:root {
    --bg-color: #0f172a;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --glass-bg: rgba(30, 41, 59, 0.7);
    --glass-border: rgba(255, 255, 255, 0.1);
    --accent-color: #3b82f6;
    --accent-glow: rgba(59, 130, 246, 0.5);
    
    /* Category Colors */
    --cat-tech: #10b981;
    --cat-ent: #f43f5e;
    --cat-social: #f59e0b;
    --cat-lifestyle: #8b5cf6;
    --cat-sports: #06b6d4;
    --cat-economy: #eab308;
    --cat-default: #64748b;
}

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

body {
    font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, system-ui, Roboto, 'Helvetica Neue', 'Segoe UI', 'Apple SD Gothic Neo', 'Noto Sans KR', 'Malgun Gothic', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    min-height: 100vh;
    overflow-x: hidden;
    position: relative;
}

/* Background Effects */
.background-effects {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: -1;
    overflow: hidden;
}

.glow-orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(100px);
    opacity: 0.5;
    animation: float 20s infinite alternate;
}

.orb-1 {
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, rgba(59,130,246,0.4) 0%, rgba(0,0,0,0) 70%);
    top: -100px;
    left: -100px;
}

.orb-2 {
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, rgba(139,92,246,0.3) 0%, rgba(0,0,0,0) 70%);
    bottom: -150px;
    right: -100px;
    animation-delay: -10s;
}

@keyframes float {
    0% { transform: translate(0, 0) scale(1); }
    100% { transform: translate(50px, 50px) scale(1.1); }
}

/* Layout */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

/* Glass Header */
.glass-header {
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    padding: 1.5rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.2);
}

.logo-area {
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo-icon {
    color: var(--accent-color);
    font-size: 2rem;
    filter: drop-shadow(0 0 8px var(--accent-glow));
}

h1 {
    font-size: 1.8rem;
    font-weight: 700;
    letter-spacing: -0.5px;
}

.meta-info {
    display: flex;
    align-items: center;
    gap: 16px;
}

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

.refresh-btn {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--glass-border);
    color: var(--text-primary);
    width: 40px;
    height: 40px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
}

.refresh-btn:hover {
    background: rgba(255, 255, 255, 0.1);
    transform: rotate(180deg);
}

/* Filters */
.filters-container {
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    padding: 1rem;
    margin-bottom: 2rem;
}

.filter-tabs {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.tab {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid transparent;
    color: var(--text-secondary);
    padding: 0.6rem 1.2rem;
    border-radius: 20px;
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
}

.tab:hover {
    background: rgba(255, 255, 255, 0.1);
    color: var(--text-primary);
}

.tab.active {
    background: var(--accent-color);
    color: #fff;
    box-shadow: 0 0 15px var(--accent-glow);
}

/* Grid */
.trends-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1.5rem;
}

/* Card */
.trend-card {
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    padding: 1.5rem;
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    position: relative;
    overflow: hidden;
    cursor: pointer;
    animation: fadeIn 0.5s ease backwards;
}

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

.trend-card:hover {
    transform: translateY(-5px) scale(1.02);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.4);
    border-color: rgba(255, 255, 255, 0.2);
}

.trend-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
    background-color: var(--cat-default);
    transition: width 0.3s ease;
}

.trend-card:hover::before {
    width: 6px;
}

/* Card Categories */
.trend-card[data-cat="IT/Tech"]::before { background-color: var(--cat-tech); }
.trend-card[data-cat="Entertainment"]::before { background-color: var(--cat-ent); }
.trend-card[data-cat="Social/News"]::before { background-color: var(--cat-social); }
.trend-card[data-cat="Lifestyle"]::before { background-color: var(--cat-lifestyle); }
.trend-card[data-cat="Sports"]::before { background-color: var(--cat-sports); }
.trend-card[data-cat="Economy"]::before { background-color: var(--cat-economy); }

