/* style.css - Theme: Digital Tactical HUD (Quân sự số hóa) */
@import url('https://fonts.googleapis.com/css2?family=Roboto:wght@300;400;500;700;900&family=Orbitron:wght@500;700&display=swap');

:root {
    --army-dark: #1a202c;       /* Nền tối chủ đạo */
    --army-green: #2F4F4F;      /* Xanh rêu đậm */
    --army-accent: #4ade80;     /* Xanh lá neon (tín hiệu số) */
    --army-gold: #fbbf24;       /* Vàng quân hiệu */
    --panel-bg: rgba(30, 41, 59, 0.85); /* Nền kính mờ */
    --text-primary: #e2e8f0;
}

body {
    font-family: 'Roboto', sans-serif;
    background-color: #0f172a; /* Slate 900 */
    background-image: 
        radial-gradient(circle at 10% 20%, rgba(47, 79, 79, 0.4) 0%, transparent 20%),
        radial-gradient(circle at 90% 80%, rgba(206, 17, 38, 0.1) 0%, transparent 20%);
    color: var(--text-primary);
    overflow-x: hidden;
}

/* Font kỹ thuật số cho tiêu đề */
.font-tech { font-family: 'Orbitron', sans-serif; letter-spacing: 1px; }

/* Scrollbar tùy chỉnh */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: #0f172a; }
::-webkit-scrollbar-thumb { background: #475569; border-radius: 3px; }

/* Hiệu ứng kính mờ (Glassmorphism) */
.glass-panel {
    background: var(--panel-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.5);
}

/* Nút bấm kiểu HUD */
.btn-hud {
    background: linear-gradient(180deg, rgba(55, 65, 81, 0.8) 0%, rgba(31, 41, 55, 0.9) 100%);
    border: 1px solid rgba(74, 222, 128, 0.3);
    color: var(--army-accent);
    text-transform: uppercase;
    font-family: 'Orbitron', sans-serif;
    letter-spacing: 1px;
    position: relative;
    overflow: hidden;
    transition: all 0.3s ease;
}
.btn-hud:hover {
    background: rgba(74, 222, 128, 0.1);
    border-color: var(--army-accent);
    box-shadow: 0 0 15px rgba(74, 222, 128, 0.3);
    text-shadow: 0 0 5px var(--army-accent);
}

/* Card bài giảng */
.card-tech {
    background: linear-gradient(145deg, #1e293b, #0f172a);
    border: 1px solid #334155;
    position: relative;
    transition: 0.3s;
}
.card-tech::before {
    content: ''; position: absolute; top: 0; left: 0; width: 100%; height: 2px;
    background: linear-gradient(90deg, transparent, var(--army-gold), transparent);
    opacity: 0.5;
}
.card-tech:hover {
    transform: translateY(-5px);
    border-color: var(--army-gold);
    box-shadow: 0 10px 20px rgba(0,0,0,0.5);
}
.card-tech:active { transform: scale(0.98); }

/* Animation quét radar */
@keyframes scanline {
    0% { transform: translateY(-100%); }
    100% { transform: translateY(100%); }
}
.scan-effect { position: absolute; inset: 0; pointer-events: none; overflow: hidden; opacity: 0.1; }
.scan-effect::after {
    content: ""; position: absolute; inset: 0;
    background: linear-gradient(to bottom, transparent, #4ade80, transparent);
    height: 50%; animation: scanline 4s linear infinite;
}

/* Viewer Container */
.viewer-container { background: #000; height: 100vh; display: flex; flex-direction: column; }