/* ========== CSS Variables ========== */
:root {
    --bg-primary: #0a0a1a;
    --bg-secondary: #12122a;
    --bg-card: rgba(255, 255, 255, 0.05);
    --bg-card-hover: rgba(255, 255, 255, 0.1);
    --text-primary: #ffffff;
    --text-secondary: rgba(255, 255, 255, 0.7);
    --text-muted: rgba(255, 255, 255, 0.5);
    --accent-primary: #7c3aed;
    --accent-secondary: #06b6d4;
    --accent-gradient: linear-gradient(135deg, #7c3aed 0%, #06b6d4 100%);
    --success: #22c55e;
    --error: #ef4444;
    --warning: #f59e0b;
    --border-radius: 16px;
    --border-radius-sm: 8px;
    --shadow-glow: 0 0 40px rgba(124, 58, 237, 0.3);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html,
body {
    height: 100%;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    overflow: hidden;
    background-position: center center;
    background-size: cover;
}

body {
    height: 100vh;
}

p,
h1,
img,
h2,
h3,
h4,
h5,
h6 {
    user-select: none;
}

/* ========== Screen System ========== */
.screen {
    display: none;
    height: 100vh;
    padding: 1rem;
    animation: fadeIn 0.5s ease-out;
}

.screen.active {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: scale(0.9);
    }

    to {
        opacity: 1;
        transform: scale(1);
    }
}

@keyframes countDown {
    0% {
        transform: scale(1.5);
        opacity: 0;
    }

    50% {
        transform: scale(1);
        opacity: 1;
    }

    100% {
        transform: scale(0.8);
        opacity: 0;
    }
}

/* ========== Menu Screen ========== */
#menu-screen {
    gap: 0.75rem;
    text-align: center;
}

.logo-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.4rem;
}

.logo-icon {
    width: 50px;
    height: 50px;
    background: var(--accent-gradient);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    box-shadow: var(--shadow-glow);
    animation: pulse 2s infinite;
}

@keyframes pulse {

    0%,
    100% {
        transform: scale(1);
    }

    50% {
        transform: scale(1.05);
    }
}

.title {
    font-size: clamp(1.5rem, 4vw, 2.2rem);
    font-weight: 800;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -1px;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 0.85rem;
    font-weight: 400;
}

/* ========== Card Container ========== */
.menu-card {
    background: var(--bg-card);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--border-radius);
    padding: 1.25rem;
    width: 100%;
    max-width: 480px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
}

.section-title {
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1.5px;
    color: var(--text-muted);
    margin-bottom: 0.5rem;
}

/* ========== Difficulty Selector ========== */
.difficulty-selector {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.difficulty-btn {
    padding: 0.6rem 0.2rem;
    border: 2px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--border-radius-sm);
    background: transparent;
    color: var(--text-secondary);
    font-family: inherit;
    font-size: 0.8rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.25rem;
}

.difficulty-btn:hover {
    border-color: rgba(255, 255, 255, 0.3);
    background: var(--bg-card-hover);
}

.difficulty-btn.selected {
    border-color: var(--accent-primary);
    background: rgba(124, 58, 237, 0.2);
    color: var(--text-primary);
}

.difficulty-btn[data-difficulty="extreme"].selected {
    border-color: #ef4444;
    background: rgba(239, 68, 68, 0.2);
}

.difficulty-btn .icon {
    font-size: 1.2rem;
}

.difficulty-btn .time {
    font-size: 0.6rem;
    color: var(--text-muted);
    font-weight: 400;
    text-align: center;
}

.difficulty-btn.selected .time {
    color: var(--accent-secondary);
}

.difficulty-btn[data-difficulty="extreme"].selected .time {
    color: #ef4444;
}

/* ========== Mode Selector ========== */
.mode-selector {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.mode-btn {
    padding: 0.7rem 0.75rem;
    border: 2px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--border-radius-sm);
    background: transparent;
    color: var(--text-secondary);
    font-family: inherit;
    font-size: 0.8rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.25rem;
}

.mode-btn:hover {
    border-color: rgba(255, 255, 255, 0.3);
    background: var(--bg-card-hover);
}

.mode-btn.selected {
    border-color: var(--accent-secondary);
    background: rgba(6, 182, 212, 0.2);
    color: var(--text-primary);
}

