/* ============================
   CSS VARIABLES & THEMING
   ============================ */
:root {
    --primary: #6C63FF;
    --primary-light: #8B83FF;
    --primary-dark: #5A52E0;
    --secondary: #FF6584;
    --secondary-light: #FF8FA3;
    --success: #10B981;
    --success-light: #34D399;
    --warning: #F59E0B;
    --danger: #EF4444;
    --en-color: #00B4D8;
    --en-light: #48CAE4;

    --bg: #F0F2F5;
    --bg-card: #FFFFFF;
    --bg-input: #F8F9FA;
    --text: #1A1A2E;
    --text-secondary: #6B7280;
    --text-muted: #9CA3AF;
    --border: #E5E7EB;
    --shadow: rgba(0, 0, 0, 0.08);
    --shadow-lg: rgba(0, 0, 0, 0.12);

    --radius: 16px;
    --radius-sm: 10px;
    --radius-lg: 24px;
    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Dark Mode */
body.dark {
    --bg: #0F172A;
    --bg-card: #1E293B;
    --bg-input: #334155;
    --text: #F1F5F9;
    --text-secondary: #94A3B8;
    --text-muted: #64748B;
    --border: #334155;
    --shadow: rgba(0, 0, 0, 0.3);
    --shadow-lg: rgba(0, 0, 0, 0.5);
}

/* ============================
   RESET & BASE
   ============================ */
* { margin: 0; padding: 0; box-sizing: border-box; }

body {
    font-family: 'Quicksand', sans-serif;
    background-color: var(--bg);
    color: var(--text);
    min-height: 100vh;
    transition: background-color var(--transition), color var(--transition);
    overflow-x: hidden;
    padding-top: 70px;
}

/* ============================
   TOP BAR
   ============================ */
#top-bar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 60px;
    background: var(--bg-card);
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 20px;
    z-index: 1000;
    box-shadow: 0 2px 10px var(--shadow);
    transition: background var(--transition), border var(--transition);
}

.top-bar-left { display: flex; align-items: center; gap: 10px; }
.top-bar-right { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }

.logo-text {
    font-family: 'Fredoka One', cursive;
    font-size: 1.3rem;
    color: var(--primary);
    cursor: pointer;
    transition: transform 0.2s;
}
.logo-text:hover { transform: scale(1.05); }

.xp-pill, .level-pill, .streak-pill {
    background: var(--bg);
    padding: 4px 12px;
    border-radius: 50px;
    font-size: 0.8rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 4px;
    transition: background var(--transition);
}
.xp-pill { color: var(--warning); }
.level-pill { color: var(--primary); border: 2px solid var(--primary); background: transparent; }
.streak-pill { color: var(--danger); }

.icon-btn {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    border: none;
    background: var(--bg);
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s;
    font-size: 0.9rem;
}
.icon-btn:hover { background: var(--primary); color: white; transform: scale(1.1); }

body.dark .icon-btn { background: var(--bg-input); }

/* ============================
   SCREENS
   ============================ */
.screen {
    width: 100%;
    max-width: 900px;
    margin: 0 auto;
    padding: 20px;
    display: none;
    animation: fadeSlideIn 0.4s ease;
}
.active-screen { display: block; }

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

.screen-title {
    font-family: 'Fredoka One', cursive;
    color: var(--primary);
    text-align: center;
    margin-bottom: 24px;
    font-size: 1.8rem;
}

.back-btn {
    background: var(--bg);
    border: 1px solid var(--border);
    padding: 10px 20px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-weight: 700;
    margin-bottom: 15px;
    color: var(--text-secondary);
    transition: all 0.2s;
    font-family: 'Quicksand', sans-serif;
    font-size: 0.9rem;
    display: inline-flex;
    align-items: center;
    gap: 6px;
}
.back-btn:hover { background: var(--primary); color: white; border-color: var(--primary); }

