba(234, 179, 8, 0.12);
    color: #fbbf24;
}

/* ---- Quiz Screen ---- */
.quiz-header {
    text-align: center;
    margin-bottom: 20px;
}
.quiz-progress-bar {
    width: 100%;
    height: 6px;
    background: var(--bg-glass);
    border-radius: var(--radius-full);
    margin: 16px 0 24px;
    overflow: hidden;
}
.quiz-progress-fill {
    height: 100%;
    border-radius: var(--radius-full);
    background: var(--gradient-primary);
    transition: width 0.4s ease;
}

.quiz-counter {
    font-size: 0.8rem;
    color: var(--text-muted);
    font-weight: 500;
}

.quiz-question-box {
    background: var(--bg-card);
    border: 1px solid var(--border-card);
    border-radius: var(--radius-xl);
    padding: 32px 24px;
    margin-bottom: 20px;
    animation: questionSlideIn 0.3s ease;
}

@keyframes questionSlideIn {
    from { opacity: 0; transform: translateX(20px); }
    to { opacity: 1; transform: translateX(0); }
}

.quiz-question-text {
    font-size: 1.2rem;
    font-weight: 700;
    line-height: 1.5;
    text-align: center;
    margin-bottom: 8px;
}
.quiz-question-hint {
    font-size: 0.82rem;
    color: var(--text-muted);
    text-align: center;
    cursor: pointer;
    transition: var(--transition-fast);
}
.quiz-question-hint:hover {
    color: var(--accent-teal);
}

/* Reading passage */
.reading-passage {
    background: rgba(14, 165, 233, 0.04);
    border: 1px solid rgba(14, 165, 233, 0.12);
    border-radius: var(--radius-lg);
    padding: 20px 24px;
    margin-bottom: 20px;
    font-size: 1rem;
    line-height: 1.8;
    color: var(--text-primary);
}
.reading-passage .passage-title {
    font-weight: 700;
    font-size: 1.05rem;
    color: var(--accent-teal);
    margin-bottom: 10px;
}

/* Listen button */
.listen-btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    background: rgba(14, 165, 233, 0.1);
    border: 1px solid rgba(14, 165, 233, 0.25);
    color: var(--accent-teal);
    font-size: 0.82rem;
    font-weight: 600;
    padding: 8px 16px;
    border-radius: var(--radius-full);
    cursor: pointer;
    transition: var(--transition-fast);
    font-family: inherit;
    margin: 8px auto;
    display: flex;
    width: fit-content;
}
.listen-btn:hover {
    background: rgba(14, 165, 233, 0.18);
}

/* Answer Options */
.answers-grid {
    display: grid;
    gap: 10px;
}

.answer-btn {
    display: flex;
    align-items: center;
    gap: 12px;
    width: 100%;
    background: var(--bg-card);
    border: 1px solid var(--border-card);
    border-radius: var(--radius-md);
    padding: 14px 18px;
    color: var(--text-primary);
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition-normal);
    text-align: left;
    font-family: inherit;
    line-height: 1.4;
}
.answer-btn:hover:not(.disabled) {
    background: var(--bg-card-hover);
    border-color: rgba(255, 255, 255, 0.14);
    transform: translateX(4px);
}

.answer-letter {
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-sm);
    background: var(--bg-glass);
    font-weight: 700;
    font-size: 0.8rem;
    color: var(--text-secondary);
    flex-shrink: 0;
    transition: var(--transition-fast);
}

.answer-btn.correct {
    background: rgba(34, 197, 94, 0.12);
    border-color: rgba(34, 197, 94, 0.4);
    animation: correctPulse 0.5s ease;
}
.answer-btn.correct .answer-letter {
    background: var(--accent-green);
    color: #fff;
}

.answer-btn.wrong {
    background: rgba(239, 68, 68, 0.1);
    border-color: rgba(239, 68, 68, 0.35);
    animation: wrongShake 0.4s ease;
}
.answer-btn.wrong .answer-letter {
    background: var(--accent-red);
    color: #fff;
}

