:root {
            --bg-color: #0c1222;
            --panel-bg: #111827;
            --border-color: #1f2937;
            --border-hover: #374151;
            --primary: #6366f1;
            --secondary: #0ea5e9;
            --accent: #a855f7;
            --text-main: #f9fafb;
            --text-muted: #9ca3af;
        }

        * {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
            font-family: 'Outfit', 'Noto Sans TC', sans-serif;
            scroll-behavior: smooth;
        }

        body {
            background-color: var(--bg-color);
            color: var(--text-main);
            min-height: 100vh;
            overflow-x: hidden;
            display: flex;
            flex-direction: column;
            position: relative;
        }

        /* Brand Navigation Bar */
        nav {
            padding: 1rem 2rem;
            border-bottom: 1px solid var(--border-color);
            background: #0c1222;
            display: flex;
            align-items: center;
            justify-content: space-between;
            z-index: 10;
            position: sticky;
            top: 0;
            width: 100%;
        }

        .nav-container {
            max-width: 1280px;
            margin: 0 auto;
            width: 100%;
            display: flex;
            align-items: center;
            justify-content: space-between;
        }

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

        .logo-img {
            height: 36px;
            width: auto;
            transition: transform 0.2s ease;
        }

        .brand-logo:hover .logo-img {
            transform: scale(1.02);
        }

        .brand-name {
            font-size: 1.15rem;
            font-weight: 700;
            color: #ffffff;
            transition: color 0.2s;
        }

        .brand-logo:hover .brand-name {
            color: #818cf8;
        }

        .nav-links {
            display: flex;
            gap: 1.5rem;
        }

        .nav-link {
            color: var(--text-muted);
            text-decoration: none;
            font-size: 0.85rem;
            font-weight: 600;
            padding: 0.5rem 0.8rem;
            border-radius: 8px;
            transition: all 0.2s;
        }

        .nav-link:hover {
            color: #ffffff;
            background: rgba(255, 255, 255, 0.03);
        }

        /* Banner Header */
        header {
            padding: 4rem 2rem 2.5rem;
            text-align: center;
            max-width: 800px;
            margin: 0 auto;
            position: relative;
            z-index: 1;
        }

        .badge-top {
            display: inline-flex;
            align-items: center;
            padding: 0.5rem 1.2rem;
            background: rgba(255, 255, 255, 0.02);
            border: 1px solid var(--border-color);
            border-radius: 30px;
            margin-bottom: 1.5rem;
        }

        .badge-top span {
            color: #a5b4fc;
            font-weight: 600;
            font-size: 0.75rem;
            letter-spacing: 1px;
            text-transform: uppercase;
        }

        header h1 {
            font-size: 3.5rem;
            font-weight: 800;
            letter-spacing: -1px;
            margin-bottom: 1.2rem;
            line-height: 1.15;
            color: #ffffff;
        }

        @media (max-width: 768px) {
            header h1 {
                font-size: 2.5rem;
            }
        }

        header h1 span.gradient-text {
            background: linear-gradient(135deg, #6366f1 30%, #a855f7 90%);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
        }

        header p {
            color: var(--text-muted);
            font-size: 1.05rem;
            font-weight: 400;
            line-height: 1.6;
            max-width: 600px;
            margin: 0 auto;
        }

        /* Link Generator Widget styling */
        .link-generator-panel {
            background: var(--panel-bg);
            border: 1px solid var(--border-color);
            border-radius: 20px;
            padding: 1.5rem 2rem;
            max-width: 1350px;
            width: calc(100% - 4rem);
            margin: 0 auto 2rem;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
            display: flex;
            flex-direction: column;
            gap: 1rem;
            position: relative;
            z-index: 1;
        }

        .generator-header {
            display: flex;
            align-items: center;
            gap: 10px;
            border-bottom: 1px solid rgba(255, 255, 255, 0.05);
            padding-bottom: 0.6rem;
        }

        .generator-header h3 {
            font-size: 0.95rem;
            font-weight: 700;
            color: #ffffff;
            letter-spacing: 0.5px;
        }

        .generator-body {
            display: grid;
            grid-template-columns: 1.2fr 1.2fr 2fr;
            gap: 1.5rem;
            align-items: flex-end;
        }

        @media (max-width: 768px) {
            .generator-body {
                grid-template-columns: 1fr;
                gap: 1rem;
            }
            .link-generator-panel {
                width: calc(100% - 3rem);
                padding: 1.2rem 1.5rem;
            }
        }

