/* BIẾN MÀU MẶC ĐỊNH (SÁNG) */
:root {
    --primary-blue: #1E40AF;
    --primary-teal: #0D9488;
    --soft-blue: #EFF6FF;
    --soft-teal: #F0FDFA;
    --light-gray: #F3F4F6;
    --white: #FFFFFF;
    --text-main: #111827;
    --text-muted: #4B5563;
    --border-color: #E5E7EB;
    --border-light: #BFDBFE;
    --radius-lg: 24px;
    
    /* Biến dùng cho Skeleton */
    --skeleton-bg: #E5E7EB;
    --skeleton-shine: #F3F4F6;
}

/* BIẾN MÀU DARK MODE (PACS THEME) */
body.dark-theme {
    --primary-blue: #60A5FA;
    --primary-teal: #2DD4BF;
    --soft-blue: #1F2937;
    --soft-teal: #1F2937;
    --light-gray: #374151;
    --white: #111827;       /* Nền trang chủ thành xám đen */
    --text-main: #F9FAFB;
    --text-muted: #9CA3AF;
    --border-color: #374151;
    --border-light: #4B5563;
    
    --skeleton-bg: #374151;
    --skeleton-shine: #4B5563;
}

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

body {
    font-family: 'Inter', sans-serif;
    color: var(--text-main);
    background-color: var(--white);
    line-height: 1.6;
    transition: background-color 0.4s ease, color 0.4s ease;
}

/* NAVBAR */
.navbar {
    display: flex; justify-content: space-between; align-items: center;
    padding: 16px 5%; background: var(--white);
    position: relative; z-index: 100;
    border-bottom: 1px solid var(--border-color);
}
.logo { font-size: 22px; font-weight: 700; color: var(--primary-blue); }
.logo span { color: var(--primary-teal); }
.navbar nav a { text-decoration: none; color: var(--text-muted); margin-left: 24px; font-weight: 500; font-size: 15px;}
.navbar nav a:hover { color: var(--primary-blue); }

.theme-toggle-btn {
    background: none; border: none; cursor: pointer;
    color: var(--text-muted); width: 36px; height: 36px;
    display: flex; align-items: center; justify-content: center;
    border-radius: 50%; transition: background 0.3s;
}
.theme-toggle-btn:hover { background: var(--light-gray); color: var(--text-main); }
.theme-toggle-btn svg { width: 20px; height: 20px; }

/* BENTO GRID */
.hero-bento-section { padding: 24px 5% 48px; max-width: 1400px; margin: 0 auto; }
.bento-grid { display: grid; grid-template-columns: 1fr 1fr; grid-template-rows: 1fr 1fr; gap: 24px; min-height: 80vh; }

.bento-panel {
    border-radius: var(--radius-lg); padding: 32px;
    display: flex; flex-direction: column; justify-content: space-between;
    overflow: hidden; position: relative;
    transition: transform 0.3s ease, box-shadow 0.3s ease, background-color 0.4s ease;
    cursor: pointer;
}
.bento-panel:hover { transform: translateY(-4px); box-shadow: 0 20px 40px rgba(0,0,0,0.06); }

/* Backgrounds sử dụng CSS Variables để tự động đổi màu */
.bg-soft-blue { background-color: var(--soft-blue); }
.bg-soft-teal { background-color: var(--soft-teal); }
.bg-white { background-color: var(--white); }
.outline-border { border: 1px solid var(--border-color); }

/* PANEL CONTENT */
.panel-header { z-index: 2; position: relative; margin-bottom: 24px; pointer-events: none; }
.panel-header a { pointer-events: auto; }

.badge { display: inline-block; padding: 6px 12px; border-radius: 20px; font-size: 12px; font-weight: 600; text-transform: uppercase; margin-bottom: 16px; }
.badge-blue { background-color: rgba(96, 165, 250, 0.15); color: var(--primary-blue); }
.badge-teal { background-color: rgba(45, 212, 191, 0.15); color: var(--primary-teal); }
.badge-gray { background-color: rgba(156, 163, 175, 0.15); color: var(--text-muted); }