.mode-btn .icon {
    font-size: 1.3rem;
}

.mode-btn .description {
    font-size: 0.65rem;
    color: var(--text-muted);
    font-weight: 400;
}

.mode-btn.selected .description {
    color: var(--accent-secondary);
}

/* ========== Chapter Selector ========== */
.chapter-selector {
    margin-top: 0.75rem;
    margin-bottom: 1rem;
}

.chapter-selector-toggle {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.6rem 0.75rem;
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--border-radius-sm);
    cursor: pointer;
    transition: var(--transition);
}

.chapter-selector-toggle:hover {
    background: rgba(255, 255, 255, 0.06);
}

.chapter-selector-toggle .toggle-text {
    font-size: 0.85rem;
    font-weight: 600;
}

.chapter-selector-toggle .toggle-icon {
    transition: var(--transition);
}

.chapter-selector-toggle.open .toggle-icon {
    transform: rotate(180deg);
}

.chapter-selector-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
}

.chapter-selector-content.open {
    max-height: 350px;
    overflow-y: auto;
}

.chapter-actions {
    display: flex;
    gap: 0.5rem;
    padding: 0.5rem 0;
}

.chapter-action-btn {
    flex: 1;
    padding: 0.4rem;
    border: 1px solid rgba(255, 255, 255, 0.15);
    border-radius: var(--border-radius-sm);
    background: transparent;
    color: var(--text-secondary);
    font-family: inherit;
    font-size: 0.7rem;
    cursor: pointer;
    transition: var(--transition);
}

.chapter-action-btn:hover {
    background: rgba(124, 58, 237, 0.2);
    border-color: var(--accent-primary);
}

.chapter-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 0.4rem;
    padding: 0.5rem 0;
}

.chapter-checkbox {
    display: flex;
    align-items: center;
    gap: 0.35rem;
    padding: 0.35rem 0.5rem;
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--border-radius-sm);
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.65rem;
}

.chapter-checkbox:hover {
    background: rgba(255, 255, 255, 0.08);
}

.chapter-checkbox.selected {
    border-color: var(--accent-primary);
    background: rgba(124, 58, 237, 0.15);
}

.chapter-checkbox .check-icon {
    width: 12px;
    height: 12px;
    border: 1px solid rgba(255, 255, 255, 0.3);
    border-radius: 2px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.5rem;
    flex-shrink: 0;
}

.chapter-checkbox.selected .check-icon {
    background: var(--accent-primary);
    border-color: var(--accent-primary);
}

.chapter-checkbox .ch-name {
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

/* ========== Start Button ========== */
.start-btn,
.next-btn,
.submit-btn {
    width: 100%;
    padding: 0.85rem 1.5rem;
    border: none;
    border-radius: var(--border-radius-sm);
    background: var(--accent-gradient);
    color: white;
    font-family: inherit;
    font-size: 0.95rem;
    font-weight: 700;
    cursor: pointer;
    transition: var(--transition);
    text-transform: uppercase;
    letter-spacing: 1px;
    position: relative;
    overflow: hidden;
}

.start-btn::before,
.next-btn::before,
.submit-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: 0.5s;
}

.start-btn:hover::before,
.next-btn:hover::before,
.submit-btn:hover::before {
    left: 100%;
}

.start-btn:hover,
.next-btn:hover,
.submit-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(124, 58, 237, 0.4);
}

.start-btn:active,
.next-btn:active,
.submit-btn:active {
    transform: translateY(0);
}

/* ========== Info Cards ========== */
.info-row {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
}

.info-card {
    display: flex;
    align-items: center;
    gap: 0.3rem;
    color: var(--text-muted);
    font-size: 0.75rem;
}

.info-card .icon {
    font-size: 1rem;
}

/* ========== Exercise Screen ========== */
#exercise-screen {
    gap: 0.5rem;
    justify-content: flex-start;
    padding-top: 1rem;
}

.exercise-header {
    width: 100%;
    max-width: 600px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.5rem;
}

.progress-info {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.chapter-badge {
    background: var(--accent-gradient);
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
}

.exercise-count {
    font-size: 0.7rem;
    color: var(--text-muted);
}

.timer-display {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    background: var(--bg-card);
    padding: 0.5rem 1rem;
    border-radius: var(--border-radius-sm);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.lives-display {
    font-size: 1.2rem;
    letter-spacing: 2px;
    animation: pulse 1s infinite;
}

