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

        body {
            font-family: 'Inter', sans-serif;
            background: #f4f9fe;
            color: #1a2c3e;
            line-height: 1.5;
        }

        /* main header (brand) */
        .main-header {
            background: white;
            padding: 1rem 2rem;
            border-bottom: 1px solid #e2e8f0;
            box-shadow: 0 2px 8px rgba(0,0,0,0.02);
        }
        .header-container {
            max-width: 1280px;
            margin: 0 auto;
            display: flex;
            justify-content: space-between;
            align-items: center;
            flex-wrap: wrap;
            gap: 1rem;
        }
        .header-logo {
            font-size: 1.9rem;
            font-weight: 800;
            background: linear-gradient(135deg, #0f2b3d, #1b4d6e);
            -webkit-background-clip: text;
            background-clip: text;
            color: transparent;
        }
        .header-logo span {
            background: none;
            color: #2c7a4d;
            font-weight: 700;
        }
        .header-tagline {
            font-size: 0.8rem;
            color: #4a627a;
            margin-top: 4px;
        }
        .nav-links a {
            text-decoration: none;
            margin-left: 1.8rem;
            font-weight: 500;
            color: #2c3e50;
            transition: 0.2s;
        }
        .nav-links a:hover {
            color: #2c7a4d;
        }

        /* hero / sticky section */
        .sticky-hero-section {
            background: linear-gradient(105deg, #eef2f5 0%, #ffffff 80%);
            padding: 2rem 2rem 1.5rem;
            border-bottom: 1px solid #dce5ec;
        }
        .hero-box {
            max-width: 1280px;
            margin: 0 auto;
        }
        .hero-title {
            font-size: 2.2rem;
            font-weight: 700;
            color: #0a2f44;
        }
        .hero-sub {
            font-size: 1rem;
            color: #2c5a74;
            margin-top: 0.5rem;
        }

        /* live session banner */
        .live-banner {
            background: #ffeed9;
            border-left: 6px solid #e67e22;
            padding: 1rem 2rem;
            margin: 1.5rem 2rem;
            border-radius: 20px;
            display: flex;
            justify-content: space-between;
            align-items: center;
            flex-wrap: wrap;
            gap: 1rem;
        }
        .live-banner h3 i {
            color: #e67e22;
        }
        .join-btn {
            background: #e67e22;
            border: none;
            padding: 0.6rem 1.5rem;
            border-radius: 40px;
            font-weight: 600;
            color: white;
            cursor: pointer;
            transition: 0.2s;
        }
        .join-btn:hover {
            background: #bf5e0a;
            transform: scale(0.98);
        }

        /* two-column layout: forums + quizzes */
        .dashboard {
            max-width: 1280px;
            margin: 0 auto;
            padding: 0 2rem 2rem;
            display: flex;
            flex-wrap: wrap;
            gap: 2rem;
        }
        .forum-section {
            flex: 2;
            min-width: 260px;
            background: white;
            border-radius: 28px;
            box-shadow: 0 8px 20px rgba(0,0,0,0.03);
            padding: 1.5rem;
            border: 1px solid #e9edf2;
        }
        .quiz-section {
            flex: 1.5;
            min-width: 280px;
            background: white;
            border-radius: 28px;
            padding: 1.5rem;
            border: 1px solid #e9edf2;
            box-shadow: 0 8px 20px rgba(0,0,0,0.03);
        }
        .section-header {
            font-size: 1.6rem;
            font-weight: 700;
            margin-bottom: 1.2rem;
            display: flex;
            align-items: center;
            gap: 0.6rem;
            border-left: 5px solid #2c7a4d;
            padding-left: 0.8rem;
        }
        .forum-topic {
            background: #fafcff;
            border-radius: 20px;
            padding: 1rem;
            margin-bottom: 1rem;
            border: 1px solid #eef2f8;
            transition: 0.1s;
        }
        .topic-title {
            font-weight: 700;
            font-size: 1.1rem;
            display: flex;
            justify-content: space-between;
        }
        .topic-meta {
            font-size: 0.75rem;
            color: #6c86a3;
            margin: 6px 0 8px;
            display: flex;
            gap: 12px;
        }
        .reply-btn, .new-post-btn {
            background: none;
            border: 1px solid #cbdde9;
            padding: 0.3rem 0.8rem;
            border-radius: 30px;
            font-size: 0.7rem;
            cursor: pointer;
            transition: 0.1s;
        }
        .reply-btn:hover, .new-post-btn:hover {
            background: #eef3fc;
        }
        .new-discussion {
            margin-top: 1.2rem;
            display: flex;
            gap: 0.6rem;
        }
        .new-discussion input {
            flex: 1;
            padding: 0.7rem;
            border-radius: 40px;
            border: 1px solid #ccdbe8;
            font-family: inherit;
        }
        .post-btn {
            background: #2c7a4d;
            color: white;
            border: none;
            border-radius: 40px;
            padding: 0 1.2rem;
            font-weight: 500;
            cursor: pointer;
        }