/* ============================
   HERO / MAIN MENU
   ============================ */
.hero-section {
    text-align: center;
    margin-bottom: 30px;
}
.hero-title {
    font-family: 'Fredoka One', cursive;
    font-size: 2.2rem;
    color: var(--primary);
    margin-bottom: 8px;
}
.hero-sub {
    color: var(--text-secondary);
    font-size: 1.1rem;
    font-weight: 500;
}

/* ============================
   GRID & CARDS
   ============================ */
.grid {
    display: grid;
    gap: 16px;
}
.main-grid { grid-template-columns: repeat(auto-fill, minmax(140px, 1fr)); }
.grades-grid { grid-template-columns: repeat(3, 1fr); }
.mode-grid { grid-template-columns: repeat(2, 1fr); }

.card {
    background: var(--bg-card);
    padding: 28px 16px;
    border-radius: var(--radius-lg);
    text-align: center;
    box-shadow: 0 4px 15px var(--shadow);
    cursor: pointer;
    transition: all var(--transition);
    border: 2px solid transparent;
    position: relative;
    overflow: hidden;
    font-family: 'Quicksand', sans-serif;
}
.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    transition: height 0.3s;
}
.card:hover {
    transform: translateY(-6px);
    box-shadow: 0 12px 30px var(--shadow-lg);
}
.card:active { transform: translateY(-2px); }

.card-icon { font-size: 2.5rem; margin-bottom: 10px; }
.card-label { font-family: 'Fredoka One', cursive; font-size: 1.2rem; margin-bottom: 4px; }
.card-desc { font-size: 0.8rem; color: var(--text-muted); font-weight: 500; }

.card-math { border-color: var(--primary); }
.card-math::before { background: var(--primary); height: 4px; }
.card-math:hover { border-color: var(--primary); }
.card-math .card-label { color: var(--primary); }

.card-cz { border-color: var(--secondary); }
.card-cz::before { background: var(--secondary); height: 4px; }
.card-cz:hover { border-color: var(--secondary); }
.card-cz .card-label { color: var(--secondary); }

.card-en { border-color: var(--en-color); }
.card-en::before { background: var(--en-color); height: 4px; }
.card-en:hover { border-color: var(--en-color); }
.card-en .card-label { color: var(--en-color); }

.card-civics { border-color: #F59E0B; }
.card-civics::before { background: #F59E0B; height: 4px; }
.card-civics:hover { border-color: #F59E0B; }
.card-civics .card-label { color: #F59E0B; }

.card-nature { border-color: #10B981; }
.card-nature::before { background: #10B981; height: 4px; }
.card-nature:hover { border-color: #10B981; }
.card-nature .card-label { color: #10B981; }

.card-geo { border-color: #8B5CF6; }
.card-geo::before { background: #8B5CF6; height: 4px; }
.card-geo:hover { border-color: #8B5CF6; }
.card-geo .card-label { color: #8B5CF6; }

.card-hist { border-color: #EC4899; }
.card-hist::before { background: #EC4899; height: 4px; }
.card-hist:hover { border-color: #EC4899; }
.card-hist .card-label { color: #EC4899; }

.grade-card .card-icon {
    font-family: 'Fredoka One', cursive;
    font-size: 2.8rem;
}

.grade-progress-text {
    margin-top: 8px;
    font-size: 0.75rem;
    color: var(--text-muted);
    font-weight: 600;
}

.mode-info {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 16px;
    font-size: 0.95rem;
}

/* Mode cards */
.mode-card { border-color: var(--border); }
.mode-card .card-icon { font-size: 2rem; }
.mode-typing .card-icon { color: var(--primary); }
.mode-typing:hover { border-color: var(--primary); }
.mode-choice .card-icon { color: var(--success); }
.mode-choice:hover { border-color: var(--success); }
.mode-flash .card-icon { color: var(--warning); }
.mode-flash:hover { border-color: var(--warning); }
.mode-speed .card-icon { color: var(--danger); }
.mode-speed:hover { border-color: var(--danger); }

