:root {
    --bg-main: #0a0b10;
    --glass-bg: rgba(255, 255, 255, 0.03);
    --glass-border: rgba(255, 255, 255, 0.08);
    --accent: #5b5dfa;
    --accent-glow: rgba(91, 93, 250, 0.3);
    --text-primary: #ffffff;
    --text-secondary: rgba(255, 255, 255, 0.6);
    --blur: 12px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Vazirmatn', 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
}

body {
    background: var(--bg-main);
    color: var(--text-primary);
    min-height: 100vh;
    background-image: 
        radial-gradient(circle at 20% 30%, #1a1b3a 0%, transparent 40%),
        radial-gradient(circle at 80% 70%, #15162c 0%, transparent 40%);
}

.spinner-container {
    position: absolute;
    left: 120px;
    top: 50%;
    transform: translateY(-50%);
    pointer-events: none;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 2rem;
}

header {
    text-align: center;
    margin-bottom: 4rem;
    margin-top: 2rem;
}

h1 {
    font-size: 2.5rem;
    font-weight: 800;
    background: linear-gradient(to right, #fff, #888);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    letter-spacing: -0.02em;
}

/* Reset overflow for 100% reliable sticky support */
html, body {
    overflow: visible;
}

/* 900px Centered Sticky Research Bar */
.sticky-wrapper {
    position: -webkit-sticky; 
    position: sticky !important;
    top: 0;
    z-index: 1000;
    width: 100%;
    max-width: 900px;
    margin: 0 auto;
    background: rgba(10, 11, 16, 0.95);
    backdrop-filter: blur(25px);
    -webkit-backdrop-filter: blur(25px);
    border-bottom: 1px solid var(--glass-border);
    padding: 1.5rem 0;
    box-shadow: 0 4px 20px rgba(0,0,0,0.4);
}

.search-box {
    position: relative;
    margin-bottom: 1.5rem;
    display: flex;
    gap: 10px;
}

.search-btn {
    background: var(--accent);
    color: white;
    border: none;
    padding: 0 2rem;
    border-radius: 16px;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 4px 15px var(--accent-glow);
    white-space: nowrap;
    display: flex;
    align-items: center;
    justify-content: center;
    min-width: 100px;
}

.search-btn:hover {
    filter: brightness(1.1);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px var(--accent-glow);
}

.search-btn:active {
    transform: translateY(0);
}

.search-btn:disabled {
    background: rgba(255, 255, 255, 0.1);
    color: var(--text-secondary);
    cursor: wait;
    transform: none;
    box-shadow: none;
    pointer-events: none;
}

.stop-mode .search-btn {
    background: #ef4444;
    box-shadow: 0 4px 15px rgba(239, 68, 68, 0.4);
    animation: activePulse 2s infinite;
}

@keyframes activePulse {
    0% { box-shadow: 0 4px 15px rgba(239, 68, 68, 0.4); }
    50% { box-shadow: 0 4px 25px rgba(239, 68, 68, 0.6); }
    100% { box-shadow: 0 4px 15px rgba(239, 68, 68, 0.4); }
}

.stop-mode .search-btn:hover {
    box-shadow: 0 6px 20px rgba(239, 68, 68, 0.6);
}

input[type="text"] {
    flex: 1;
    padding: 1.2rem 1.5rem;
    font-size: 1.1rem;
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    color: white;
    backdrop-filter: blur(var(--blur));
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 4px 24px rgba(0,0,0,0.2);
}

input[type="text"]:focus {
    outline: none;
    border-color: var(--accent);
    background: rgba(255, 255, 255, 0.05);
    box-shadow: 0 0 20px var(--accent-glow);
}

.results-container {
    display: flex;
    flex-direction: column;
    gap: 3rem;
    animation: fadeInUp 0.5s ease-out;
}

.results-section {
    display: flex;
    flex-direction: column;
    gap: 1.2rem;
}

.section-title {
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-secondary);
    padding-bottom: 0.5rem;
    border-bottom: 1px solid var(--glass-border);
    margin-bottom: 0.5rem;
}

