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

        :root {
            --ink: #000000;
            --ink-70: #27272a;
            --ink-50: #52525b;
            --ink-30: #a1a1aa;
            --ink-15: #e4e4e7;
            --ink-07: #f4f4f5;
            --white: #ffffff;
            --accent: #000000;
            --success: #000000;
            --success-bg: #f4f4f5;
            --success-bd: #e4e4e7;
            --error: #dc2626;
            --error-bg: #fef2f2;
            --error-bd: #fecaca;
            --warn: #dc2626;
            --warn-bg: #fef2f2;
            --warn-bd: #fecaca;
            --r-xs: 6px;
            --r-sm: 10px;
            --r-md: 14px;
            --r-lg: 20px;
            --transition: all 0.28s cubic-bezier(0.4, 0, 0.2, 1);
            --transition-bounce: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
            --card-shadow: 0 4px 20px rgba(0, 0, 0, 0.05);
            --card-shadow-hover: 0 10px 30px rgba(0, 0, 0, 0.1);
        }

        @media (prefers-color-scheme: dark) {
            :root {
                --ink: #ffffff;
                --ink-70: #e4e4e7;
                --ink-50: #a1a1aa;
                --ink-30: #52525b;
                --ink-15: #27272a;
                --ink-07: #18181b;
                --white: #09090b;
                --accent: #ffffff;
                --success: #ffffff;
                --success-bg: #18181b;
                --success-bd: #27272a;
                --error: #f87171;
                --error-bg: rgba(239, 68, 68, 0.12);
                --error-bd: rgba(239, 68, 68, 0.3);
                --warn: #f87171;
                --warn-bg: rgba(239, 68, 68, 0.12);
                --warn-bd: rgba(239, 68, 68, 0.3);
                --card-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
                --card-shadow-hover: 0 10px 30px rgba(0, 0, 0, 0.6);
            }
        }

        html {
            -webkit-font-smoothing: antialiased;
            scroll-behavior: smooth;
        }

        body {
            font-family: 'Noto Sans Thai', sans-serif;
            background: #f8fafc;
            background-image:
                radial-gradient(circle at top right, rgba(0, 0, 0, 0.015) 0%, transparent 60%),
                radial-gradient(circle at bottom left, rgba(0, 0, 0, 0.02) 0%, transparent 60%);
            color: var(--ink);
            min-height: 100vh;
            overflow-x: hidden;
            position: relative;
            transition: background-color 0.3s ease;
        }

        @media (prefers-color-scheme: dark) {
            body {
                background: #000000;
                background-image: none;
            }
        }

        /* Site Header */
        .site-header {
            background: rgba(255, 255, 255, 0.85);
            backdrop-filter: blur(12px) saturate(190%);
            -webkit-backdrop-filter: blur(12px) saturate(190%);
            border-bottom: 1px solid rgba(13, 17, 23, 0.08);
            position: sticky;
            top: 0;
            z-index: 100;
            transition: var(--transition);
        }

        .header-inner {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 32px;
            height: 70px;
            display: flex;
            align-items: center;
            justify-content: space-between;
            gap: 24px;
        }

        .header-brand {
            display: flex;
            align-items: center;
            gap: 14px;
            text-decoration: none;
        }

        .header-logo {
            width: 36px;
            height: 36px;
            background: var(--white);
            border: 1px solid var(--ink-15);
            border-radius: var(--r-sm);
            padding: 3px;
            display: flex;
            align-items: center;
            justify-content: center;
            flex-shrink: 0;
            transition: var(--transition);
        }

        .header-logo img {
            width: 100%;
            height: 100%;
            object-fit: contain;
            border-radius: calc(var(--r-sm) - 3px);
        }

        .header-brand-text {
            line-height: 1.25;
        }

        .header-brand-name {
            font-size: 14.5px;
            font-weight: 800;
            color: var(--ink);
            letter-spacing: -.01em;
        }

        .header-brand-faculty {
            font-size: 11px;
            color: var(--ink-50);
            font-weight: 600;
            margin-top: 2px;
        }

        .header-back {
            display: flex;
            align-items: center;
            gap: 6px;
            font-size: 12px;
            font-weight: 700;
            color: var(--ink-50);
            text-decoration: none;
            padding: 6px 12px;
            border: 1px solid var(--ink-15);
            border-radius: var(--r-sm);
            transition: var(--transition);
        }

        .header-back:hover {
            color: var(--ink);
            border-color: var(--ink-70);
            background: var(--ink-07);
            transform: translateY(-1px);
        }

        .header-back i {
            font-size: 9px;
        }

        /* Layout */
        .page-layout {
            max-width: 1200px;
            margin: 0 auto;
            padding: 40px 32px 80px;
            display: grid;
            grid-template-columns: 1fr 1.1fr;
            gap: 40px;
            align-items: start;
        }

        .info-panel {
            position: sticky;
            top: 110px;
        }

        .info-eyebrow {
            display: inline-flex;
            align-items: center;
            gap: 8px;
            font-size: 11px;
            font-weight: 800;
            letter-spacing: .12em;
            text-transform: uppercase;
            color: var(--ink-50);
            margin-bottom: 12px;
        }

        .info-eyebrow::before {
            content: '';
            width: 16px;
            height: 2px;
            background: var(--ink);
            border-radius: 2px;
        }

        .info-heading {
            font-size: clamp(28px, 3.2vw, 38px);
            font-weight: 800;
            line-height: 1.25;
            color: var(--ink);
            letter-spacing: -.02em;
            margin-bottom: 16px;
        }