/* ============================
   TOPIC SUB-LIST
   ============================ */
.sub-list {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
    max-width: 700px;
    margin: 0 auto;
}

.sub-item {
    background: var(--bg-card);
    padding: 16px;
    border-radius: var(--radius);
    font-size: 0.95rem;
    font-weight: 700;
    border: 2px solid var(--en-color);
    color: var(--en-color);
    cursor: pointer;
    transition: all 0.2s;
    text-align: center;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}
.sub-item:hover { background: var(--en-color); color: white; transform: translateY(-2px); }

.sub-item .topic-check {
    font-size: 0.8rem;
    opacity: 0.7;
}

.section-header {
    font-family: 'Fredoka One', cursive;
    color: var(--text-secondary);
    margin: 25px 0 10px 0;
    text-align: center;
    font-size: 1.1rem;
}

/* ============================
   GAME HUD
   ============================ */
.game-hud {
    display: flex;
    justify-content: center;
    gap: 12px;
    margin-bottom: 12px;
    flex-wrap: wrap;
}
.hud-item {
    background: var(--bg-card);
    padding: 6px 14px;
    border-radius: 50px;
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    gap: 5px;
    box-shadow: 0 2px 8px var(--shadow);
    transition: background var(--transition);
}
.hud-streak { color: var(--danger); }

/* Progress bar */
.progress-bar-container {
    width: 100%;
    max-width: 600px;
    height: 8px;
    background: var(--border);
    border-radius: 50px;
    margin: 0 auto 20px auto;
    overflow: hidden;
}
.progress-bar {
    height: 100%;
    background: linear-gradient(90deg, var(--primary), var(--en-color));
    border-radius: 50px;
    width: 0%;
    transition: width 0.5s ease;
}

/* ============================
   GAME CONTAINER
   ============================ */
.game-container {
    background: var(--bg-card);
    padding: 30px;
    border-radius: var(--radius-lg);
    box-shadow: 0 8px 30px var(--shadow);
    text-align: center;
    max-width: 650px;
    margin: 0 auto;
    position: relative;
    transition: background var(--transition), box-shadow var(--transition);
}

.hint-label {
    color: var(--text-muted);
    font-style: italic;
    font-size: 0.9rem;
}

.question {
    font-size: 2rem;
    font-weight: 700;
    margin: 12px 0 20px 0;
    color: var(--text);
    word-break: break-word;
    min-height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: color var(--transition);
}

.input-area { margin-bottom: 16px; }

.input-area input, .input-group input {
    font-size: 1.3rem;
    padding: 12px 16px;
    width: 100%;
    max-width: 400px;
    text-align: center;
    border: 2px solid var(--border);
    border-radius: var(--radius);
    outline: none;
    background: var(--bg-input);
    color: var(--text);
    font-family: 'Quicksand', sans-serif;
    font-weight: 600;
    transition: all 0.2s;
}
.input-area input:focus, .input-group input:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(108, 99, 255, 0.15);
}

.input-group {
    margin-bottom: 16px;
    text-align: left;
}
.input-group label {
    display: block;
    font-weight: 700;
    margin-bottom: 6px;
    color: var(--text-secondary);
    font-size: 0.85rem;
}
.input-group input { max-width: 100%; text-align: left; }

.input-correct { border-color: var(--success) !important; background: rgba(16, 185, 129, 0.08) !important; }
.input-wrong { border-color: var(--danger) !important; background: rgba(239, 68, 68, 0.08) !important; animation: shake 0.4s; }

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    20% { transform: translateX(-8px); }
    40% { transform: translateX(8px); }
    60% { transform: translateX(-6px); }
    80% { transform: translateX(6px); }
}

/* ============================
   BUTTONS
   ============================ */
.btn-row {
    display: flex;
    justify-content: center;
    gap: 10px;
    flex-wrap: wrap;
    margin-bottom: 12px;
}