.answer-btn.disabled {
    pointer-events: none;
    opacity: 0.6;
}

/* Input answer */
.input-answer-wrap {
    display: flex;
    gap: 10px;
    margin-top: 4px;
}
.input-answer {
    flex: 1;
    padding: 14px 18px;
    background: var(--bg-card);
    border: 1px solid var(--border-card);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: 1rem;
    font-family: inherit;
    outline: none;
    transition: var(--transition-fast);
}
.input-answer:focus {
    border-color: var(--accent-teal);
    box-shadow: 0 0 0 3px rgba(14, 165, 233, 0.12);
}
.input-answer-submit {
    padding: 14px 24px;
    background: var(--gradient-primary);
    border: none;
    border-radius: var(--radius-md);
    color: #fff;
    font-weight: 700;
    font-size: 0.9rem;
    cursor: pointer;
    font-family: inherit;
    transition: var(--transition-fast);
    white-space: nowrap;
}
.input-answer-submit:hover {
    opacity: 0.9;
    transform: scale(1.02);
}

/* Explanation box */
.explanation-box {
    background: rgba(14, 165, 233, 0.06);
    border: 1px solid rgba(14, 165, 233, 0.15);
    border-radius: var(--radius-md);
    padding: 14px 18px;
    margin-top: 16px;
    font-size: 0.88rem;
    line-height: 1.55;
    color: var(--text-secondary);
    display: none;
}
.explanation-box.visible {
    display: block;
    animation: screenFadeIn 0.3s ease;
}
.explanation-box strong {
    color: var(--accent-teal);
}

/* Streak indicator */
.streak-indicator {
    text-align: center;
    font-size: 0.82rem;
    font-weight: 600;
    color: var(--accent-orange);
    margin-top: 14px;
    opacity: 0;
    transition: opacity 0.3s;
}
.streak-indicator.visible {
    opacity: 1;
}

@keyframes correctPulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.015); }
    100% { transform: scale(1); }
}

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

/* ---- Results Screen ---- */
.results-wrap {
    text-align: center;
    padding: 40px 0 20px;
}

.results-score-ring {
    position: relative;
    width: 160px;
    height: 160px;
    margin: 0 auto 24px;
}
.results-score-ring svg {
    transform: rotate(-90deg);
    width: 160px;
    height: 160px;
}
.results-score-ring .ring-bg {
    fill: none;
    stroke: var(--bg-glass);
    stroke-width: 10;
}
.results-score-ring .ring-fill {
    fill: none;
    stroke: url(#scoreGradient);
    stroke-width: 10;
    stroke-linecap: round;
    stroke-dasharray: 408;
    stroke-dashoffset: 408;
    transition: stroke-dashoffset 1.2s cubic-bezier(0.4, 0, 0.2, 1);
}
.results-score-label {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
}
.results-score-label .score-pct {
    font-size: 2.4rem;
    font-weight: 900;
    color: var(--text-primary);
    line-height: 1;
}
.results-score-label .score-sub {
    font-size: 0.78rem;
    color: var(--text-muted);
    margin-top: 4px;
}

.results-stars {
    font-size: 2rem;
    letter-spacing: 6px;
    margin-bottom: 20px;
}

.results-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
    margin: 24px 0;
}
.result-stat {
    background: var(--bg-card);
    border: 1px solid var(--border-card);
    border-radius: var(--radius-md);
    padding: 16px 10px;
}
.result-stat-value {
    font-size: 1.4rem;
    font-weight: 800;
    color: var(--accent-teal);
}
.result-stat-label {
    font-size: 0.72rem;
    color: var(--text-muted);
    margin-top: 2px;
}

.results-xp {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--accent-emerald);
    margin: 16px 0;
}