.panel-title { font-size: 26px; font-weight: 700; color: var(--text-main); line-height: 1.3; margin-bottom: 12px; transition: color 0.4s; }
.panel-title span { color: var(--primary-blue); }
.panel-title.teal span { color: var(--primary-teal); }

.panel-desc { font-size: 15px; color: var(--text-muted); max-width: 90%; transition: color 0.4s; }

.cta-link { display: inline-flex; align-items: center; gap: 6px; margin-top: 16px; font-size: 15px; font-weight: 600; text-decoration: none; }
.cta-link.blue { color: var(--primary-blue); }
.cta-link.teal { color: var(--primary-teal); }
.cta-link svg { width: 18px; height: 18px; transition: transform 0.2s; }
.bento-panel:hover .cta-link svg { transform: translateX(4px); }

/* VISUAL MOCKUPS */
.panel-visual { position: relative; z-index: 1; display: flex; justify-content: center; align-items: flex-end; flex-grow: 1; margin-top: 20px; pointer-events: none; }

/* Các định dạng Mockup (Sử dụng Var để tự thích ứng Dark Mode) */
.quiz-mockup { width: 100%; background: var(--white); padding: 16px; border-radius: 12px 12px 0 0; border: 1px solid var(--border-color); }
.quiz-bar { height: 6px; background: var(--border-color); border-radius: 3px; margin-bottom: 16px; overflow: hidden; }
.quiz-progress { height: 100%; width: 40%; background: var(--primary-blue); }
.quiz-options { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; }
.quiz-opt { padding: 8px; background: var(--light-gray); border-radius: 6px; font-size: 12px; font-weight: 500; color: var(--text-main); border: 1px solid transparent; }
.quiz-opt.active { background: rgba(96, 165, 250, 0.1); color: var(--primary-blue); border-color: var(--primary-blue); }

.mri-grid-light { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; width: 85%; }
.mri-item-light { background: var(--white); border: 1px solid var(--border-color); height: 80px; border-radius: 10px; display: flex; align-items: flex-end; padding: 12px; color: var(--primary-blue); font-size: 13px; font-weight: 600; }

.protocol-list-light { width: 95%; background: var(--soft-teal); border-radius: 12px 12px 0 0; padding: 20px; border: 1px solid var(--border-color); }
.proto-row-light { display: flex; justify-content: space-between; align-items: center; padding: 12px 0; border-bottom: 1px dashed var(--border-color); font-size: 13px; }
.proto-row-light:last-child { border: none; padding-bottom: 0; }
.proto-label-light { font-weight: 600; color: var(--text-main); display: flex; align-items: center; gap: 8px; }
.proto-val-light { color: var(--primary-teal); font-family: monospace; font-weight: 600; }
.check-icon { color: var(--primary-teal); width: 16px; height: 16px; }

/* =========================================
   HIỆU ỨNG SKELETON LOADING
   ========================================= */
.skeleton-wrapper { width: 100%; height: 100%; display: flex; flex-direction: column; }
.skeleton {
    background: linear-gradient(90deg, var(--skeleton-bg) 25%, var(--skeleton-shine) 50%, var(--skeleton-bg) 75%);
    background-size: 200% 100%;
    animation: skeleton-loading 1.5s infinite linear;
    border-radius: 8px;
}
@keyframes skeleton-loading {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}
.skel-badge { width: 100px; height: 24px; border-radius: 20px; margin-bottom: 16px; }
.skel-title { width: 70%; height: 32px; margin-bottom: 12px; }
.skel-desc { width: 90%; height: 16px; margin-bottom: 8px; }
.skel-visual { width: 100%; flex-grow: 1; margin-top: 40px; border-radius: 12px 12px 0 0; }

/* RESPONSIVE */
@media (max-width: 900px) {
    .navbar nav { display: none; }
    .hero-bento-section { padding: 16px 5% 32px; }
    .bento-grid { grid-template-columns: 1fr; grid-template-rows: auto; gap: 16px; }
    .bento-panel { padding: 24px; }
    .panel-title { font-size: 22px; }
    .quiz-options { grid-template-columns: 1fr; }
    .mri-grid-light { width: 100%; gap: 8px; }
    .mri-item-light { height: 70px; }
    .protocol-list-light { width: 100%; }
}