.btn-primary, .btn-check {
    padding: 12px 24px;
    background: var(--success);
    color: white;
    border: none;
    border-radius: var(--radius);
    font-size: 1rem;
    cursor: pointer;
    font-weight: 700;
    font-family: 'Quicksand', sans-serif;
    transition: all 0.2s;
    display: inline-flex;
    align-items: center;
    gap: 6px;
}
.btn-primary:hover, .btn-check:hover { transform: translateY(-2px); filter: brightness(1.1); }
.btn-primary:active, .btn-check:active { transform: translateY(0); }

.btn-primary { background: var(--primary); }

.btn-secondary {
    padding: 12px 24px;
    background: var(--bg);
    color: var(--text);
    border: 2px solid var(--border);
    border-radius: var(--radius);
    font-size: 1rem;
    cursor: pointer;
    font-weight: 700;
    font-family: 'Quicksand', sans-serif;
    transition: all 0.2s;
    display: inline-flex;
    align-items: center;
    gap: 6px;
}
.btn-secondary:hover { border-color: var(--primary); color: var(--primary); transform: translateY(-2px); }

.btn-hint {
    padding: 12px 24px;
    background: var(--warning);
    color: white;
    border: none;
    border-radius: var(--radius);
    font-size: 1rem;
    cursor: pointer;
    font-weight: 700;
    font-family: 'Quicksand', sans-serif;
    transition: all 0.2s;
    display: inline-flex;
    align-items: center;
    gap: 6px;
}
.btn-hint:hover { filter: brightness(1.1); transform: translateY(-2px); }

.btn-skip {
    padding: 12px 24px;
    background: transparent;
    color: var(--text-muted);
    border: 2px solid var(--border);
    border-radius: var(--radius);
    font-size: 1rem;
    cursor: pointer;
    font-weight: 700;
    font-family: 'Quicksand', sans-serif;
    transition: all 0.2s;
    display: inline-flex;
    align-items: center;
    gap: 6px;
}
.btn-skip:hover { border-color: var(--text-muted); color: var(--text-secondary); }

.btn-danger { border-color: var(--danger); color: var(--danger); }
.btn-danger:hover { background: var(--danger); color: white !important; border-color: var(--danger) !important; }

/* ============================
   KEYBOARD
   ============================ */
.keyboard {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 6px;
    margin-top: 20px;
    background: var(--bg);
    padding: 12px;
    border-radius: var(--radius);
    transition: background var(--transition);
}
.keyboard-row {
    display: flex;
    justify-content: center;
    gap: 5px;
}
.key {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 8px;
    font-weight: 700;
    cursor: pointer;
    box-shadow: 0 2px 0 var(--border);
    min-width: 38px;
    padding: 12px 8px;
    font-size: 1.15rem;
    color: var(--text);
    font-family: 'Quicksand', sans-serif;
    transition: all 0.1s;
    user-select: none;
    -webkit-tap-highlight-color: transparent;
}
.key:active {
    transform: translateY(2px);
    box-shadow: 0 0 0 var(--border);
    background: var(--primary);
    color: white;
}
.key-space {
    min-width: 140px !important;
    font-size: 0.85rem !important;
}
.key-del {
    min-width: 55px !important;
    background: var(--danger);
    color: white;
    border-color: var(--danger);
}
.key-del:active { background: #DC2626; }
.key-enter {
    min-width: 80px !important;
    background: var(--success);
    color: white;
    border-color: var(--success);
    font-size: 0.85rem !important;
}
.key-enter:active { background: #059669; }

/* Number keys for math */
.key-num {
    min-width: 56px;
    padding: 16px 12px;
    font-size: 1.4rem;
}