        .info-desc {
            font-size: 14.5px;
            line-height: 1.8;
            color: var(--ink-50);
            margin-bottom: 32px;
            max-width: 440px;
        }

        /* Cards and Elements */
        .form-card {
            background: var(--white);
            border: 1px solid rgba(13, 17, 23, 0.06);
            border-radius: var(--r-lg);
            overflow: hidden;
            margin-bottom: 20px;
            box-shadow: var(--card-shadow);
            transition: var(--transition);
        }

        .form-card:hover {
            box-shadow: var(--card-shadow-hover);
            border-color: rgba(13, 17, 23, 0.12);
        }

        .card-bar {
            background: var(--ink);
            padding: 20px 24px;
            display: flex;
            align-items: center;
            justify-content: space-between;
            border-bottom: 1px solid rgba(13, 17, 23, 0.05);
        }

        .card-bar-left {
            display: flex;
            align-items: center;
            gap: 12px;
        }

        .card-bar-icon {
            width: 36px;
            height: 36px;
            background: rgba(255, 255, 255, 0.1);
            border: 1px solid rgba(255, 255, 255, 0.15);
            border-radius: var(--r-sm);
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 15px;
            color: var(--white);
        }

        .card-bar-text {
            line-height: 1.2;
        }

        .card-bar-label {
            font-size: 9.5px;
            font-weight: 700;
            letter-spacing: .12em;
            text-transform: uppercase;
            color: rgba(255, 255, 255, .4);
        }

        .card-bar-title {
            font-size: 14.5px;
            font-weight: 800;
            color: var(--white);
            margin-top: 2px;
        }

        .card-body {
            padding: 24px;
        }

        /* Topic Item Container */
        .topic-item {
            margin-bottom: 24px;
            background: var(--ink-07);
            border: 1px solid var(--ink-15);
            padding: 20px;
            border-radius: var(--r-md);
            transition: var(--transition);
        }

        .topic-item:hover {
            background: var(--white);
            border-color: var(--ink-30);
            box-shadow: var(--card-shadow);
        }

        .topic-title {
            font-weight: 800;
            margin-bottom: 12px;
            display: flex;
            align-items: center;
            gap: 8px;
            color: var(--ink);
            font-size: 15px;
        }

        .topic-title i {
            font-size: 16px;
        }

        .topic-content {
            font-size: 13.5px;
            color: var(--ink-70);
            line-height: 1.75;
            font-weight: 500;
        }

        .topic-content ul {
            padding-left: 18px;
            margin-top: 8px;
        }

        .topic-content li {
            margin-bottom: 6px;
        }

        .topic-content li b {
            color: var(--ink);
            font-weight: 700;
        }

        /* Diagrams style */
        .diagram-img {
            width: 100%;
            border-radius: var(--r-xs);
            margin-top: 8px;
            cursor: pointer;
            border: 1px solid var(--ink-15);
            transition: var(--transition);
        }

        .diagram-img:hover {
            transform: scale(1.015);
            border-color: var(--ink-70);
            box-shadow: var(--card-shadow);
        }

        /* Buttons */
        .btn {
            width: 100%;
            border-radius: var(--r-sm);
            padding: 14px 20px;
            font-family: inherit;
            font-size: 14.5px;
            font-weight: 700;
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 8px;
            text-decoration: none;
            transition: var(--transition);
            border: none;
        }

        .btn-primary {
            background: var(--ink);
            color: var(--white);
            box-shadow: 0 4px 12px rgba(13, 17, 23, 0.15);
        }

        .btn-primary:hover {
            background: var(--ink-70);
            transform: translateY(-2px);
        }

        /* Lightbox Image Viewer Overlay */
        .image-viewer-overlay {
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: rgba(13, 17, 23, 0.6);
            backdrop-filter: blur(12px);
            -webkit-backdrop-filter: blur(12px);
            z-index: 3000;
            display: flex;
            align-items: center;
            justify-content: center;
            opacity: 0;
            visibility: hidden;
            transition: var(--transition);
            padding: 24px;
        }

        .image-viewer-overlay.active {
            opacity: 1;
            visibility: visible;
        }

        .image-viewer-content {
            max-width: 100%;
            max-height: 90vh;
            border-radius: var(--r-md);
            box-shadow: 0 30px 60px -15px rgba(13, 17, 23, 0.3);
            border: 1px solid rgba(255, 255, 255, 0.1);
            transform: scale(0.95);
            transition: var(--transition-bounce);
        }

        .image-viewer-overlay.active .image-viewer-content {
            transform: scale(1);
        }

        .image-viewer-close {
            position: absolute;
            top: 24px;
            right: 24px;
            color: var(--white);
            font-size: 18px;
            cursor: pointer;
            z-index: 3001;
            background: rgba(13, 17, 23, 0.5);
            width: 44px;
            height: 44px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            border: 1px solid rgba(255, 255, 255, 0.2);
            transition: var(--transition);
        }

        .image-viewer-close:hover {
            background: var(--ink);
            transform: rotate(90deg);
        }

        footer {
            text-align: center;
            margin-top: 40px;
            font-size: 12px;
            color: var(--ink-30);
            line-height: 1.6;
        }

        /* Responsive styling */
        @media (max-width: 900px) {
            .page-layout {
                grid-template-columns: 1fr;
                padding: 32px 20px 64px;
                gap: 32px;
            }

            .info-panel {
                position: static;
            }

            .header-inner {
                padding: 0 20px;
            }
        }

        @media (max-width: 540px) {
            .page-layout {
                padding: 24px 16px 60px;
            }

            .header-brand-faculty {
                display: none;
            }
        }