.timer-display.warning {
    border-color: var(--warning);
    color: var(--warning);
}

.timer-display.danger {
    border-color: var(--error);
    color: var(--error);
    animation: pulse 0.5s infinite;
}

.timer-icon {
    font-size: 1.2rem;
}

.timer-text {
    font-size: 1.1rem;
    font-weight: 700;
    font-variant-numeric: tabular-nums;
}

/* Progress Bar */
.progress-bar-container {
    width: 100%;
    max-width: 600px;
    height: 6px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 3px;
    overflow: hidden;
    margin-bottom: 1rem;
}

.progress-bar {
    height: 100%;
    background: var(--accent-gradient);
    transition: width 0.3s ease;
}

/* Question Card */
.question-card {
    background: var(--bg-card);
    backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    width: 100%;
    max-width: 600px;
    text-align: center;
    animation: slideIn 0.3s ease-out;
}

.question-number {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 0.5rem;
}

.question-text {
    position: relative;
    font-size: 1.8rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    min-height: 80px;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    border-radius: var(--border-radius-sm);
}

/* Canvas Noise Display */
#noise-canvas {
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
    image-rendering: pixelated;
    user-select: none;
    -webkit-user-select: none;
    pointer-events: none;
}

/* Write Mode Input */
.answer-input-container {
    margin-bottom: 1rem;
}

.answer-input {
    width: 100%;
    max-width: 200px;
    padding: 0.75rem 1rem;
    font-size: 1.2rem;
    font-family: inherit;
    font-weight: 600;
    text-align: center;
    background: rgba(255, 255, 255, 0.05);
    border: 2px solid rgba(255, 255, 255, 0.2);
    border-radius: var(--border-radius-sm);
    color: var(--text-primary);
    transition: var(--transition);
}

.answer-input:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 20px rgba(124, 58, 237, 0.3);
}

/* Hidden utility class */
.hidden {
    display: none !important;
}

/* Symbol Buttons for Write Mode */
.symbol-buttons {
    display: flex;
    justify-content: center;
    gap: 0.5rem;
    margin-top: 0.75rem;
    flex-wrap: wrap;
}

.symbol-btn {
    padding: 0.5rem 0.75rem;
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: var(--border-radius-sm);
    background: rgba(255, 255, 255, 0.05);
    color: var(--text-primary);
    font-family: inherit;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    min-width: 40px;
}

.symbol-btn:hover {
    background: rgba(124, 58, 237, 0.2);
    border-color: var(--accent-primary);
    transform: translateY(-2px);
}

/* Pause Overlay */
.pause-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(10, 10, 26, 0.95);
    backdrop-filter: blur(10px);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
}

.pause-overlay.active {
    opacity: 1;
    visibility: visible;
}

.pause-icon {
    font-size: 5rem;
    margin-bottom: 1rem;
    animation: pulse 2s infinite;
}

@keyframes pulse {

    0%,
    100% {
        transform: scale(1);
        opacity: 1;
    }

    50% {
        transform: scale(1.1);
        opacity: 0.8;
    }
}

.pause-text {
    font-size: 2.5rem;
    font-weight: 700;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.pause-hint {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-top: 1rem;
}

/* Choice Mode Buttons */
.choices-container {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 0.75rem;
    margin-bottom: 1rem;
}

.choice-btn {
    position: relative;
    padding: 1rem 1rem 1rem 2rem;
    border: 2px solid rgba(255, 255, 255, 0.15);
    border-radius: var(--border-radius-sm);
    background: rgba(255, 255, 255, 0.03);
    color: var(--text-primary);
    font-family: inherit;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
}

.choice-number {
    position: absolute;
    left: 0.5rem;
    top: 50%;
    transform: translateY(-50%);
    width: 1.4rem;
    height: 1.4rem;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(124, 58, 237, 0.3);
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 700;
    color: var(--accent-secondary);
}

.choice-btn:hover {
    border-color: var(--accent-primary);
    background: rgba(124, 58, 237, 0.15);
    transform: translateY(-2px);
}

.choice-btn.selected {
    border-color: var(--accent-secondary);
    background: rgba(6, 182, 212, 0.2);
}