.video-card {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 20px;
    padding: 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    backdrop-filter: blur(var(--blur));
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.video-card:hover {
    transform: translateX(5px);
    background: rgba(255, 255, 255, 0.05);
}

.keyword-border { border-left: 4px solid #4ade80; }
.semantic-border { border-left: 4px solid var(--accent); }

.video-info h3 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 0.4rem;
}

.match-score {
    font-size: 0.85rem;
    font-weight: 500;
}

.semantic-score { color: var(--accent); }

.video-actions {
    margin-top: 1rem;
    flex-shrink: 0;
}

.summary-box {
    margin-top: 1rem;
    padding: 0.8rem 1rem;
    background: rgba(255, 255, 255, 0.02);
    border-radius: 12px;
    border: 1px solid var(--glass-border);
    transition: max-height 0.3s ease;
}

/* Short Mode Logic */
.mode-short .summary-box {
    display: none;
}
.mode-short .video-card {
    padding: 1rem 1.5rem;
}
.mode-short .video-actions {
    margin-top: 0;
}
.mode-short .results-container {
    gap: 1rem;
}
.mode-short .results-section {
    gap: 0.5rem;
}

/* Collapsible Headers */
.collapsible-header {
    cursor: pointer;
    user-select: none;
    transition: opacity 0.2s;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.collapsible-header:hover {
    opacity: 0.8;
}
.collapsible-header::after {
    content: '▾';
    font-size: 1.2rem;
    transition: transform 0.3s;
}
.collapsed .collapsible-header::after {
    transform: rotate(-90deg);
}
.collapsed .section-content {
    display: none;
}

.summary-title {
    font-size: 0.8rem;
    font-weight: 700;
    text-transform: uppercase;
    color: var(--accent);
    margin-bottom: 0.5rem;
    display: block;
    letter-spacing: 0.05em;
}

.summary-list {
    list-style: none;
    font-size: 0.9rem;
    line-height: 1.5;
    color: var(--text-secondary);
}

.summary-item {
    position: relative;
    padding-right: 1.2rem;
    margin-bottom: 0.3rem;
}

.summary-item::before {
    content: "•";
    position: absolute;
    right: 0;
    color: var(--accent);
    font-weight: bold;
}

.watch-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.6rem 1.2rem;
    background: var(--accent);
    color: white;
    text-decoration: none;
    border-radius: 12px;
    font-size: 0.9rem;
    font-weight: 600;
    transition: all 0.2s ease;
    white-space: nowrap;
    min-width: 140px;
}

.watch-btn svg { width: 18px; height: 18px; }
.watch-btn:hover { 
    filter: brightness(1.2);
    transform: scale(1.05);
}

/* Skeleton Loader */
.skeleton-loader {
    display: flex;
    flex-direction: column;
    gap: 1.2rem;
}

.skeleton-card {
    height: 100px;
    background: linear-gradient(90deg, var(--glass-bg) 25%, rgba(255,255,255,0.05) 50%, var(--glass-bg) 75%);
    background-size: 200% 100%;
    animation: shimmer 1.5s infinite;
    border-radius: 20px;
}

.loading-text {
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-top: 1rem;
    font-style: italic;
}

@keyframes shimmer {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}

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

@keyframes spin {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

/* Format Toggle Controls */
.format-controls {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 1.5rem;
    margin-top: 0.5rem;
    padding-top: 1rem;
    border-top: 1px solid rgba(255,255,255,0.05);
}

.format-btn {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--glass-border);
    color: var(--text-secondary);
    padding: 0.6rem 1.5rem;
    border-radius: 20px;
    cursor: pointer;
    font-size: 0.85rem;
    font-weight: 500;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.format-btn:hover {
    background: rgba(255, 255, 255, 0.08);
    border-color: var(--accent);
    color: white;
    transform: translateY(-2px);
}

.format-btn.active {
    background: var(--accent);
    color: white;
    border-color: var(--accent);
    box-shadow: 0 0 15px var(--accent-glow);
}

/* AI Confidence Color Tiers */
.conf-high { color: #a78bfa !important; }
.conf-med  { color: #60a5fa !important; }
.conf-low  { color: #94a3b8 !important; }