:root {
    --primary-color: #e65100; /* Dark Orange */
    --primary-light: #3e2723; /* Darker orange/brown for hover backgrounds */
    --bg-color: #000000; /* True Black */
    --body-bg: #121212; /* Dark Grey for body */
    --card-bg: #1e1e1e; /* Dark Grey for cards */
    --card-hover-bg: #2a2a2a;
    --text-main: #ffffff;
    --text-muted: #a0a0a0;
    --border-color: #333333;
    --accent-color: #ff9800; /* Lighter Orange for accents */
    --danger-color: #ff3b30; /* Keep intensity colors */
    --success-color: #34c759;
    --warning-color: #ff9500;
    --card-shadow: 0 4px 20px rgba(0, 0, 0, 0.5);
    --hover-shadow: 0 8px 30px rgba(230, 81, 0, 0.2);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Inter', 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--body-bg);
    color: var(--text-main);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

#app {
    max-width: 1400px;
    margin: 0 auto;
    min-height: 100vh;
    padding: 20px;
}

.page {
    display: none;
    animation: fadeIn 0.3s ease-in-out;
}

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

.page.active {
    display: block;
}

/* Home Page Layout with Sidebar */
.title-bar {
    text-align: center;
    padding: 40px 0;
}

.title-bar h1 {
    font-size: 3rem;
    font-weight: 800;
    color: var(--primary-color);
    letter-spacing: -0.02em;
    text-transform: uppercase;
}

.home-layout {
    display: flex;
    gap: 30px;
    margin-top: 20px;
}

.sidebar {
    width: 280px;
    flex-shrink: 0;
    background: var(--card-bg);
    border-radius: 24px;
    padding: 24px;
    height: fit-content;
    position: sticky;
    top: 20px;
    border: 1px solid var(--border-color);
}

.sidebar-header {
    margin-bottom: 20px;
    padding-bottom: 15px;
    border-bottom: 1px solid var(--border-color);
}

.sidebar-header h3 {
    font-size: 1.2rem;
    color: var(--primary-color);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.categories {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.cat-btn {
    padding: 12px 20px;
    border-radius: 12px;
    border: none;
    background: transparent;
    color: var(--text-muted);
    cursor: pointer;
    font-size: 0.95rem;
    font-weight: 600;
    text-align: left;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

.cat-btn.active {
    background: var(--primary-color);
    color: white;
    box-shadow: 0 4px 15px rgba(230, 81, 0, 0.3);
}

.cat-btn:hover:not(.active) {
    background: var(--primary-light);
    color: var(--primary-color);
}

.main-content {
    flex: 1;
}

/* Filters Section */
.filters {
    background: var(--card-bg);
    padding: 20px;
    border-radius: 20px;
    margin-bottom: 30px;
    border: 1px solid var(--border-color);
}

.dropdowns {
    display: flex;
    gap: 15px;
    justify-content: flex-start;
}

.dropdowns select {
    padding: 12px 20px;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    background: var(--bg-color);
    color: var(--text-main);
    font-size: 0.95rem;
    font-weight: 500;
    outline: none;
    cursor: pointer;
    min-width: 200px;
    transition: all 0.2s;
}

.dropdowns select:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(230, 81, 0, 0.2);
}

/* Video Grid Layout */
.video-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 30px;
}

.video-card {
    background: var(--card-bg);
    border-radius: 24px;
    overflow: hidden;
    box-shadow: var(--card-shadow);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    cursor: pointer;
    position: relative;
    border: 1px solid var(--border-color);
}

.video-card:hover {
    transform: translateY(-8px);
    border-color: var(--primary-color);
    box-shadow: var(--hover-shadow);
}

.video-thumbnail-wrapper {
    position: relative;
    width: 100%;
    aspect-ratio: 16/9;
    overflow: hidden;
}

.video-card img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.5s ease;
}

.video-card:hover img {
    transform: scale(1.05);
}

.video-info {
    padding: 24px;
}

.video-info h3 {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text-main);
}

/* Difficulty Indicator Bar - KEEP COLORS */
.difficulty-container {
    margin-bottom: 16px;
}

.difficulty-label {
    font-size: 0.75rem;
    font-weight: 700;
    color: var(--text-muted);
    text-transform: uppercase;
    margin-bottom: 6px;
    display: block;
}

.difficulty-bar {
    height: 6px;
    background: #333333;
    border-radius: 3px;
    overflow: hidden;
}

.difficulty-fill {
    height: 100%;
    border-radius: 3px;
    transition: width 0.5s ease-out;
}

.diff-low { width: 33%; background: var(--success-color); }
.diff-medium { width: 66%; background: var(--warning-color); }
.diff-high { width: 100%; background: var(--danger-color); }

.video-meta {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-muted);
    display: flex;
    justify-content: space-between;
}

/* Detail Page Layout */
.nav-bar {
    padding: 30px 0;
}

.back-btn {
    background: var(--primary-light);
    border: 1px solid var(--primary-color);
    color: var(--primary-color);
    font-weight: 700;
    padding: 12px 24px;
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.2s;
}

.back-btn:hover {
    background: var(--primary-color);
    color: white;
}

.detail-container {
    display: flex;
    gap: 40px;
    align-items: flex-start;
}

.left-section {
    flex: 1;
}

#video-player-container {
    width: 100%;
    background: #000;
    border-radius: 32px;
    overflow: hidden;
    aspect-ratio: 16/9;
    box-shadow: 0 10px 40px rgba(0,0,0,0.6);
    margin-bottom: 40px;
    border: 1px solid var(--border-color);
}

#main-video-iframe {
    border: none;
    display: block;
}

/* Workout Overview Styling */
.workout-meta-details {
    margin-bottom: 40px;
    padding: 30px;
    background: var(--card-bg);
    border-radius: 24px;
    border: 1px solid var(--border-color);
}