.choice-btn.correct {
    border-color: var(--success);
    background: rgba(34, 197, 94, 0.2);
}

.choice-btn.incorrect {
    border-color: var(--error);
    background: rgba(239, 68, 68, 0.2);
}

/* Chapter Intro Overlay */
.chapter-intro {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(10, 10, 26, 0.95);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 100;
    animation: fadeIn 0.3s ease-out;
}

.chapter-intro.hidden {
    display: none;
}

.chapter-number {
    font-size: 1rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 3px;
    margin-bottom: 0.5rem;
}

.chapter-name {
    font-size: 2.5rem;
    font-weight: 800;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 0.5rem;
}

.chapter-icon {
    font-size: 4rem;
    margin-bottom: 1rem;
}

.chapter-countdown {
    font-size: 3rem;
    font-weight: 800;
    color: var(--accent-secondary);
    animation: countDown 1s ease-out infinite;
}

/* ========== Chapter Results Screen ========== */
#chapter-results-screen {
    gap: 1rem;
}

.results-card {
    background: var(--bg-card);
    backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    width: 100%;
    max-width: 500px;
    max-height: 60vh;
    overflow-y: auto;
}

.results-header {
    text-align: center;
    margin-bottom: 1rem;
}

.results-title {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.results-score {
    font-size: 2rem;
    font-weight: 800;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.results-list {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.result-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem;
    background: rgba(255, 255, 255, 0.03);
    border-radius: var(--border-radius-sm);
    border-left: 3px solid;
}

.result-item.correct {
    border-color: var(--success);
}

.result-item.incorrect {
    border-color: var(--error);
}

.result-question {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.result-answer {
    font-size: 0.85rem;
}

.result-answer.correct {
    color: var(--success);
}

.result-answer.incorrect {
    color: var(--error);
}

.accumulated-score {
    text-align: center;
    padding: 1rem;
    background: rgba(124, 58, 237, 0.1);
    border-radius: var(--border-radius-sm);
    margin-top: 1rem;
}

.accumulated-label {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.accumulated-value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--accent-secondary);
}

/* Chapter Results Enhancements */
.chapter-complete-icon {
    font-size: 3rem;
    margin-bottom: 0.5rem;
    animation: bounce 0.6s ease;
}

@keyframes bounce {

    0%,
    100% {
        transform: translateY(0);
    }

    50% {
        transform: translateY(-10px);
    }
}

.chapter-name-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: var(--bg-card);
    padding: 0.4rem 1rem;
    border-radius: 20px;
    font-size: 0.85rem;
    margin-bottom: 0.5rem;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.percentage-score {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-top: 0.25rem;
}

.chapter-stats {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin: 1rem 0;
    padding: 0.75rem;
    background: rgba(255, 255, 255, 0.03);
    border-radius: var(--border-radius-sm);
}

.stat-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.25rem;
}

.stat-value {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--accent-secondary);
}

.stat-label {
    font-size: 0.7rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.result-time {
    font-size: 0.7rem;
    color: var(--text-muted);
    margin-left: 0.5rem;
}

/* ========== Final Results Screen ========== */
#final-results-screen {
    gap: 1rem;
}

.final-score-display {
    text-align: center;
}

.final-score-label {
    font-size: 1rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 2px;
}

.final-score-value {
    font-size: 4rem;
    font-weight: 800;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.final-time {
    font-size: 1rem;
    color: var(--text-secondary);
}

/* Final Results Enhancements */
.grade-badge {
    display: inline-block;
    padding: 0.5rem 1.5rem;
    border-radius: 25px;
    font-size: 1rem;
    font-weight: 700;
    margin: 0.5rem 0;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.grade-badge.excellent {
    background: linear-gradient(135deg, #22c55e, #16a34a);
    color: white;
    box-shadow: 0 4px 15px rgba(34, 197, 94, 0.4);
}

.grade-badge.good {
    background: linear-gradient(135deg, #06b6d4, #0891b2);
    color: white;
    box-shadow: 0 4px 15px rgba(6, 182, 212, 0.4);
}

.grade-badge.average {
    background: linear-gradient(135deg, #f59e0b, #d97706);
    color: white;
    box-shadow: 0 4px 15px rgba(245, 158, 11, 0.4);
}