        .select-group {
            display: flex;
            flex-direction: column;
            gap: 0.5rem;
        }

        .select-group label {
            font-size: 0.8rem;
            font-weight: 600;
            color: var(--text-muted);
        }

        .select-group select {
            background: rgba(255, 255, 255, 0.03);
            border: 1px solid var(--border-color);
            color: #ffffff;
            padding: 0.7rem;
            border-radius: 12px;
            outline: none;
            cursor: pointer;
            transition: border-color 0.2s;
            font-size: 0.85rem;
        }

        .select-group select:hover:not(:disabled) {
            border-color: var(--border-hover);
        }

        .select-group select:focus {
            border-color: var(--primary);
        }

        .result-group {
            display: flex;
            gap: 0.8rem;
        }

        .result-group input {
            flex-grow: 1;
            background: rgba(0, 0, 0, 0.2);
            border: 1px solid var(--border-color);
            color: var(--text-muted);
            padding: 0.7rem;
            border-radius: 12px;
            font-size: 0.85rem;
            outline: none;
        }

        .result-group button {
            background: var(--primary);
            color: #ffffff;
            border: none;
            padding: 0.7rem 1.5rem;
            border-radius: 12px;
            font-weight: 600;
            cursor: pointer;
            transition: opacity 0.2s;
            font-size: 0.85rem;
            white-space: nowrap;
        }

        .result-group button:hover {
            opacity: 0.9;
        }

        /* Grid Columns Workspace */
        .container {
            max-width: 1350px;
            margin: 0 auto;
            padding: 0 2rem 5rem;
            width: 100%;
            flex-grow: 1;
            display: grid;
            grid-template-columns: 1fr 1.2fr 1.8fr;
            gap: 2rem;
            position: relative;
            z-index: 1;
        }

        @media (max-width: 1024px) {
            .container {
                grid-template-columns: 1fr !important;
                gap: 1.5rem;
                padding: 0 1.5rem 3rem;
            }
        }

        /* Modern Dark Panels */
        .panel {
            background: var(--panel-bg);
            border: 1px solid var(--border-color);
            border-radius: 24px;
            padding: 2rem;
            display: flex;
            flex-direction: column;
            box-shadow: 0 15px 35px rgba(0, 0, 0, 0.25);
            transition: all 0.2s ease;
            height: 620px;
            overflow: hidden; /* Prevent parent scrolling */
        }

        @media (max-width: 1024px) {
            .panel {
                height: 420px;
            }
        }

        .panel-header {
            display: flex;
            align-items: center;
            margin-bottom: 1.8rem;
            padding-bottom: 1rem;
            border-bottom: 1px solid rgba(255, 255, 255, 0.04);
        }

        .panel-header .badge {
            width: 6px;
            height: 6px;
            border-radius: 50%;
            margin-right: 12px;
            background-color: var(--primary);
        }

        .panel-header h2 {
            font-size: 1rem;
            font-weight: 700;
            letter-spacing: 0.5px;
            text-transform: uppercase;
            color: #ffffff;
        }

        /* Card list */
        .list {
            display: flex;
            flex-direction: column;
            gap: 0.8rem;
            overflow-y: auto;
            flex-grow: 1;
            padding-right: 6px;
        }

        /* Customize Scrollbars */
        .list::-webkit-scrollbar {
            width: 5px;
        }
        .list::-webkit-scrollbar-track {
            background: transparent;
        }
        .list::-webkit-scrollbar-thumb {
            background: #1f2937;
            border-radius: 10px;
        }
        .list::-webkit-scrollbar-thumb:hover {
            background: #374151;
        }

        /* Clean Card Selector */
        .item-card {
            background: rgba(255, 255, 255, 0.01);
            border: 1px solid rgba(255, 255, 255, 0.02);
            border-left: 3px solid transparent;
            border-radius: 14px;
            padding: 1rem 1.2rem;
            cursor: pointer;
            transition: all 0.2s;
            display: flex;
            align-items: center;
            justify-content: space-between;
            position: relative;
        }

        .item-card:hover {
            background: rgba(255, 255, 255, 0.03);
            border-color: var(--border-hover);
        }

        #panel-classes .item-card:hover, #panel-classes .item-card.active {
            border-left-color: var(--primary);
        }
        #panel-classes .item-card.active {
            background: rgba(99, 102, 241, 0.05);
            border-color: rgba(99, 102, 241, 0.15);
        }

        #panel-students .item-card:hover, #panel-students .item-card.active {
            border-left-color: var(--accent);
        }
        #panel-students .item-card.active {
            background: rgba(168, 85, 247, 0.05);
            border-color: rgba(168, 85, 247, 0.15);
        }