.workout-meta-details p {
    margin-bottom: 15px;
    font-size: 1rem;
    display: flex;
    align-items: baseline;
}

.meta-label {
    color: var(--primary-color);
    font-weight: 700;
    text-transform: uppercase;
    font-size: 0.85rem;
    min-width: 180px;
    letter-spacing: 0.05em;
}

/* Instruction Sheet Table Style */
.guide-content {
    background: var(--card-bg);
    padding: 40px;
    border-radius: 32px;
    border: 1px solid var(--border-color);
}

.guide-content h2 {
    font-size: 1.75rem;
    margin-bottom: 30px;
    font-weight: 800;
    color: var(--primary-color);
    text-transform: uppercase;
}

.instruction-table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
}

.instruction-table th {
    text-align: left;
    background: var(--body-bg);
    padding: 16px;
    font-weight: 700;
    font-size: 0.9rem;
    color: var(--primary-color);
    text-transform: uppercase;
}

.instruction-table td {
    padding: 20px 16px;
    border-bottom: 1px solid var(--border-color);
    vertical-align: top;
    color: var(--text-main);
}

.step-num {
    font-weight: 800;
    color: var(--accent-color);
    font-size: 1.1rem;
}

/* Comment Area & Sidebar */
.comment-area {
    width: 400px;
    background: var(--card-bg);
    padding: 32px;
    border-radius: 32px;
    border: 1px solid var(--border-color);
    position: sticky;
    top: 20px;
}

.comment-tabs {
    display: flex;
    background: var(--body-bg);
    padding: 6px;
    border-radius: 14px;
    margin-bottom: 24px;
}

.tab-btn {
    flex: 1;
    padding: 12px;
    border: none;
    background: transparent;
    cursor: pointer;
    font-weight: 700;
    font-size: 0.9rem;
    color: var(--text-muted);
    border-radius: 10px;
    transition: all 0.2s;
}

.tab-btn.active {
    background: var(--primary-color);
    color: white;
}

/* Heat-based Tag Cloud */
.tag-cloud {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 30px;
}

.tag {
    padding: 6px 14px;
    background: var(--primary-light);
    border-radius: 100px;
    color: var(--primary-color);
    font-weight: 600;
    transition: all 0.2s;
    border: 1px solid transparent;
}

.tag:hover {
    border-color: var(--primary-color);
    transform: scale(1.1);
}

.tag-heat-high { font-size: 1.1rem; padding: 8px 18px; border: 1px solid var(--primary-color); }
.tag-heat-med { font-size: 0.9rem; }
.tag-heat-low { font-size: 0.75rem; opacity: 0.7; }

.comment-list {
    max-height: 500px;
    overflow-y: auto;
    margin-bottom: 30px;
    padding-right: 10px;
}

.comment-list::-webkit-scrollbar {
    width: 6px;
}

.comment-list::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 3px;
}

.comment-item {
    background: var(--body-bg);
    padding: 20px;
    border-radius: 16px;
    margin-bottom: 16px;
    border: 1px solid var(--border-color);
}

.comment-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
}

.comment-type {
    font-size: 0.7rem;
    padding: 4px 8px;
    border-radius: 6px;
    color: white;
    font-weight: 700;
    text-transform: uppercase;
}

.type-normal { background: var(--success-color); }
.type-abnormality { background: var(--danger-color); }
.type-advice { background: var(--accent-color); }

.comment-actions span {
    transition: color 0.2s;
}

.comment-actions span:hover {
    color: var(--primary-color) !important;
}

/* Comment Form Styles */
.comment-form {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.feedback-types {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
}

.type-btn {
    font-size: 0.75rem;
    padding: 8px 12px;
    border-radius: 10px;
    border: 1px solid var(--border-color);
    background: var(--body-bg);
    color: var(--text-muted);
    cursor: pointer;
    font-weight: 600;
    transition: all 0.2s;
}

.type-btn.active {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

textarea {
    width: 100%;
    height: 100px;
    padding: 16px;
    border-radius: 16px;
    border: 1px solid var(--border-color);
    background: var(--body-bg);
    color: var(--text-main);
    resize: none;
    font-family: inherit;
    font-size: 0.95rem;
    outline: none;
    transition: border-color 0.2s;
}

textarea:focus {
    border-color: var(--primary-color);
}

.publish-btn {
    padding: 14px;
    border-radius: 16px;
    border: none;
    background: var(--primary-color);
    color: white;
    font-weight: 700;
    font-size: 1rem;
    cursor: pointer;
    transition: transform 0.2s, background 0.2s;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.publish-btn:hover {
    background: #bf360c;
    transform: scale(1.02);
}

/* Mobile Adaptation */
@media (max-width: 1100px) {
    .home-layout {
        flex-direction: column;
    }
    
    .sidebar {
        width: 100%;
        position: static;
    }

    .categories {
        flex-direction: row;
        overflow-x: auto;
        padding-bottom: 10px;
    }

    .cat-btn {
        white-space: nowrap;
    }

    .detail-container {
        flex-direction: column;
    }
    
    .comment-area {
        width: 100%;
        position: static;
    }
}

@media (max-width: 640px) {
    #app { padding: 16px; }
    .title-bar h1 { font-size: 2.2rem; }
    .dropdowns { flex-direction: column; }
    .dropdowns select { width: 100%; }
    .video-grid { grid-template-columns: 1fr; }
    .instruction-table th { display: none; }
    .instruction-table td { display: block; padding: 10px 0; border: none; }
    .instruction-table tr { display: block; padding: 20px 0; border-bottom: 1px solid var(--border-color); }
}