        /* role quiz switcher & cards */
        .role-selector {
            display: flex;
            gap: 1rem;
            margin-bottom: 1.8rem;
            background: #f0f4f9;
            padding: 0.4rem;
            border-radius: 60px;
        }
        .role-btn {
            flex: 1;
            text-align: center;
            padding: 0.5rem;
            border-radius: 40px;
            background: transparent;
            border: none;
            font-weight: 600;
            cursor: pointer;
            transition: 0.2s;
        }
        .role-btn.active {
            background: #2c7a4d;
            color: white;
            box-shadow: 0 2px 6px rgba(0,0,0,0.1);
        }
        .quiz-card {
            background: #fefef7;
            border-radius: 24px;
            padding: 1.2rem;
            margin-top: 0.5rem;
            border: 1px solid #eaeef4;
        }
        .quiz-question {
            font-weight: 600;
            margin: 0.8rem 0 0.6rem;
        }
        .quiz-option {
            display: block;
            margin: 0.5rem 0;
            padding-left: 1.8rem;
            position: relative;
        }
        .quiz-option input {
            margin-right: 0.6rem;
        }
        .submit-quiz {
            background: #1f6392;
            color: white;
            border: none;
            padding: 0.5rem 1.2rem;
            border-radius: 30px;
            font-weight: 500;
            margin-top: 1rem;
            cursor: pointer;
        }
        .quiz-feedback {
            margin-top: 1rem;
            font-size: 0.85rem;
            background: #eef3fa;
            padding: 0.6rem;
            border-radius: 16px;
        }

        /* live session modal */
        .modal {
            display: none;
            position: fixed;
            top: 0; left: 0;
            width: 100%; height: 100%;
            background: rgba(0,0,0,0.5);
            align-items: center;
            justify-content: center;
            z-index: 1000;
        }
        .modal-content {
            background: white;
            max-width: 500px;
            width: 90%;
            border-radius: 32px;
            padding: 1.8rem;
            text-align: center;
        }
        .close-modal {
            float: right;
            font-size: 1.5rem;
            cursor: pointer;
        }
        .session-video {
            width: 100%;
            height: 200px;
            background: #0f2b3d;
            border-radius: 20px;
            display: flex;
            align-items: center;
            justify-content: center;
            color: white;
            margin: 1rem 0;
        }

        footer {
            background: #0a2a3b;
            color: #cfdfed;
            margin-top: 3rem;
            padding: 2rem 2rem 1rem;
        }
        .footer-grid {
            max-width: 1280px;
            margin: 0 auto;
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(180px,1fr));
            gap: 2rem;
        }
        .footer-col h3 {
            font-size: 1rem;
            margin-bottom: 0.8rem;
            color: white;
        }
        .footer-col ul {
            list-style: none;
        }
        .footer-col li, .footer-col a {
            color: #bdd4e2;
            text-decoration: none;
            font-size: 0.8rem;
            line-height: 1.8;
        }
        .copyright {
            text-align: center;
            padding-top: 2rem;
            font-size: 0.7rem;
        }
        @media (max-width: 780px) {
            .dashboard {
                flex-direction: column;
            }
            .live-banner {
                margin: 1rem;
            }
        }
        .badge-icon {
            background: #eef2fa;
            border-radius: 30px;
            padding: 0.2rem 0.6rem;
            font-size: 0.7rem;
        }