:root {
    --bg-primary: #0d1117;
    --bg-secondary: #161b22;
    --bg-tertiary: #21262d;
    --text-primary: #c9d1d9;
    --text-secondary: #8b949e;
    --text-muted: #6e7681;
    --border-color: #30363d;
    --accent-green: #238636;
    --accent-green-hover: #2ea043;
    --accent-orange: #f0883e;
    --accent-red: #f85149;
    --accent-blue: #58a6ff;
    --card-bg: #161b22;
    --card-hover: #1f242b;
}

* {
    box-sizing: border-box;
}

body {
    background-color: var(--bg-primary);
    color: var(--text-primary);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans", Helvetica, Arial, sans-serif;
    min-height: 100vh;
}

/* Navbar */
.navbar {
    background-color: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    padding: 0.75rem 0;
}

.navbar-brand {
    font-weight: 600;
    font-size: 1.25rem;
}

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

.lang-switch {
    display: flex;
    background-color: var(--bg-tertiary);
    border-radius: 6px;
    padding: 2px;
}

.lang-btn {
    color: var(--text-secondary);
    background: transparent;
    border: none;
    padding: 4px 12px;
    font-size: 0.875rem;
    border-radius: 4px;
    transition: all 0.2s;
}

.lang-btn:hover {
    color: var(--text-primary);
}

.lang-btn.active {
    background-color: var(--bg-secondary);
    color: var(--text-primary);
}

.github-link {
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    text-decoration: none;
    transition: color 0.2s;
}

.github-link:hover {
    color: var(--text-primary);
}

/* Main content */
.main-content {
    padding: 2rem 0;
}

.min-vh-80 {
    min-height: 80vh;
}

/* Hero section */
.hero-content {
    padding: 2rem 0;
}

.hero-title {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.hero-features {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.feature-item {
    display: flex;
    gap: 1rem;
    align-items: flex-start;
}

.feature-icon {
    width: 48px;
    height: 48px;
    background-color: var(--bg-tertiary);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--accent-green);
    flex-shrink: 0;
}

.feature-text {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.feature-text strong {
    color: var(--text-primary);
    font-size: 1rem;
}

.feature-text span {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.hero-actions .btn-primary {
    background-color: var(--accent-green);
    border-color: var(--accent-green);
    padding: 0.75rem 2rem;
    font-weight: 500;
}

.hero-actions .btn-primary:hover {
    background-color: var(--accent-green-hover);
    border-color: var(--accent-green-hover);
}

.hero-illustration {
    display: flex;
    justify-content: center;
    align-items: center;
}

.winter-svg {
    width: 100%;
    max-width: 400px;
    height: auto;
}

/* Browse page */
.browse-header {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

@media (min-width: 768px) {
    .browse-header {
        flex-direction: row;
        justify-content: space-between;
        align-items: center;
    }
}

.page-title {
    font-size: 2rem;
    font-weight: 600;
    margin: 0;
}

.search-container {
    max-width: 300px;
    width: 100%;
}

.search-input {
    background-color: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 0.5rem 1rem;
}

.search-input:focus {
    background-color: var(--bg-tertiary);
    border-color: var(--accent-blue);
    color: var(--text-primary);
    box-shadow: 0 0 0 3px rgba(88, 166, 255, 0.15);
}

.search-input::placeholder {
    color: var(--text-muted);
}

/* Groups grid */
.groups-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 1rem;
}

.group-card {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1.5rem;
    cursor: pointer;
    transition: all 0.2s;
    text-decoration: none;
    color: inherit;
}

.group-card:hover {
    background-color: var(--card-hover);
    border-color: var(--accent-blue);
    transform: translateY(-2px);
}

.group-card-icon {
    width: 64px;
    height: 64px;
    background-color: var(--bg-tertiary);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1rem;
}

.group-card-icon svg {
    width: 32px;
    height: 32px;
    color: var(--accent-green);
}

.group-card-title {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.group-card-count {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* Tests grid */
.tests-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1rem;
}

.test-card-link {
    text-decoration: none;
    color: inherit;
}

.test-card-item {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1.5rem;
    transition: all 0.2s;
    display: flex;
    gap: 1rem;
    align-items: flex-start;
}

.test-card-item:hover {
    background-color: var(--card-hover);
    border-color: var(--accent-green);
}

.test-card-icon {
    width: 48px;
    height: 48px;
    flex-shrink: 0;
    display: flex;
    align-items: center;
    justify-content: center;
}

.test-card-icon img {
    width: 100%;
    height: 100%;
    object-fit: contain;
}

.test-card-content {
    flex: 1;
    min-width: 0;
}

.test-card-title {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.test-card-desc {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

.test-card-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.tag {
    background-color: var(--bg-tertiary);
    color: var(--text-secondary);
    padding: 0.25rem 0.5rem;
    border-radius: 4px;
    font-size: 0.75rem;
}

.group-title {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
}

.no-results {
    text-align: center;
    padding: 3rem;
    color: var(--text-secondary);
}