/* ============================
   MULTIPLE CHOICE
   ============================ */
.choices-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
    margin-top: 20px;
}
.choice-btn {
    background: var(--bg-card);
    border: 2px solid var(--border);
    border-radius: var(--radius);
    padding: 18px 14px;
    font-size: 1.1rem;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.2s;
    color: var(--text);
    font-family: 'Quicksand', sans-serif;
    word-break: break-word;
}
.choice-btn:hover { border-color: var(--primary); transform: translateY(-2px); color: var(--primary); }
.choice-correct {
    border-color: var(--success) !important;
    background: rgba(16, 185, 129, 0.15) !important;
    color: var(--success) !important;
    animation: popIn 0.3s ease;
}
.choice-wrong {
    border-color: var(--danger) !important;
    background: rgba(239, 68, 68, 0.15) !important;
    color: var(--danger) !important;
    animation: shake 0.4s;
}
@keyframes popIn {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
}

/* ============================
   FLASHCARDS
   ============================ */
.flashcard-wrapper {
    max-width: 450px;
    margin: 0 auto;
}
.flashcard {
    perspective: 1000px;
    cursor: pointer;
    height: 260px;
    margin-bottom: 20px;
}
.flashcard-inner {
    position: relative;
    width: 100%;
    height: 100%;
    transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
    transform-style: preserve-3d;
}
.flashcard.flipped .flashcard-inner {
    transform: rotateY(180deg);
}
.flashcard-front, .flashcard-back {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    border-radius: var(--radius-lg);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 30px;
    box-shadow: 0 8px 30px var(--shadow);
}
.flashcard-front {
    background: linear-gradient(135deg, var(--primary), var(--en-color));
    color: white;
}
.flashcard-back {
    background: var(--bg-card);
    color: var(--text);
    transform: rotateY(180deg);
    border: 3px solid var(--success);
}
.flash-hint { font-size: 0.9rem; opacity: 0.8; margin-bottom: 8px; }
.flash-word { font-family: 'Fredoka One', cursive; font-size: 2rem; }
.flash-tap { font-size: 0.8rem; opacity: 0.6; margin-top: 16px; }
.flash-label { font-size: 0.9rem; color: var(--text-muted); margin-bottom: 8px; }

.flash-buttons {
    display: flex;
    gap: 16px;
    justify-content: center;
}
.btn-flash-no, .btn-flash-yes {
    padding: 14px 30px;
    border: none;
    border-radius: var(--radius);
    font-size: 1.1rem;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.2s;
    font-family: 'Quicksand', sans-serif;
    display: inline-flex;
    align-items: center;
    gap: 6px;
}
.btn-flash-no { background: var(--danger); color: white; }
.btn-flash-yes { background: var(--success); color: white; }
.btn-flash-no:hover, .btn-flash-yes:hover { transform: translateY(-2px); filter: brightness(1.1); }

/* ============================
   SPEED ROUND
   ============================ */
.speed-hud {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 30px;
    margin-bottom: 20px;
}
.speed-timer-ring {
    position: relative;
    width: 90px;
    height: 90px;
}
.speed-timer-ring svg { width: 100%; height: 100%; transform: rotate(-90deg); }
.ring-bg { fill: none; stroke: var(--border); stroke-width: 6; }
.ring-fg {
    fill: none;
    stroke: var(--primary);
    stroke-width: 6;
    stroke-dasharray: 283;
    stroke-dashoffset: 0;
    stroke-linecap: round;
    transition: stroke-dashoffset 1s linear, stroke 0.3s;
}
#speed-time-left {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-family: 'Fredoka One', cursive;
    font-size: 1.6rem;
    color: var(--text);
}
.speed-score-big {
    display: flex;
    flex-direction: column;
    align-items: center;
}
.speed-score-big span {
    font-family: 'Fredoka One', cursive;
    font-size: 2.5rem;
    color: var(--primary);
}
.speed-score-big small {
    color: var(--text-muted);
    font-weight: 600;
}

