/* ==========================================
   BÉ HỌC TIẾNG ANH v2 - MAIN STYLES
   ========================================== */

:root {
    --primary: #4FC3F7;
    --primary-dark: #0288D1;
    --secondary: #FFD54F;
    --secondary-dark: #FFA000;
    --success: #81C784;
    --success-dark: #388E3C;
    --danger: #E57373;
    --danger-dark: #D32F2F;
    --purple: #CE93D8;
    --pink: #F48FB1;
    --orange: #FFB74D;
    --bg: #F0F8FF;
    --card-bg: #FFFFFF;
    --text: #37474F;
    --text-light: #607D8B;
    --radius: 20px;
    --shadow: 0 4px 15px rgba(0,0,0,0.1);
    --shadow-hover: 0 8px 25px rgba(0,0,0,0.15);
}

* { margin: 0; padding: 0; box-sizing: border-box; }

body {
    font-family: 'Fredoka', sans-serif;
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
    overflow-x: hidden;
}

/* HEADER */
.app-header {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    padding: 12px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
    gap: 10px;
    flex-wrap: wrap;
}

.header-left { display: flex; align-items: center; gap: 8px; }
.header-left .mascot { font-size: 1.8rem; animation: bounce 2s infinite; }
.header-left h1 { color: white; font-size: 1.2rem; font-weight: 700; }

.header-center { flex: 1; max-width: 350px; }

.search-box { position: relative; }
.search-box input {
    width: 100%;
    padding: 10px 16px;
    border: none;
    border-radius: 25px;
    font-size: 1rem;
    font-family: 'Fredoka', sans-serif;
    outline: none;
    background: rgba(255,255,255,0.95);
}
.search-results {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: white;
    border-radius: 15px;
    box-shadow: var(--shadow-hover);
    max-height: 300px;
    overflow-y: auto;
    z-index: 200;
    display: none;
    margin-top: 5px;
}
.search-results.show { display: block; }
.search-result-item {
    padding: 12px 16px;
    display: flex;
    align-items: center;
    gap: 12px;
    cursor: pointer;
    transition: background 0.2s;
    border-bottom: 1px solid #f0f0f0;
}
.search-result-item:hover { background: #E3F2FD; }
.search-result-item .sr-emoji { font-size: 1.5rem; }
.search-result-item .sr-word { font-weight: 600; color: var(--primary-dark); }
.search-result-item .sr-vi { font-size: 0.85rem; color: var(--text-light); }

.header-right { display: flex; align-items: center; gap: 12px; }
.score-display {
    background: rgba(255,255,255,0.2);
    padding: 6px 14px;
    border-radius: 20px;
    color: white;
    font-weight: 600;
    font-size: 1rem;
}
.btn-achievements {
    background: var(--secondary);
    border: none;
    border-radius: 50%;
    width: 40px; height: 40px;
    font-size: 1.3rem;
    cursor: pointer;
    transition: transform 0.2s;
    box-shadow: var(--shadow);
}
.btn-achievements:hover { transform: scale(1.1); }

/* PAGES */
.page { display: none; padding: 20px; max-width: 900px; margin: 0 auto; animation: fadeIn 0.3s ease; }
.page.active { display: block; }

@keyframes fadeIn { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }

.page-header { margin-bottom: 20px; }
.page-header h2 { color: var(--primary-dark); font-size: 1.4rem; margin: 10px 0; }

.btn-back {
    background: none;
    border: 2px solid var(--primary);
    color: var(--primary-dark);
    padding: 8px 16px;
    border-radius: 25px;
    font-family: 'Fredoka', sans-serif;
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
}
.btn-back:hover { background: var(--primary); color: white; }

/* WELCOME */
.welcome-section { text-align: center; padding: 25px 20px; }
.welcome-mascot { font-size: 3.5rem; animation: bounce 2s infinite; }
.welcome-section h2 { font-size: 1.6rem; color: var(--primary-dark); margin: 8px 0; }
.welcome-section p { font-size: 1.1rem; color: var(--text-light); }

/* MODE SELECTOR */
.mode-selector {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
    padding: 0 10px;
    margin-bottom: 25px;
}
.mode-btn {
    background: var(--card-bg);
    border: 3px solid transparent;
    border-radius: var(--radius);
    padding: 18px 12px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    transition: all 0.3s;
    box-shadow: var(--shadow);
    font-family: 'Fredoka', sans-serif;
}
.mode-btn:hover { transform: translateY(-4px); box-shadow: var(--shadow-hover); border-color: var(--primary); }
.mode-btn:nth-child(1) { border-bottom: 4px solid var(--primary); }
.mode-btn:nth-child(2) { border-bottom: 4px solid var(--purple); }
.mode-btn:nth-child(3) { border-bottom: 4px solid var(--success); }
.mode-btn:nth-child(4) { border-bottom: 4px solid var(--pink); }
.mode-btn:nth-child(5) { border-bottom: 4px solid var(--orange); }
.mode-btn:nth-child(6) { border-bottom: 4px solid var(--secondary); }
.mode-icon { font-size: 2.2rem; }
.mode-label { font-size: 0.9rem; font-weight: 600; color: var(--text); text-align: center; }