.grade-badge.needs-work {
    background: linear-gradient(135deg, #ef4444, #dc2626);
    color: white;
    box-shadow: 0 4px 15px rgba(239, 68, 68, 0.4);
}

.final-stats-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0.5rem;
    margin: 1rem 0;
    width: 100%;
    max-width: 500px;
}

.final-stat-card {
    background: var(--bg-card);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--border-radius-sm);
    padding: 0.75rem 0.5rem;
    text-align: center;
}

.final-stat-value {
    font-size: 1.3rem;
    font-weight: 700;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.final-stat-label {
    font-size: 0.65rem;
    color: var(--text-muted);
    text-transform: uppercase;
    margin-top: 0.25rem;
}

/* ========== Top Bar (Level & Actions) ========== */
.top-bar {
    position: absolute;
    top: 1rem;
    left: 1rem;
    right: 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    z-index: 100;
}

.level-info {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    background: rgba(0, 0, 0, 0.4);
    padding: 0.35rem 0.75rem;
    border-radius: 20px;
    border: 1px solid rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(5px);
}

.level-badge {
    background: var(--accent-gradient);
    padding: 0.2rem 0.5rem;
    border-radius: 10px;
    font-size: 0.75rem;
    font-weight: 700;
}

.xp-container {
    width: 100px;
    height: 12px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 6px;
    position: relative;
    overflow: hidden;
}

.xp-bar {
    height: 100%;
    background: linear-gradient(90deg, #f59e0b, #fbbf24);
    width: 0%;
    transition: width 0.5s ease;
}

.xp-text {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 0.55rem;
    font-weight: 600;
    color: white;
    white-space: nowrap;
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.8);
}

.top-actions {
    display: flex;
    gap: 0.5rem;
}

.icon-btn {
    background: rgba(0, 0, 0, 0.4);
    border: 1px solid rgba(255, 255, 255, 0.1);
    color: white;
    width: 36px;
    height: 36px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition);
    backdrop-filter: blur(5px);
    font-size: 1.1rem;
}

.icon-btn:hover {
    background: rgba(255, 255, 255, 0.1);
    transform: scale(1.05);
}

/* ========== Records Screen ========== */
.records-container {
    width: 100%;
    max-width: 500px;
    flex: 1;
    overflow-y: auto;
    padding: 0 1rem;
}

.record-card {
    background: var(--bg-card);
    border: 1px solid rgba(255, 255, 255, 0.05);
    border-radius: var(--border-radius-md);
    padding: 1rem;
    margin-bottom: 1rem;
}

.record-title {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    padding-bottom: 0.25rem;
}

.record-list {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.record-item {
    display: flex;
    justify-content: space-between;
    font-size: 0.8rem;
    padding: 0.4rem;
    background: rgba(255, 255, 255, 0.03);
    border-radius: var(--border-radius-sm);
}

.record-rank {
    font-weight: 700;
    color: var(--accent-secondary);
    margin-right: 0.5rem;
}

.notification {
    position: fixed;
    top: 20px;
    left: 50%;
    transform: translateX(-50%) translateY(-100px);
    background: var(--accent-gradient);
    padding: 1rem 2rem;
    border-radius: 50px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
    z-index: 1000;
    transition: transform 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    display: flex;
    align-items: center;
    gap: 1rem;
    font-weight: bold;
}

.notification.show {
    transform: translateX(-50%) translateY(0);
}

.chapter-group {
    margin-bottom: 0.75rem;
}

.chapter-group-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.5rem 0.75rem;
    background: rgba(124, 58, 237, 0.15);
    border-radius: var(--border-radius-sm);
    cursor: pointer;
    margin-bottom: 0.25rem;
    transition: var(--transition);
}

.chapter-group-header:hover {
    background: rgba(124, 58, 237, 0.25);
}

.chapter-group-title {
    font-size: 0.85rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.chapter-group-score {
    font-size: 0.8rem;
    color: var(--accent-secondary);
    font-weight: 600;
}

.chapter-group-items {
    padding-left: 0.5rem;
}

@keyframes celebrate {
    0% {
        transform: scale(1);
    }

    25% {
        transform: scale(1.1) rotate(-3deg);
    }

    50% {
        transform: scale(1.1) rotate(3deg);
    }

    75% {
        transform: scale(1.1) rotate(-3deg);
    }

    100% {
        transform: scale(1);
    }
}

.celebrate {
    animation: celebrate 0.6s ease;
}

/* ========== Floating Particles ========== */
.particles {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    overflow: hidden;
    z-index: -1;
}

