/* Import Font chữ hiện đại */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;600;700&display=swap');

:root {
    --bg-color: #0f172a;
    --card-bg: rgba(30, 41, 59, 0.7);
    --accent-color: #38bdf8;
    --text-main: #f1f5f9;
    --text-dim: #94a3b8;
    --success: #4ade80;
    --warning: #fbbf24;
    --danger: #f87171;
    --glass-border: rgba(255, 255, 255, 0.1);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    transition: all 0.3s ease;
}

body {
    font-family: 'Inter', sans-serif;
    background: radial-gradient(circle at top right, #1e293b, #0f172a);
    color: var(--text-main);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 40px 20px;
}

h1, h2, h3 {
    letter-spacing: -0.025em;
    margin-bottom: 20px;
    background: linear-gradient(to right, #38bdf8, #818cf8);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

/* Container chung phong cách kính mờ */
.glass-card {
    background: var(--card-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
    border-radius: 24px;
    padding: 30px;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    width: 100%;
    max-width: 800px;
    margin-bottom: 30px;
}

/* Camera UI */
.video-container {
    position: relative;
    width: 100%;
    aspect-ratio: 16/9;
    background: #000;
    border-radius: 16px;
    overflow: hidden;
    border: 2px solid var(--glass-border);
}

video, canvas {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

/* Timer & Status */
#timer-text, #remaining-time {
    font-size: 3.5rem;
    font-weight: 700;
    font-variant-numeric: tabular-nums;
    color: var(--accent-color);
    text-shadow: 0 0 20px rgba(56, 189, 248, 0.3);
    margin: 10px 0;
}

.status-badge {
    display: inline-block;
    padding: 6px 16px;
    border-radius: 9999px;
    font-size: 0.875rem;
    font-weight: 600;
    background: rgba(56, 189, 248, 0.1);
    border: 1px solid rgba(56, 189, 248, 0.2);
}

/* Battery UI Pro */
.battery-wrapper {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 5px;
    margin: 25px 0;
}

.battery-body {
    width: 160px;
    height: 80px;
    border: 4px solid #475569;
    border-radius: 14px;
    padding: 6px;
    background: #0f172a;
    position: relative;
}

.battery-head {
    width: 8px;
    height: 30px;
    background: #475569;
    border-radius: 0 4px 4px 0;
}

.battery-fill {
    height: 100%;
    border-radius: 8px;
    position: relative;
    overflow: hidden;
}

.battery-fill::after {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background: linear-gradient(rgba(255,255,255,0.2), transparent);
}

.bg-red { background: linear-gradient(to bottom, #f87171, #ef4444); box-shadow: 0 0 20px rgba(239, 68, 68, 0.4); }
.bg-yellow { background: linear-gradient(to bottom, #fbbf24, #f59e0b); box-shadow: 0 0 20px rgba(245, 158, 11, 0.4); }
.bg-green { background: linear-gradient(to bottom, #4ade80, #22c55e); box-shadow: 0 0 20px rgba(34, 197, 94, 0.4); }

/* Admin Dashboard Elements */
.user-list-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 15px;
    margin-top: 20px;
}

.user-card {
    background: rgba(255,255,255,0.03);
    padding: 15px;
    border-radius: 12px;
    border: 1px solid var(--glass-border);
    cursor: pointer;
    text-align: center;
}

.user-card:hover {
    background: rgba(255,255,255,0.08);
    transform: translateY(-5px);
    border-color: var(--accent-color);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 15px;
    margin: 20px 0;
}

.stat-item {
    background: rgba(0,0,0,0.2);
    padding: 15px;
    border-radius: 12px;
    text-align: center;
}

.stat-value { font-size: 1.5rem; font-weight: 700; color: var(--accent-color); }
.stat-label { font-size: 0.75rem; color: var(--text-dim); text-transform: uppercase; }

/* Form & Buttons */
input[type="number"] {
    background: #1e293b;
    border: 1px solid var(--glass-border);
    color: white;
    padding: 8px 12px;
    border-radius: 8px;
    outline: none;
    margin-bottom: 10px;
}

button {
    background: linear-gradient(to bottom right, #38bdf8, #2563eb);
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: 12px;
    font-weight: 600;
    cursor: pointer;
    box-shadow: 0 4px 14px 0 rgba(0, 118, 255, 0.39);
}

button:hover {
    transform: scale(1.02);
    box-shadow: 0 6px 20px rgba(0, 118, 255, 0.23);
}

/* Nút Login Facebook đặc thù */
#loginBtn {
    background: #1877F2;
    display: flex;
    align-items: center;
    gap: 10px;
}