/* Test page */
.test-container {
    min-height: calc(100vh - 60px);
}

.progress-container {
    max-width: 800px;
    margin: 2rem auto 0;
    padding: 1rem 1.5rem;
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
}

.progress-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.75rem;
}

.progress-question {
    color: var(--text-primary);
    font-size: 0.9375rem;
    font-weight: 500;
}

.progress-answered {
    display: flex;
    align-items: center;
    gap: 0.375rem;
    color: var(--accent-green);
    font-size: 0.875rem;
    font-weight: 600;
}

.progress-answered svg {
    color: var(--accent-green);
}

.progress-bar-wrapper {
    position: relative;
}

.progress-bar-track {
    height: 8px;
    background-color: var(--bg-tertiary);
    border-radius: 8px;
    overflow: hidden;
}

.progress-bar-fill {
    height: 100%;
    width: 0%;
    background-color: var(--accent-green);
    border-radius: 8px;
    transition: width 0.4s ease-out;
}

.test-content {
    padding: 2rem 0;
}

.loading-state {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 400px;
}

.test-card {
    max-width: 800px;
    margin: 0 auto;
}

.test-title {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.test-description {
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.question-container {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 2rem;
    margin-bottom: 1.5rem;
}

.question-text {
    font-size: 1.25rem;
    font-weight: 500;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.answers-list {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.answer-btn {
    background-color: var(--bg-tertiary);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    padding: 1rem 1.25rem;
    text-align: left;
    color: var(--text-primary);
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.2s;
    width: 100%;
}

.answer-btn:hover:not(:disabled) {
    border-color: var(--accent-blue);
    background-color: var(--card-hover);
}

.answer-btn.selected {
    border-color: var(--accent-blue);
    background-color: rgba(88, 166, 255, 0.1);
}

.answer-btn.correct {
    border-color: var(--accent-green);
    background-color: rgba(35, 134, 54, 0.15);
}

.answer-btn.incorrect {
    border-color: var(--accent-red);
    background-color: rgba(248, 81, 73, 0.15);
}

.answer-btn:disabled {
    cursor: default;
}

.feedback-container {
    margin-top: 1rem;
    padding: 1rem;
    border-radius: 8px;
}

.feedback-container.correct {
    background-color: rgba(35, 134, 54, 0.1);
    border: 1px solid var(--accent-green);
}

.feedback-container.incorrect {
    background-color: rgba(248, 81, 73, 0.1);
    border: 1px solid var(--accent-red);
}

.feedback-message {
    font-weight: 600;
    font-size: 1.125rem;
    margin-bottom: 0.5rem;
}

.feedback-container.correct .feedback-message {
    color: var(--accent-green);
}

.feedback-container.incorrect .feedback-message {
    color: var(--accent-red);
}

.explanation {
    color: var(--text-secondary);
    font-size: 0.9375rem;
}

.test-actions {
    display: flex;
    justify-content: flex-end;
    margin-top: 1.5rem;
}

.test-actions .btn-primary {
    background-color: var(--accent-green);
    border-color: var(--accent-green);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.test-actions .btn-primary:hover {
    background-color: var(--accent-green-hover);
    border-color: var(--accent-green-hover);
}

/* Result page */
.result-container {
    max-width: 800px;
    margin: 0 auto;
}

.result-card {
    text-align: center;
}

.result-title {
    font-size: 2rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.test-name {
    color: var(--text-secondary);
    font-size: 1.25rem;
    font-weight: 400;
    margin-bottom: 2rem;
}

.score-container {
    margin: 2rem 0;
}

.score-circle {
    position: relative;
    width: 180px;
    height: 180px;
    margin: 0 auto 1rem;
}

.score-circle svg {
    transform: rotate(-90deg);
    width: 100%;
    height: 100%;
}

.score-bg {
    fill: none;
    stroke: var(--bg-tertiary);
    stroke-width: 8;
}

.score-progress {
    fill: none;
    stroke: var(--accent-green);
    stroke-width: 8;
    stroke-linecap: round;
    stroke-dasharray: 283;
    stroke-dashoffset: 283;
    transition: stroke-dashoffset 1s ease-out;
}

.score-circle.poor .score-progress {
    stroke: var(--accent-red);
}

.score-circle.average .score-progress {
    stroke: var(--accent-orange);
}

.score-circle.good .score-progress,
.score-circle.excellent .score-progress {
    stroke: var(--accent-green);
}

.score-text {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
}

.score-value {
    font-size: 3rem;
    font-weight: 700;
    color: var(--text-primary);
}

.score-percent {
    font-size: 1.5rem;
    color: var(--text-secondary);
}

.score-message {
    font-size: 1.25rem;
    font-weight: 600;
    margin-top: 0.5rem;
}

.score-message.excellent { color: var(--accent-green); }
.score-message.good { color: var(--accent-green); }
.score-message.average { color: var(--accent-orange); }
.score-message.poor { color: var(--accent-red); }

.result-stats {
    display: flex;
    justify-content: center;
    gap: 3rem;
    margin: 2rem 0;
}