.speed-question { font-size: 1.8rem; }

.speed-countdown-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 2000;
}
.countdown-number {
    font-family: 'Fredoka One', cursive;
    font-size: 8rem;
    color: white;
    animation: countPop 0.8s ease;
}
@keyframes countPop {
    0% { transform: scale(2); opacity: 0; }
    50% { transform: scale(1); opacity: 1; }
    100% { transform: scale(0.8); opacity: 0.5; }
}

/* ============================
   ROUND COMPLETE
   ============================ */
.complete-container {
    max-width: 600px;
    margin: 0 auto;
    text-align: center;
}
.complete-icon { font-size: 4rem; margin-bottom: 10px; animation: bounce 1s ease infinite; }
@keyframes bounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-10px); }
}
.complete-title {
    font-family: 'Fredoka One', cursive;
    font-size: 2rem;
    color: var(--primary);
    margin-bottom: 20px;
}

.complete-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
    margin-bottom: 20px;
}
.stat-card {
    background: var(--bg-card);
    padding: 16px 10px;
    border-radius: var(--radius);
    box-shadow: 0 4px 12px var(--shadow);
    transition: background var(--transition);
}
.stat-value {
    font-family: 'Fredoka One', cursive;
    font-size: 1.5rem;
    color: var(--primary);
}
.stat-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    font-weight: 600;
    margin-top: 2px;
}

.xp-gain-bar {
    width: 100%;
    height: 30px;
    background: var(--border);
    border-radius: 50px;
    margin: 16px 0;
    position: relative;
    overflow: hidden;
}
.xp-gain-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary), var(--en-color));
    border-radius: 50px;
    transition: width 1.5s ease;
    width: 0%;
}
#xp-gain-text {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-weight: 700;
    font-size: 0.8rem;
    color: var(--text);
}

.wrong-review {
    background: var(--bg);
    border-radius: var(--radius);
    padding: 16px;
    margin: 16px 0;
    text-align: left;
}
.wrong-review h3 { color: var(--danger); font-size: 1rem; margin-bottom: 10px; }
.wrong-item {
    background: var(--bg-card);
    padding: 8px 12px;
    border-radius: 8px;
    margin-bottom: 6px;
    font-size: 0.85rem;
    border-left: 3px solid var(--danger);
    display: flex;
    justify-content: space-between;
}
.wrong-item-q { font-weight: 700; }
.wrong-item-a { color: var(--success); font-weight: 600; }

.complete-buttons {
    display: flex;
    gap: 12px;
    justify-content: center;
    flex-wrap: wrap;
    margin-top: 16px;
}

/* ============================
   STATISTICS
   ============================ */
.stats-overview {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
    margin-bottom: 30px;
}
.stat-card.big { padding: 20px; }
.stat-card.big .stat-value { font-size: 1.8rem; }

.chart-section {
    background: var(--bg-card);
    border-radius: var(--radius);
    padding: 20px;
    margin-bottom: 20px;
    box-shadow: 0 4px 12px var(--shadow);
}
.chart-section h3 {
    color: var(--text-secondary);
    font-size: 1rem;
    margin-bottom: 12px;
}
.chart-wrapper { height: 250px; position: relative; }
.chart-small { height: 200px; }

.history-list { max-height: 300px; overflow-y: auto; }
.stats-history h3 { color: var(--text-secondary); margin-bottom: 12px; }
.history-item {
    background: var(--bg-card);
    padding: 12px 16px;
    border-radius: var(--radius-sm);
    margin-bottom: 8px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 8px var(--shadow);
    font-size: 0.85rem;
    transition: background var(--transition);
}
.history-item-left { display: flex; flex-direction: column; gap: 2px; }
.history-item-topic { font-weight: 700; color: var(--text); }
.history-item-date { color: var(--text-muted); font-size: 0.75rem; }
.history-item-right { display: flex; gap: 12px; align-items: center; }
.history-item-score { font-weight: 700; color: var(--primary); }
.history-item-acc { font-weight: 600; }