/* ---- Buttons ---- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 12px 24px;
    border: none;
    border-radius: var(--radius-md);
    font-size: 0.9rem;
    font-weight: 600;
    font-family: inherit;
    cursor: pointer;
    transition: var(--transition-normal);
    line-height: 1.4;
    text-decoration: none;
}
.btn-primary {
    background: var(--gradient-primary);
    color: #fff;
}
.btn-primary:hover {
    opacity: 0.9;
    transform: translateY(-1px);
    box-shadow: var(--shadow-glow-teal);
}
.btn-secondary {
    background: var(--bg-glass);
    color: var(--text-secondary);
    border: 1px solid var(--border-card);
}
.btn-secondary:hover {
    background: var(--bg-glass-hover);
    color: var(--text-primary);
}
.btn-block {
    width: 100%;
}
.btn-group {
    display: flex;
    gap: 10px;
    margin-top: 20px;
    flex-wrap: wrap;
}
.btn-group .btn {
    flex: 1;
    min-width: 140px;
}

/* ---- Toast Notification ---- */
.toast {
    position: fixed;
    top: 68px;
    left: 50%;
    transform: translateX(-50%) translateY(-20px);
    background: var(--bg-card);
    border: 1px solid var(--border-card);
    border-radius: var(--radius-md);
    padding: 12px 24px;
    font-size: 0.88rem;
    font-weight: 600;
    color: var(--text-primary);
    box-shadow: var(--shadow-lg);
    z-index: 200;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s, transform 0.3s;
    max-width: 90vw;
    text-align: center;
    backdrop-filter: blur(12px);
}
.toast.visible {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
    pointer-events: auto;
}
.toast.success {
    border-color: rgba(34, 197, 94, 0.4);
    background: rgba(34, 197, 94, 0.12);
}
.toast.error {
    border-color: rgba(239, 68, 68, 0.4);
    background: rgba(239, 68, 68, 0.1);
}
.toast.achievement {
    border-color: rgba(234, 179, 8, 0.4);
    background: rgba(234, 179, 8, 0.1);
}

/* ---- Level/XP Bar on Home ---- */
.home-level-bar {
    display: flex;
    align-items: center;
    gap: 12px;
    background: var(--bg-card);
    border: 1px solid var(--border-card);
    border-radius: var(--radius-lg);
    padding: 14px 18px;
    margin-top: 20px;
}
.level-badge {
    background: var(--gradient-primary);
    width: 44px;
    height: 44px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 800;
    font-size: 1.1rem;
    color: #fff;
    flex-shrink: 0;
}
.level-info {
    flex: 1;
    min-width: 0;
}
.level-info-top {
    display: flex;
    justify-content: space-between;
    font-size: 0.78rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 6px;
}
.level-xp-bar {
    width: 100%;
    height: 8px;
    background: var(--bg-glass);
    border-radius: var(--radius-full);
    overflow: hidden;
}
.level-xp-fill {
    height: 100%;
    background: var(--gradient-primary);
    border-radius: var(--radius-full);
    transition: width 0.6s ease;
}

/* ---- Section headings ---- */
.section-heading {
    font-size: 0.78rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-muted);
    margin: 28px 0 12px;
}

/* ---- Info card ---- */
.info-card {
    background: var(--bg-card);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-lg);
    padding: 24px 22px;
    margin: 32px 0 16px;
    line-height: 1.7;
}
.info-card h3 {
    font-size: 1.05rem;
    font-weight: 700;
    margin: 0 0 8px;
    color: var(--text-primary);
}
.info-card p {
    color: var(--text-secondary);
    font-size: 0.88rem;
    margin: 0 0 14px;
}
.info-tip {
    background: var(--bg-glass);
    border-radius: var(--radius-md);
    padding: 10px 14px;
    font-size: 0.82rem;
    color: var(--text-secondary);
    line-height: 1.6;
}
kbd {
    display: inline-block;
    background: var(--bg-glass);
    border: 1px solid var(--border-subtle);
    border-radius: 4px;
    padding: 1px 6px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.78rem;
    color: var(--accent-teal);
}