/* TOPICS */
.topics-preview h3 { font-size: 1.2rem; color: var(--text); margin-bottom: 12px; padding: 0 10px; }
.topic-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(130px, 1fr));
    gap: 12px;
    padding: 0 10px;
}
.topic-card {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 18px 12px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s;
    box-shadow: var(--shadow);
    position: relative;
}
.topic-card:hover { transform: translateY(-4px) scale(1.02); box-shadow: var(--shadow-hover); }
.topic-card .topic-emoji { font-size: 2.2rem; display: block; margin-bottom: 6px; }
.topic-card .topic-name { font-size: 0.9rem; font-weight: 600; color: var(--text); }
.topic-card .topic-count { font-size: 0.75rem; color: var(--text-light); margin-top: 4px; }

/* PROGRESS BAR */
.progress-bar { height: 8px; background: #E0E0E0; border-radius: 10px; overflow: hidden; margin-top: 8px; }
.progress-fill { height: 100%; background: linear-gradient(90deg, var(--success), var(--primary)); border-radius: 10px; transition: width 0.5s ease; width: 0%; }

/* CARDS */
.flashcard-container { display: flex; flex-direction: column; align-items: center; gap: 18px; }
.flashcard {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 25px;
    text-align: center;
    box-shadow: var(--shadow);
    width: 100%;
    max-width: 420px;
    transition: transform 0.3s;
}
.flashcard:hover { transform: scale(1.01); }
.flashcard .card-image { font-size: 4.5rem; margin-bottom: 12px; }
.flashcard .card-word { font-size: 2rem; font-weight: 700; color: var(--primary-dark); margin-bottom: 6px; }
.flashcard .card-phonetic { font-size: 1rem; color: var(--text-light); margin-bottom: 5px; }
.flashcard .card-vi { font-size: 1rem; color: var(--text-light); margin-bottom: 5px; }
.flashcard .card-sentence { font-size: 0.95rem; color: var(--text); font-style: italic; margin: 10px 0; padding: 10px; background: #F5F5F5; border-radius: 12px; }

.btn-listen {
    background: var(--primary);
    color: white;
    border: none;
    padding: 12px 22px;
    border-radius: 25px;
    font-size: 1.05rem;
    font-family: 'Fredoka', sans-serif;
    cursor: pointer;
    transition: all 0.2s;
    box-shadow: var(--shadow);
}
.btn-listen:hover { background: var(--primary-dark); transform: scale(1.05); }

/* OPTIONS */
.vocab-options, .quiz-options {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
    width: 100%;
    max-width: 420px;
}
.vocab-option, .quiz-option {
    background: var(--card-bg);
    border: 3px solid #E0E0E0;
    border-radius: 15px;
    padding: 14px;
    font-size: 1.1rem;
    font-family: 'Fredoka', sans-serif;
    cursor: pointer;
    transition: all 0.2s;
    text-align: center;
}
.vocab-option:hover, .quiz-option:hover { border-color: var(--primary); transform: scale(1.03); }
.vocab-option.correct, .quiz-option.correct { border-color: var(--success); background: #E8F5E9; }
.vocab-option.wrong, .quiz-option.wrong { border-color: var(--danger); background: #FFEBEE; animation: shake 0.5s; }

/* NAVIGATION BUTTONS */
.flashcard-nav { display: flex; gap: 12px; margin-top: 10px; align-items: center; }
.btn-nav {
    background: var(--secondary);
    color: var(--text);
    border: none;
    padding: 11px 22px;
    border-radius: 25px;
    font-size: 0.95rem;
    font-weight: 600;
    font-family: 'Fredoka', sans-serif;
    cursor: pointer;
    transition: all 0.2s;
    box-shadow: var(--shadow);
}
.btn-nav:hover { transform: scale(1.05); background: var(--secondary-dark); color: white; }
.btn-nav:disabled { opacity: 0.5; cursor: not-allowed; transform: none; }

/* PRONUNCIATION */
.pronun-card, .writing-card, .reading-card, .quiz-card {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 25px;
    text-align: center;
    box-shadow: var(--shadow);
    max-width: 480px;
    margin: 0 auto;
}
.word-display { font-size: 2.2rem; font-weight: 700; color: var(--primary-dark); margin: 12px 0; }
.word-image { font-size: 3.5rem; margin-bottom: 8px; }