.particle {
    position: absolute;
    width: 4px;
    height: 4px;
    background: var(--accent-primary);
    border-radius: 50%;
    opacity: 0.3;
    animation: float 15s infinite;
}

@keyframes float {

    0%,
    100% {
        transform: translateY(100vh) rotate(0deg);
        opacity: 0;
    }

    10% {
        opacity: 0.3;
    }

    90% {
        opacity: 0.3;
    }

    100% {
        transform: translateY(-100vh) rotate(720deg);
        opacity: 0;
    }
}

/* ========== Responsive ========== */
@media (max-width: 600px) {
    .question-text {
        font-size: 1.4rem;
    }

    .choices-container {
        grid-template-columns: 1fr 1fr;
        gap: 0.5rem;
    }

    .choice-btn {
        padding: 0.75rem;
        font-size: 0.95rem;
    }
}

/* ========== Config Screen Styles ========== */
.config-card {
    background: var(--bg-card);
    border-radius: var(--border-radius);
    padding: 1rem;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.config-title {
    font-weight: 600;
    margin-bottom: 0.75rem;
    font-size: 1rem;
}

.config-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.5rem 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

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

.config-hint {
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-top: 0.5rem;
}

.config-select {
    background: var(--bg-secondary);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: var(--border-radius-sm);
    color: var(--text-primary);
    padding: 0.4rem 0.6rem;
    font-size: 0.85rem;
    min-width: 140px;
}

.config-range {
    -webkit-appearance: none;
    appearance: none;
    width: 100px;
    height: 6px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 3px;
}

.config-range::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 14px;
    height: 14px;
    background: var(--accent-primary);
    border-radius: 50%;
    cursor: pointer;
}

.config-toggle-btn {
    background: var(--accent-gradient);
    border: none;
    color: white;
    padding: 0.5rem 1rem;
    border-radius: var(--border-radius-sm);
    cursor: pointer;
    font-size: 0.85rem;
    transition: var(--transition);
}

.config-toggle-btn:hover {
    opacity: 0.9;
    transform: scale(1.02);
}

.toggle-switch {
    position: relative;
    width: 44px;
    height: 24px;
}

.toggle-switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.toggle-slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 24px;
    transition: 0.3s;
}

.toggle-slider::before {
    content: "";
    position: absolute;
    height: 18px;
    width: 18px;
    left: 3px;
    bottom: 3px;
    background: white;
    border-radius: 50%;
    transition: 0.3s;
}

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

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

/* ========== Power-ups Styles ========== */
.powerups-bar {
    display: flex;
    gap: 0.5rem;
    justify-content: center;
    margin: 1rem 0;
    flex-wrap: wrap;
}

.powerup-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.2rem;
    background: rgba(255, 255, 255, 0.1);
    border: 2px solid rgba(255, 255, 255, 0.2);
    border-radius: var(--border-radius-sm);
    padding: 0.5rem 0.75rem;
    cursor: pointer;
    transition: var(--transition);
    position: relative;
}

.powerup-btn:hover:not(:disabled) {
    background: rgba(124, 58, 237, 0.3);
    border-color: var(--accent-primary);
    transform: scale(1.05);
}

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

.powerup-btn.active {
    background: var(--accent-gradient);
    border-color: transparent;
    animation: pulse 0.5s infinite;
}

.powerup-icon {
    font-size: 1.3rem;
}

.powerup-count {
    font-size: 0.7rem;
    background: var(--accent-secondary);
    color: white;
    padding: 0.1rem 0.35rem;
    border-radius: 10px;
    min-width: 18px;
    text-align: center;
}

.powerup-count.empty {
    background: rgba(255, 255, 255, 0.2);
}

/* Power-up Notification */
.powerup-notification {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%) scale(0);
    background: rgba(0, 0, 0, 0.9);
    border: 2px solid var(--accent-primary);
    border-radius: var(--border-radius);
    padding: 2rem;
    text-align: center;
    z-index: 3000;
    animation: powerupPop 0.5s ease-out forwards;
}

@keyframes powerupPop {
    0% {
        transform: translate(-50%, -50%) scale(0);
    }