/* ---- Confetti ---- */
.confetti-piece {
    position: fixed;
    width: 8px;
    height: 8px;
    border-radius: 2px;
    z-index: 300;
    pointer-events: none;
    animation: confettiDrop 1.6s ease-out forwards;
}

@keyframes confettiDrop {
    0% { opacity: 1; transform: translateY(-10vh) rotate(0deg) scale(1); }
    100% { opacity: 0; transform: translateY(100vh) rotate(720deg) scale(0.5); }
}

/* ---- Achievement Unlock ---- */
.ach-unlock {
    position: fixed;
    bottom: 24px;
    right: 24px;
    background: var(--bg-card);
    border: 1px solid rgba(234, 179, 8, 0.35);
    border-radius: var(--radius-lg);
    padding: 16px 22px;
    display: flex;
    align-items: center;
    gap: 14px;
    box-shadow: var(--shadow-lg), 0 0 40px rgba(234, 179, 8, 0.1);
    z-index: 250;
    animation: achUnlock 0.5s ease, achUnlockOut 0.4s ease 3s forwards;
    backdrop-filter: blur(12px);
}
.ach-unlock-icon {
    font-size: 2rem;
}
.ach-unlock-text {
    font-size: 0.85rem;
}
.ach-unlock-text strong {
    display: block;
    color: var(--accent-yellow);
    font-size: 0.72rem;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    margin-bottom: 2px;
}

@keyframes achUnlock {
    from { opacity: 0; transform: translateX(60px); }
    to { opacity: 1; transform: translateX(0); }
}
@keyframes achUnlockOut {
    from { opacity: 1; }
    to { opacity: 0; pointer-events: none; }
}

/* ---- Writing area ---- */
.writing-area {
    width: 100%;
    min-height: 160px;
    padding: 16px 18px;
    background: var(--bg-card);
    border: 1px solid var(--border-card);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: 1rem;
    font-family: inherit;
    line-height: 1.7;
    resize: vertical;
    outline: none;
    transition: var(--transition-fast);
}
.writing-area:focus {
    border-color: var(--accent-teal);
    box-shadow: 0 0 0 3px rgba(14, 165, 233, 0.1);
}
.word-count {
    font-size: 0.78rem;
    color: var(--text-muted);
    text-align: right;
    margin-top: 8px;
}

/* ---- Speaking module ---- */
.speak-card {
    background: var(--bg-card);
    border: 1px solid var(--border-card);
    border-radius: var(--radius-xl);
    padding: 32px 24px;
    text-align: center;
}
.speak-word {
    font-size: 2.2rem;
    font-weight: 800;
    color: var(--accent-teal);
    margin: 16px 0;
}
.speak-ipa {
    font-size: 1rem;
    color: var(--text-muted);
    font-family: 'JetBrains Mono', monospace;
    margin-bottom: 12px;
}
.speak-result {
    margin-top: 16px;
    padding: 16px;
    border-radius: var(--radius-md);
    font-weight: 600;
}
.speak-result.good {
    background: rgba(34, 197, 94, 0.1);
    border: 1px solid rgba(34, 197, 94, 0.3);
    color: var(--accent-green);
}
.speak-result.fair {
    background: rgba(234, 179, 8, 0.1);
    border: 1px solid rgba(234, 179, 8, 0.3);
    color: var(--accent-yellow);
}
.speak-result.poor {
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.3);
    color: var(--accent-red);
}

.mic-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 28px;
    background: var(--gradient-primary);
    border: none;
    border-radius: var(--radius-full);
    color: #fff;
    font-size: 1rem;
    font-weight: 700;
    cursor: pointer;
    font-family: inherit;
    transition: var(--transition-normal);
}
.mic-btn:hover {
    transform: scale(1.04);
    box-shadow: var(--shadow-glow-teal);
}
.mic-btn.recording {
    background: var(--gradient-danger);
    animation: micPulse 1s infinite;
}
@keyframes micPulse {
    0%, 100% { box-shadow: 0 0 0 0 rgba(239, 68, 68, 0.4); }
    50% { box-shadow: 0 0 0 12px rgba(239, 68, 68, 0); }
}