/* ============================
   ACHIEVEMENTS
   ============================ */
.achievements-preview {
    margin-top: 30px;
    text-align: center;
}
.achievements-preview h3 {
    color: var(--text-secondary);
    margin-bottom: 12px;
    cursor: pointer;
}
.achievements-preview h3:hover { color: var(--primary); }
.achievements-mini-grid {
    display: flex;
    gap: 10px;
    justify-content: center;
    flex-wrap: wrap;
}
.achievement-mini {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: var(--bg-card);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.4rem;
    box-shadow: 0 2px 8px var(--shadow);
    opacity: 0.3;
    transition: all 0.3s;
    cursor: pointer;
}
.achievement-mini.unlocked { opacity: 1; animation: glow 2s ease-in-out infinite alternate; }
@keyframes glow {
    from { box-shadow: 0 2px 8px var(--shadow); }
    to { box-shadow: 0 2px 20px rgba(108, 99, 255, 0.3); }
}

.achievements-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 16px;
}
.achievement-card {
    background: var(--bg-card);
    padding: 20px;
    border-radius: var(--radius);
    text-align: center;
    box-shadow: 0 4px 12px var(--shadow);
    opacity: 0.4;
    transition: all 0.3s;
    position: relative;
}
.achievement-card.unlocked { opacity: 1; border: 2px solid var(--warning); }
.achievement-card-icon { font-size: 2.5rem; margin-bottom: 8px; }
.achievement-card-name { font-weight: 700; font-size: 0.95rem; color: var(--text); }
.achievement-card-desc { font-size: 0.8rem; color: var(--text-muted); margin-top: 4px; }
.achievement-card-badge {
    position: absolute;
    top: -6px;
    right: -6px;
    background: var(--warning);
    color: white;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    font-size: 0.7rem;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Achievement popup */
.achievement-popup {
    position: fixed;
    top: 80px;
    right: 20px;
    z-index: 3000;
    animation: slideInRight 0.5s ease, slideOutRight 0.5s ease 3s forwards;
}
@keyframes slideInRight {
    from { transform: translateX(120%); opacity: 0; }
    to { transform: translateX(0); opacity: 1; }
}
@keyframes slideOutRight {
    from { transform: translateX(0); opacity: 1; }
    to { transform: translateX(120%); opacity: 0; }
}
.achievement-popup-inner {
    background: var(--bg-card);
    border: 2px solid var(--warning);
    border-radius: var(--radius);
    padding: 16px 20px;
    display: flex;
    align-items: center;
    gap: 12px;
    box-shadow: 0 8px 30px var(--shadow-lg);
}
.achievement-popup-icon { font-size: 2rem; }
.achievement-popup-text small { color: var(--warning); font-weight: 700; display: block; font-size: 0.7rem; }
.achievement-popup-text strong { color: var(--text); font-size: 0.95rem; }

/* ============================
   EDITOR
   ============================ */
.editor-container {
    max-width: 650px;
    margin: 0 auto;
}
.editor-list {
    max-height: 400px;
    overflow-y: auto;
    margin-bottom: 16px;
}
.q-row {
    background: var(--bg-card);
    padding: 12px;
    border-radius: var(--radius-sm);
    margin-bottom: 8px;
    display: flex;
    gap: 8px;
    align-items: center;
    border-left: 4px solid var(--primary);
    box-shadow: 0 2px 8px var(--shadow);
}
.q-row span { font-weight: 700; color: var(--text-muted); min-width: 24px; }
.q-row input {
    font-size: 0.9rem;
    padding: 8px;
    flex: 1;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: var(--bg-input);
    color: var(--text);
    font-family: 'Quicksand', sans-serif;
}
.editor-buttons { display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; }