    50% {
        transform: translate(-50%, -50%) scale(1.1);
    }

    100% {
        transform: translate(-50%, -50%) scale(1);
    }
}

.powerup-notification .powerup-icon {
    font-size: 3rem;
    display: block;
    margin-bottom: 0.5rem;
}

.powerup-notification .powerup-name {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--accent-primary);
}

/* ========== Streak Display ========== */
.streak-display {
    background: linear-gradient(135deg, #f59e0b, #ef4444);
    padding: 0.3rem 0.75rem;
    border-radius: var(--border-radius-sm);
    font-weight: 600;
    font-size: 0.9rem;
    animation: streakPulse 1s infinite;
}

@keyframes streakPulse {

    0%,
    100% {
        transform: scale(1);
    }

    50% {
        transform: scale(1.05);
    }
}

.streak-display.hidden {
    display: none;
}

/* ========== Lock Indicator ========== */
.lock-indicator {
    font-size: 0.65rem;
    background: rgba(255, 255, 255, 0.15);
    padding: 0.15rem 0.4rem;
    border-radius: 4px;
    margin-top: 0.2rem;
}

.lock-indicator.unlocked {
    display: none;
}

.difficulty-btn.locked {
    opacity: 0.6;
    cursor: not-allowed;
}

/* ========== Pause Menu Buttons ========== */
.pause-buttons {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    margin-top: 1.5rem;
    width: 100%;
    max-width: 250px;
}

.pause-menu-btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--border-radius-sm);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    background: var(--accent-gradient);
    color: white;
}

.pause-menu-btn:hover {
    transform: scale(1.05);
    filter: brightness(1.1);
}

.pause-menu-btn.secondary {
    background: rgba(255, 255, 255, 0.2);
}

.pause-menu-btn.danger {
    background: linear-gradient(135deg, #ef4444, #dc2626);
}

/* ========== Floating Pause Button ========== */
.floating-pause-btn {
    position: fixed;
    top: 1rem;
    right: 1rem;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    border: none;
    background: rgba(0, 0, 0, 0.6);
    color: white;
    font-size: 1.5rem;
    cursor: pointer;
    z-index: 100;
    transition: var(--transition);
    backdrop-filter: blur(10px);
}

.floating-pause-btn:hover {
    background: rgba(0, 0, 0, 0.8);
    transform: scale(1.1);
}

.floating-pause-btn.hidden {
    display: none;
}

/* ========== Practice & Podium Styles ========== */
.practice-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
    gap: 1rem;
    margin-top: 1rem;
    padding-bottom: 2rem;
    max-height: 400px;
    overflow-y: auto;
}

.practice-card {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--border-radius);
    padding: 1.5rem 1rem;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
}

.practice-card:hover {
    background: rgba(255, 255, 255, 0.15);
    transform: translateY(-5px);
    border-color: var(--accent-primary);
}

.practice-icon {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.practice-name {
    font-size: 0.9rem;
    font-weight: 500;
}

/* Podium Styles */
.podium-container {
    display: flex;
    justify-content: center;
    align-items: flex-end;
    gap: 1rem;
    margin: 2rem 0;
    height: 180px;
}

.podium-spot {
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 80px;
}

.podium-bar {
    width: 100%;
    background: linear-gradient(to top, rgba(255, 255, 255, 0.1), rgba(255, 255, 255, 0.3));
    border-radius: 8px 8px 0 0;
    display: flex;
    align-items: flex-end;
    justify-content: center;
    padding-bottom: 0.5rem;
    font-weight: bold;
    font-size: 1.5rem;
    color: rgba(0, 0, 0, 0.5);
    transition: height 0.5s ease-out;
}

.podium-score {
    font-weight: bold;
    color: var(--accent-secondary);
    margin-bottom: 0.5rem;
    font-size: 0.9rem;
}

.podium-rank-1 .podium-bar {
    height: 120px;
    background: linear-gradient(to top, #ffd700, #ffeb3b);
    box-shadow: 0 0 20px rgba(255, 215, 0, 0.4);
}

.podium-rank-2 .podium-bar {
    height: 90px;
    background: linear-gradient(to top, #c0c0c0, #e0e0e0);
}

.podium-rank-3 .podium-bar {
    height: 60px;
    background: linear-gradient(to top, #cd7f32, #f4a460);
}