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.category-badge {
    font-size: 0.75rem;
    font-weight: 600;
    padding: 4px 10px;
    border-radius: 12px;
    background: rgba(255, 255, 255, 0.1);
    color: var(--text-secondary);
}

.trend-card[data-cat="IT/Tech"] .category-badge { color: var(--cat-tech); background: rgba(16, 185, 129, 0.1); }
.trend-card[data-cat="Entertainment"] .category-badge { color: var(--cat-ent); background: rgba(244, 63, 94, 0.1); }
.trend-card[data-cat="Social/News"] .category-badge { color: var(--cat-social); background: rgba(245, 158, 11, 0.1); }
.trend-card[data-cat="Lifestyle"] .category-badge { color: var(--cat-lifestyle); background: rgba(139, 92, 246, 0.1); }
.trend-card[data-cat="Sports"] .category-badge { color: var(--cat-sports); background: rgba(6, 182, 212, 0.1); }
.trend-card[data-cat="Economy"] .category-badge { color: var(--cat-economy); background: rgba(234, 179, 8, 0.1); }

.sentiment-badge {
    font-size: 0.7rem;
    font-weight: 700;
    padding: 3px 8px;
    border-radius: 6px;
    display: inline-block;
    margin-left: 8px;
}

.sentiment-pos { background: rgba(16, 185, 129, 0.2); color: #34d399; }
.sentiment-neg { background: rgba(244, 63, 94, 0.2); color: #fb7185; }
.sentiment-neu { background: rgba(148, 163, 184, 0.2); color: #cbd5e1; }

.source-badge {
    font-size: 0.75rem;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    gap: 4px;
}

.card-title {
    font-size: 1.4rem;
    font-weight: 700;
    margin-bottom: 1rem;
    line-height: 1.4;
    word-break: keep-all;
}

.card-footer {
    display: flex;
    justify-content: flex-end;
    margin-top: auto;
}

.search-link {
    color: var(--text-secondary);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.85rem;
    transition: color 0.2s;
}

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

/* Responsive */
@media (max-width: 768px) {
    .container {
        padding: 1rem;
    }
    
    .glass-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }
    
    .meta-info {
        width: 100%;
        justify-content: space-between;
    }
}

/* HOT Score Badge */
.hot-badge {
    display: inline-flex;
    align-items: center;
    gap: 3px;
    padding: 3px 8px;
    border-radius: 20px;
    font-size: 0.7rem;
    font-weight: 800;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    margin-left: 6px;
}

.hot-super {
    background: linear-gradient(135deg, #ff4500, #ff0080);
    color: white;
    box-shadow: 0 0 12px rgba(255, 69, 0, 0.6);
    animation: pulse-hot 1.5s infinite;
}

.hot-hot {
    background: linear-gradient(135deg, #ff8c00, #ff4500);
    color: white;
    box-shadow: 0 0 8px rgba(255, 140, 0, 0.5);
}

.hot-warm {
    background: linear-gradient(135deg, #3b82f6, #06b6d4);
    color: white;
}

@keyframes pulse-hot {
    0%, 100% { box-shadow: 0 0 12px rgba(255, 69, 0, 0.6); transform: scale(1); }
    50% { box-shadow: 0 0 20px rgba(255, 0, 128, 0.8); transform: scale(1.05); }
}

/* HOT Score Bar */
.hot-score-bar {
    width: 100%;
    height: 3px;
    background: rgba(255,255,255,0.1);
    border-radius: 2px;
    margin-top: 8px;
    overflow: hidden;
}

.hot-score-fill {
    height: 100%;
    border-radius: 2px;
    transition: width 0.8s ease;
}

/* Auto-refresh countdown */
.refresh-countdown {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.8rem;
    color: var(--text-secondary);
    padding: 4px 10px;
    background: rgba(255,255,255,0.05);
    border-radius: 20px;
    border: 1px solid var(--glass-border);
}

.countdown-dot {
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: #10b981;
    animation: blink 2s infinite;
}

@keyframes blink {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.2; }
}