.stat-item {
    text-align: center;
}

.stat-value {
    font-size: 2rem;
    font-weight: 700;
    display: block;
}

.stat-item.correct .stat-value {
    color: var(--accent-green);
}

.stat-item.incorrect .stat-value {
    color: var(--accent-red);
}

.stat-label {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.answers-review {
    margin: 2rem 0;
    text-align: left;
}

.answers-review h3 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
}

.review-list {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.review-item {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 1rem;
    display: flex;
    align-items: flex-start;
    gap: 1rem;
}

.review-icon {
    width: 24px;
    height: 24px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.review-item.correct .review-icon {
    background-color: rgba(35, 134, 54, 0.2);
    color: var(--accent-green);
}

.review-item.incorrect .review-icon {
    background-color: rgba(248, 81, 73, 0.2);
    color: var(--accent-red);
}

.review-question {
    color: var(--text-primary);
    font-size: 0.9375rem;
}

.result-actions {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-top: 2rem;
}

.result-actions .btn-primary {
    background-color: var(--accent-green);
    border-color: var(--accent-green);
}

.result-actions .btn-primary:hover {
    background-color: var(--accent-green-hover);
    border-color: var(--accent-green-hover);
}

.result-actions .btn-outline-secondary {
    border-color: var(--border-color);
    color: var(--text-primary);
}

.result-actions .btn-outline-secondary:hover {
    background-color: var(--bg-tertiary);
    border-color: var(--text-secondary);
}

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

.fade-in {
    animation: fadeIn 0.3s ease forwards;
}

/* Go Test Page - Level Selection */
.go-test-page {
    max-width: 600px;
    margin: 0 auto;
}

.test-header {
    text-align: center;
    margin-bottom: 2rem;
}

.test-header-icon {
    width: 64px;
    height: 64px;
    margin: 0 auto 1rem;
}

.test-header-icon img {
    width: 100%;
    height: 100%;
    object-fit: contain;
}

.test-header h1 {
    font-size: 1.75rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.test-header p {
    color: var(--text-secondary);
}

.options-card {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 2rem;
}

.options-card h3 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.level-options {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    margin-bottom: 1.5rem;
}

.level-btn {
    background-color: var(--bg-tertiary);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    padding: 1rem 1.25rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    transition: all 0.2s;
    color: var(--text-primary);
}

.level-btn:hover:not(:disabled) {
    border-color: var(--accent-blue);
    background-color: var(--card-hover);
}

.level-btn.selected {
    border-color: var(--accent-green);
    background-color: rgba(35, 134, 54, 0.15);
}

.level-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.level-name {
    font-weight: 600;
    font-size: 1rem;
}

.level-questions {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.feedback-option {
    margin-bottom: 1.5rem;
    padding: 1rem;
    background-color: var(--bg-tertiary);
    border-radius: 8px;
}

.toggle-container {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    cursor: pointer;
}

.toggle-container input {
    display: none;
}

.toggle-slider {
    width: 44px;
    height: 24px;
    background-color: var(--border-color);
    border-radius: 12px;
    position: relative;
    transition: background-color 0.2s;
    flex-shrink: 0;
}

.toggle-slider::after {
    content: '';
    position: absolute;
    width: 18px;
    height: 18px;
    background-color: white;
    border-radius: 50%;
    top: 3px;
    left: 3px;
    transition: transform 0.2s;
}

.toggle-container input:checked + .toggle-slider {
    background-color: var(--accent-green);
}

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

.toggle-label {
    color: var(--text-primary);
    font-size: 0.9375rem;
}

.action-buttons {
    display: flex;
    justify-content: space-between;
    gap: 1rem;
}

.action-buttons .btn {
    flex: 1;
    padding: 0.75rem 1.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.action-buttons .btn-secondary {
    background-color: var(--bg-tertiary);
    border-color: var(--border-color);
    color: var(--text-primary);
}

.action-buttons .btn-secondary:hover {
    background-color: var(--card-hover);
    border-color: var(--text-secondary);
}

.action-buttons .btn-primary {
    background-color: var(--accent-green);
    border-color: var(--accent-green);
}

.action-buttons .btn-primary:hover:not(:disabled) {
    background-color: var(--accent-green-hover);
    border-color: var(--accent-green-hover);
}

.action-buttons .btn-primary:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

/* Level badge for test page */
.level-badge {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    margin-left: 0.5rem;
}

.level-badge.junior {
    background-color: rgba(35, 134, 54, 0.2);
    color: var(--accent-green);
}

.level-badge.middle {
    background-color: rgba(240, 136, 62, 0.2);
    color: var(--accent-orange);
}

.level-badge.senior {
    background-color: rgba(248, 81, 73, 0.2);
    color: var(--accent-red);
}

/* Responsive */
@media (max-width: 768px) {
    .hero-title {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

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

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

    .result-stats {
        flex-direction: column;
        gap: 1rem;
    }

    .result-actions {
        flex-direction: column;
    }

    .result-actions .btn {
        width: 100%;
    }
}