.pronun-buttons { display: flex; flex-wrap: wrap; justify-content: center; gap: 10px; margin-top: 18px; }
.btn-speak {
    background: var(--primary);
    color: white;
    border: none;
    padding: 13px 22px;
    border-radius: 25px;
    font-size: 1.05rem;
    font-family: 'Fredoka', sans-serif;
    cursor: pointer;
    transition: all 0.2s;
    box-shadow: var(--shadow);
    display: flex;
    align-items: center;
    gap: 6px;
}
.btn-speak:hover { transform: scale(1.05); }
.btn-record {
    background: var(--danger);
    color: white;
    border: none;
    padding: 13px 22px;
    border-radius: 25px;
    font-size: 1.05rem;
    font-family: 'Fredoka', sans-serif;
    cursor: pointer;
    transition: all 0.2s;
    box-shadow: var(--shadow);
    display: flex;
    align-items: center;
    gap: 6px;
}
.btn-record:hover { transform: scale(1.05); }
.btn-record.recording { animation: pulse 1s infinite; background: var(--danger-dark); }

.pronun-result { margin-top: 15px; padding: 14px; border-radius: 15px; font-size: 1rem; font-weight: 500; display: none; }
.pronun-result.show { display: block; }
.pronun-result.success { background: #E8F5E9; color: var(--success-dark); border: 2px solid var(--success); }
.pronun-result.error { background: #FFF3E0; color: var(--secondary-dark); border: 2px solid var(--orange); }

/* WRITING */
.writing-input {
    width: 100%;
    max-width: 360px;
    padding: 14px 18px;
    font-size: 1.5rem;
    font-family: 'Fredoka', sans-serif;
    text-align: center;
    border: 3px solid #E0E0E0;
    border-radius: 15px;
    outline: none;
    transition: border-color 0.3s;
    letter-spacing: 3px;
}
.writing-input:focus { border-color: var(--primary); }
.writing-input.correct { border-color: var(--success); background: #E8F5E9; }
.writing-input.wrong { border-color: var(--danger); background: #FFEBEE; }

.sentence-input {
    width: 100%;
    max-width: 400px;
    padding: 14px 18px;
    font-size: 1.2rem;
    font-family: 'Fredoka', sans-serif;
    text-align: center;
    border: 3px solid #E0E0E0;
    border-radius: 15px;
    outline: none;
    transition: border-color 0.3s;
}
.sentence-input:focus { border-color: var(--primary); }

.btn-check {
    background: var(--success);
    color: white;
    border: none;
    padding: 12px 28px;
    border-radius: 25px;
    font-size: 1.05rem;
    font-weight: 600;
    font-family: 'Fredoka', sans-serif;
    cursor: pointer;
    transition: all 0.2s;
    box-shadow: var(--shadow);
    margin-top: 12px;
}
.btn-check:hover { background: var(--success-dark); transform: scale(1.05); }

.btn-hint {
    background: var(--orange);
    color: white;
    border: none;
    padding: 10px 18px;
    border-radius: 25px;
    font-size: 0.95rem;
    font-family: 'Fredoka', sans-serif;
    cursor: pointer;
    transition: all 0.2s;
    margin-top: 8px;
}
.btn-hint:hover { background: var(--secondary-dark); transform: scale(1.05); }

.letter-boxes { display: flex; justify-content: center; gap: 6px; margin: 12px 0; flex-wrap: wrap; }
.letter-box {
    width: 40px; height: 45px;
    border: 3px solid #E0E0E0;
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--primary-dark);
    background: white;
    transition: all 0.3s;
}
.letter-box.filled { border-color: var(--primary); background: #E3F2FD; }
.letter-box.correct { border-color: var(--success); background: #E8F5E9; }
.letter-box.wrong { border-color: var(--danger); background: #FFEBEE; }

/* READING MODULE */
.reading-sentence {
    font-size: 1.4rem;
    color: var(--primary-dark);
    font-weight: 600;
    padding: 15px;
    background: #F5F5F5;
    border-radius: 15px;
    margin: 15px 0;
    line-height: 1.6;
}

.conversation-box {
    background: #F5F5F5;
    border-radius: 15px;
    padding: 15px;
    margin: 12px 0;
    text-align: left;
}
.conversation-line {
    padding: 8px 0;
    font-size: 1.1rem;
}
.conversation-line .speaker {
    font-weight: 700;
    color: var(--primary-dark);
}