/* ---- Vocabulary flashcard ---- */
.flash-card {
    perspective: 1000px;
    margin: 20px 0;
}
.flash-inner {
    background: var(--bg-card);
    border: 1px solid var(--border-card);
    border-radius: var(--radius-xl);
    padding: 40px 24px;
    text-align: center;
    min-height: 200px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    transition: var(--transition-smooth);
}
.flash-word {
    font-size: 2rem;
    font-weight: 800;
    color: var(--accent-teal);
    margin-bottom: 8px;
}
.flash-translation {
    font-size: 1.3rem;
    color: var(--accent-emerald);
    font-weight: 600;
    margin-top: 12px;
    display: none;
}
.flash-translation.visible {
    display: block;
    animation: screenFadeIn 0.3s ease;
}
.flash-example {
    font-size: 0.9rem;
    color: var(--text-secondary);
    font-style: italic;
    margin-top: 10px;
    display: none;
}
.flash-example.visible {
    display: block;
    animation: screenFadeIn 0.3s ease;
}
.flash-counter {
    font-size: 0.78rem;
    color: var(--text-muted);
    margin-top: 14px;
}

/* ---- Dialog box ---- */
.dialog-box {
    background: var(--bg-card);
    border: 1px solid var(--border-card);
    border-radius: var(--radius-lg);
    padding: 20px;
    margin: 16px 0;
}
.dialog-line {
    display: flex;
    gap: 12px;
    padding: 10px 0;
    border-bottom: 1px solid var(--border-subtle);
}
.dialog-line:last-child {
    border-bottom: none;
}
.dialog-speaker {
    font-weight: 700;
    color: var(--accent-teal);
    font-size: 0.85rem;
    min-width: 80px;
    flex-shrink: 0;
}
.dialog-text {
    font-size: 0.95rem;
    color: var(--text-primary);
    line-height: 1.5;
}
.dialog-play-btn {
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1rem;
    padding: 2px 6px;
    border-radius: var(--radius-sm);
    transition: var(--transition-fast);
}
.dialog-play-btn:hover {
    background: var(--bg-glass-hover);
}

/* ---- Responsive ---- */
@media (max-width: 768px) {
    .top-nav {
        padding: 0 12px;
    }
    .nav-back-label {
        display: none;
    }
    .screen {
        padding: 16px 12px 32px;
    }
    .home-hero h1 {
        font-size: 1.8rem;
    }
    .grade-grid {
        grid-template-columns: repeat(auto-fill, minmax(100px, 1fr));
        gap: 8px;
    }
    .grade-card {
        padding: 16px 8px 14px;
    }
    .grade-number {
        font-size: 1.3rem;
    }
    .topics-grid {
        grid-template-columns: 1fr;
    }
    .quiz-question-text {
        font-size: 1.05rem;
    }
    .results-stats {
        grid-template-columns: repeat(3, 1fr);
        gap: 8px;
    }
    .result-stat { padding: 12px 6px; }
    .result-stat-value { font-size: 1.15rem; }
    .btn-group {
        flex-direction: column;
    }
    .btn-group .btn {
        min-width: 100%;
    }
}

@media (max-width: 480px) {
    .home-hero h1 {
        font-size: 1.5rem;
    }
    .home-hero p {
        font-size: 0.9rem;
    }
    .grade-grid {
        grid-template-columns: repeat(auto-fill, minmax(85px, 1fr));
    }
    .quiz-question-box {
        padding: 22px 16px;
    }
    .answer-btn {
        padding: 12px 14px;
        font-size: 0.88rem;
    }
    .results-score-ring {
        width: 130px;
        height: 130px;
    }
    .results-score-ring svg {
        width: 130px;
        height: 130px;
    }
    .results-score-label .score-pct {
        font-size: 1.9rem;
    }
}