        /* Project Cards */
        .project-card {
            background: rgba(255, 255, 255, 0.01);
            border: 1px solid rgba(255, 255, 255, 0.02);
            border-left: 3px solid transparent;
            border-radius: 16px;
            padding: 1.3rem;
            cursor: pointer;
            transition: all 0.2s;
            display: flex;
            flex-direction: column;
            gap: 1rem;
            position: relative;
        }

        .project-card:hover {
            background: rgba(255, 255, 255, 0.03);
            border-color: var(--border-hover);
        }

        .project-card.hover-python:hover {
            border-left-color: var(--primary);
            border-color: rgba(99, 102, 241, 0.15);
        }

        .project-card.hover-scratch:hover {
            border-left-color: #f97316;
            border-color: rgba(249, 115, 22, 0.15);
        }

        .project-card.hover-makecode:hover {
            border-left-color: #0ea5e9;
            border-color: rgba(14, 165, 233, 0.15);
        }

        .project-card.hover-html:hover {
            border-left-color: #10b981;
            border-color: rgba(16, 185, 129, 0.15);
        }

        .project-card.hover-apk:hover {
            border-left-color: #a855f7;
            border-color: rgba(168, 85, 247, 0.15);
        }

        .project-meta {
            display: flex;
            align-items: center;
            justify-content: space-between;
            gap: 1rem;
        }

        .project-title {
            font-size: 1.05rem;
            font-weight: 600;
            color: #ffffff;
            letter-spacing: 0.2px;
        }

        /* Type Badges */
        .project-tag {
            font-size: 0.68rem;
            padding: 0.25rem 0.65rem;
            border-radius: 30px;
            font-weight: 600;
            letter-spacing: 0.5px;
            text-transform: uppercase;
        }

        .tag-python {
            background: rgba(99, 102, 241, 0.08);
            color: #a5b4fc;
            border: 1px solid rgba(99, 102, 241, 0.15);
        }

        .tag-scratch {
            background: rgba(249, 115, 22, 0.08);
            color: #fed7aa;
            border: 1px solid rgba(249, 115, 22, 0.15);
        }

        .tag-makecode {
            background: rgba(14, 165, 233, 0.08);
            color: #bae6fd;
            border: 1px solid rgba(14, 165, 233, 0.15);
        }

        .tag-html {
            background: rgba(16, 185, 129, 0.08);
            color: #a7f3d0;
            border: 1px solid rgba(16, 185, 129, 0.15);
        }

        .tag-apk {
            background: rgba(168, 85, 247, 0.08);
            color: #d8b4fe;
            border: 1px solid rgba(168, 85, 247, 0.15);
        }

        /* Action launch button */
        .btn-launch {
            border: none;
            color: #ffffff;
            font-weight: 600;
            padding: 0.75rem 1.2rem;
            border-radius: 12px;
            font-size: 0.85rem;
            cursor: pointer;
            transition: all 0.2s;
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 8px;
            width: 100%;
        }

        .btn-launch:active {
            transform: scale(0.99);
        }

        .btn-launch-python {
            background: var(--primary);
        }
        .btn-launch-python:hover {
            background: #4f46e5;
        }

        .btn-launch-scratch {
            background: #ea580c;
        }
        .btn-launch-scratch:hover {
            background: #d97706;
        }

        .btn-launch-makecode {
            background: #0284c7;
        }
        .btn-launch-makecode:hover {
            background: #0369a1;
        }

        .btn-launch-html {
            background: #059669;
        }
        .btn-launch-html:hover {
            background: #047857;
        }

        .btn-launch-apk {
            background: var(--accent);
        }
        .btn-launch-apk:hover {
            background: #9333ea;
        }

        /* Placeholder */
        .empty-placeholder {
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            text-align: center;
            color: var(--text-muted);
            padding: 4rem 1rem;
            height: 100%;
            gap: 1rem;
            font-weight: 400;
        }

        .empty-placeholder svg {
            width: 32px;
            height: 32px;
            stroke: currentColor;
            opacity: 0.3;
        }

        .empty-placeholder p {
            font-size: 0.85rem;
            line-height: 1.6;
        }

        /* Footer */
        footer {
            text-align: center;
            padding: 1.8rem;
            color: var(--text-muted);
            font-size: 0.8rem;
            border-top: 1px solid var(--border-color);
            background: #0c1222;
            position: relative;
            z-index: 1;
            margin-top: auto;
        }