/* SEARCH PAGE */
.search-page-box {
    margin-bottom: 20px;
}
.search-page-box input {
    width: 100%;
    padding: 15px 20px;
    font-size: 1.2rem;
    font-family: 'Fredoka', sans-serif;
    border: 3px solid var(--primary);
    border-radius: 25px;
    outline: none;
    transition: border-color 0.3s;
}
.search-page-box input:focus { border-color: var(--primary-dark); }

.search-word-card {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 20px;
    margin-bottom: 12px;
    box-shadow: var(--shadow);
    display: flex;
    align-items: center;
    gap: 15px;
    cursor: pointer;
    transition: all 0.2s;
}
.search-word-card:hover { transform: translateX(5px); box-shadow: var(--shadow-hover); }
.search-word-card .swc-emoji { font-size: 2.5rem; }
.search-word-card .swc-info { flex: 1; }
.search-word-card .swc-word { font-size: 1.3rem; font-weight: 700; color: var(--primary-dark); }
.search-word-card .swc-phonetic { font-size: 0.9rem; color: var(--text-light); }
.search-word-card .swc-vi { font-size: 1rem; color: var(--text); }
.search-word-card .swc-sentence { font-size: 0.85rem; color: var(--text-light); font-style: italic; margin-top: 4px; }
.search-word-card .swc-btn { background: var(--primary); color: white; border: none; border-radius: 50%; width: 36px; height: 36px; font-size: 1.2rem; cursor: pointer; }

/* ACHIEVEMENTS */
.achievements-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
    gap: 12px;
}
.achievement-card {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 18px;
    text-align: center;
    box-shadow: var(--shadow);
}
.achievement-card.locked { opacity: 0.5; filter: grayscale(0.8); }
.achievement-card .badge-icon { font-size: 2.2rem; margin-bottom: 8px; }
.achievement-card .badge-name { font-size: 0.85rem; font-weight: 600; }
.achievement-card .badge-desc { font-size: 0.75rem; color: var(--text-light); margin-top: 4px; }

.stats-section {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 22px;
    margin-bottom: 18px;
    box-shadow: var(--shadow);
}
.stats-section h3 { color: var(--primary-dark); margin-bottom: 12px; }
.stats-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 12px; }
.stat-item { text-align: center; padding: 12px; background: var(--bg); border-radius: 15px; }
.stat-item .stat-value { font-size: 1.8rem; font-weight: 700; color: var(--primary-dark); }
.stat-item .stat-label { font-size: 0.8rem; color: var(--text-light); margin-top: 4px; }

/* FEEDBACK */
.feedback-overlay {
    position: fixed;
    top: 0; left: 0; width: 100%; height: 100%;
    background: rgba(0,0,0,0.3);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
}
.feedback-overlay.hidden { display: none; }
.feedback-content {
    background: white;
    border-radius: 30px;
    padding: 35px;
    text-align: center;
    box-shadow: 0 10px 40px rgba(0,0,0,0.2);
    animation: popIn 0.3s ease;
}
.feedback-icon { font-size: 3.5rem; margin-bottom: 12px; }
.feedback-text { font-size: 1.4rem; font-weight: 600; color: var(--text); }

/* ANIMATIONS */
@keyframes bounce { 0%, 100% { transform: translateY(0); } 50% { transform: translateY(-8px); } }
@keyframes pulse { 0%, 100% { transform: scale(1); } 50% { transform: scale(1.05); } }
@keyframes shake { 0%, 100% { transform: translateX(0); } 25% { transform: translateX(-5px); } 75% { transform: translateX(5px); } }
@keyframes popIn { from { transform: scale(0.5); opacity: 0; } to { transform: scale(1); opacity: 1; } }

/* RESPONSIVE */
@media (max-width: 600px) {
    .mode-selector { grid-template-columns: repeat(2, 1fr); gap: 10px; }
    .topic-grid { grid-template-columns: repeat(2, 1fr); }
    .header-left h1 { font-size: 0.9rem; }
    .header-center { max-width: 180px; }
    .search-box input { font-size: 0.85rem; padding: 8px 12px; }
    .flashcard .card-image { font-size: 3.5rem; }
    .flashcard .card-word { font-size: 1.5rem; }
    .vocab-options, .quiz-options { grid-template-columns: 1fr 1fr; }
    .letter-box { width: 32px; height: 38px; font-size: 1.1rem; }
    .app-header { padding: 10px 12px; }
}

@media (min-width: 768px) {
    .mode-selector { grid-template-columns: repeat(3, 1fr); }
    .topic-grid { grid-template-columns: repeat(4, 1fr); }
}

@media (min-width: 1024px) {
    .mode-selector { grid-template-columns: repeat(6, 1fr); }
}