/* ============================
   TOAST
   ============================ */
#toast-container {
    position: fixed;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 3000;
    display: flex;
    flex-direction: column;
    gap: 8px;
    align-items: center;
}
.toast {
    background: var(--bg-card);
    padding: 12px 24px;
    border-radius: 50px;
    font-weight: 700;
    font-size: 0.9rem;
    box-shadow: 0 8px 25px var(--shadow-lg);
    animation: toastIn 0.3s ease, toastOut 0.3s ease 2.5s forwards;
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--text);
}
@keyframes toastIn { from { transform: translateY(20px); opacity: 0; } to { transform: translateY(0); opacity: 1; } }
@keyframes toastOut { from { opacity: 1; } to { opacity: 0; transform: translateY(-10px); } }

/* ============================
   TEACHER BTN
   ============================ */
#teacher-login-btn {
    position: fixed;
    bottom: 10px;
    right: 10px;
    opacity: 0.2;
    cursor: pointer;
    border: none;
    background: none;
    font-size: 1.2rem;
    transition: opacity 0.3s;
}
#teacher-login-btn:hover { opacity: 0.8; }

/* ============================
   MESSAGE
   ============================ */
.message {
    min-height: 30px;
    margin: 10px 0;
    font-weight: 700;
    font-size: 1rem;
    transition: color 0.2s;
}
.win { color: var(--success); }
.error { color: var(--danger); }

/* ============================
   RECENT ACTIVITY
   ============================ */
.recent-section {
    margin-top: 30px;
}
.recent-section h3 {
    color: var(--text-secondary);
    margin-bottom: 12px;
    text-align: center;
}
#recent-list {
    display: flex;
    gap: 10px;
    overflow-x: auto;
    padding-bottom: 10px;
}
.recent-item {
    background: var(--bg-card);
    min-width: 160px;
    padding: 14px;
    border-radius: var(--radius);
    box-shadow: 0 2px 10px var(--shadow);
    font-size: 0.8rem;
    cursor: pointer;
    transition: all 0.2s;
    flex-shrink: 0;
}
.recent-item:hover { transform: translateY(-2px); }
.recent-item-topic { font-weight: 700; color: var(--text); margin-bottom: 4px; }
.recent-item-score { color: var(--primary); font-weight: 600; }

/* ============================
   RESPONSIVE
   ============================ */
@media (max-width: 768px) {
    .main-grid { grid-template-columns: repeat(2, 1fr); }
    .grades-grid { grid-template-columns: repeat(2, 1fr); }
    .mode-grid { grid-template-columns: 1fr; }
    .sub-list { grid-template-columns: 1fr; }
    .complete-stats { grid-template-columns: repeat(2, 1fr); }
    .stats-overview { grid-template-columns: repeat(2, 1fr); }
    .hero-title { font-size: 1.6rem; }
    .question { font-size: 1.5rem; }

    .top-bar-right {
        gap: 4px;
    }
    .xp-pill, .level-pill, .streak-pill {
        font-size: 0.7rem;
        padding: 3px 8px;
    }
    .icon-btn { width: 32px; height: 32px; font-size: 0.8rem; }

    .key {
        min-width: 30px !important;
        padding: 10px 6px !important;
        font-size: 1rem !important;
    }
    .key-space { min-width: 100px !important; }
    .key-del { min-width: 45px !important; }
    .key-enter { min-width: 60px !important; }
    .key-num { min-width: 44px !important; padding: 14px 8px !important; font-size: 1.2rem !important; }

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

    .game-container { padding: 20px 15px; }

    .speed-hud { gap: 15px; }
    .speed-timer-ring { width: 70px; height: 70px; }
    .speed-score-big span { font-size: 2rem; }
}

@media (max-width: 400px) {
    .key { min-width: 26px !important; padding: 8px 4px !important; font-size: 0.9rem !important; }
    .grades-grid { grid-template-columns: 1fr 1fr; }
    .game-hud { gap: 6px; }
    .hud-item { font-size: 0.75rem; padding: 4px 10px; }
}

/* ============================
   SCROLLBAR
   ============================ */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 50px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-muted); }

/* ============================
   SOUND OFF INDICATOR
   ============================ */
body.sound-off #sound-toggle i { color: var(--danger); }