* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
        }

        body {
            background: linear-gradient(145deg, #f8fafc 0%, #eef2f7 100%);
            color: #1e293b;
            scroll-behavior: smooth;
        }

        /* ========= GLOBAL CONTAINER ========= */
        .container {
            max-width: 1280px;
            margin: 0 auto;
            padding: 0 24px;
        }

        /* ========= TOP NOTICE BAR + LOGIN/REGISTER + WHATSAPP ROW ========= */
        .top-action-bar {
            background: #0f172a;
            color: #f1f5f9;
            padding: 12px 0;
            border-bottom: 3px solid #f97316;
            position: relative;
            z-index: 10;
        }

        .top-flex {
            display: flex;
            flex-wrap: wrap;
            align-items: center;
            justify-content: space-between;
            gap: 15px;
        }

        /* marquee notice */
        .notice-marquee {
            flex: 2;
            min-width: 240px;
            background: rgba(255,255,240,0.08);
            padding: 6px 16px;
            border-radius: 40px;
            backdrop-filter: blur(2px);
            overflow: hidden;
            white-space: nowrap;
        }

        .notice-marquee marquee {
            font-size: 1.05rem;
            font-weight: 500;
            letter-spacing: 0.3px;
            color: #ffedd5;
        }

        .notice-marquee marquee i {
            margin-right: 12px;
            color: #f97316;
        }

        /* student + whatsapp section */
        .auth-wa-group {
            display: flex;
            flex-wrap: wrap;
            align-items: center;
            gap: 20px;
            background: transparent;
        }

        .auth-buttons {
            display: flex;
            gap: 12px;
        }

        .btn-login, .btn-register {
            padding: 6px 20px;
            border-radius: 40px;
            font-weight: 600;
            font-size: 1.85rem;
            text-decoration: none;
            transition: 0.2s;
            display: inline-block;
            text-align: center;
            background: transparent;
            border: 1px solid #facc15;
            color: #facc15;
        }

        .btn-register {
            background: #f97316;
            border: none;
            color: white;
            box-shadow: 0 2px 6px rgba(249,115,22,0.3);
        }

        .btn-login:hover {
            background: #facc15;
            color: #0f172a;
        }
        .btn-register:hover {
            background: #ea580c;
            transform: scale(1.02);
        }

        .wa-contact {
            display: flex;
            gap: 10px;
            background: #075e54;
            padding: 5px 14px;
            border-radius: 50px;
            align-items: center;
        }
        .wa-contact a {
            color: white;
            text-decoration: none;
            font-size: 1.05rem;
            font-weight: 500;
            display: inline-flex;
            align-items: center;
            gap: 6px;
        }
        .wa-contact i {
            font-size: 1.1rem;
        }

        /* ========= SOCIAL VERTICAL SECTION (RIGHT SIDEBAR STYLE) ========= */
        .social-vertical-section {
            position: fixed;
            right: 20px;
            top: 50%;
            transform: translateY(-50%);
            background: rgba(255,255,255,0.94);
            backdrop-filter: blur(8px);
            border-radius: 48px;
            padding: 16px 8px;
            display: flex;
            flex-direction: column;
            gap: 18px;
            box-shadow: 0 12px 28px rgba(0,0,0,0.2);
            z-index: 999;
            border: 1px solid rgba(249,115,22,0.4);
        }
        .social-vertical-section a {
            display: block;
            text-align: center;
            transition: 0.2s;
            font-size: 1.8rem;
            color: #334155;
        }
        .social-vertical-section a:hover {
            transform: scale(1.18);
            color: #f97316;
        }
        /* custom icons (emoji fallback or fontawesome style) */
        .social-icon {
            width: 44px;
            height: 44px;
            display: flex;
            align-items: center;
            justify-content: center;
            background: #f1f5f9;
            border-radius: 50%;
            transition: 0.2s;
        }
        .social-vertical-section a:hover .social-icon {
            background: #f97316;
            color: white;
        }

        /* ========= HERO WELCOME SECTION ========= */
        .hero {
            text-align: center;
            margin: 40px 0 30px;
        }
        .hero h1 {
            font-size: 2.5rem;
            background: linear-gradient(135deg, #0f172a, #b45309);
            -webkit-background-clip: text;
            background-clip: text;
            color: transparent;
            margin-bottom: 8px;
        }
        .hero p {
            color: #334155;
            font-size: 1.1rem;
        }

        /* ========= THREE CIRCLE COURSES SECTION ========= */
        .courses-circle-section {
            margin: 70px 0 60px;
        }
        .section-title {
            text-align: center;
            font-size: 2.0rem;
            font-weight: 700;
            margin: 2.2rem 0 8.2rem;
            margin-bottom: 45px;
            position: relative;
            display: inline-block;
            width: 100%;
        }
        .section-title:after {
            content: '';
            width: 80px;
            height: 4px;
            background: #f97316;
            display: block;
            margin: 10px auto 0;
            border-radius: 4px;
        }
        .circle-grid {
            display: flex;
            flex-wrap: wrap;
            justify-content: center;
            gap: 50px;
        }
        .course-card {
            background: white;
            border-radius: 50%;
            width: 280px;
            height: 280px;
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            text-align: center;
            box-shadow: 0 20px 35px -12px rgba(0,0,0,0.2);
            transition: all 0.3s ease;
            border: 5px solid #ffedd5;
            cursor: default;
            padding: 20px;
        }
        .course-card:hover {
            transform: translateY(-10px) scale(1.02);
            border-color: #f97316;
            box-shadow: 0 28px 40px -14px rgba(249,115,22,0.3);
        }
        .circle-icon {
            font-size: 4.2rem;
            margin-bottom: 12px;
        }
        .course-card h3 {
            font-size: 1.45rem;
            color: #0f172a;
            margin-bottom: 12px;
        }
        .course-badge {
            background: #fef3c7;
            padding: 4px 12px;
            border-radius: 40px;
            font-size: 0.7rem;
            font-weight: bold;
            color: #b45309;
            margin: 5px 0;
        }
        .course-desc {
            font-size: 1.8rem;
            color: #475569;
            margin: 8px 12px;
            line-height: 1.3;
        }
        .feature-list {
            font-size: 0.85rem;
            list-style: none;
            margin-top: 6px;
        }
        .feature-list li {
            display: inline-block;
            background: #eef2ff;
            margin: 3px 4px;
            padding: 2px 8px;
            border-radius: 20px;
        }
        .btn-circle-action {
            margin-top: 12px;
            background: #f97316;
            border: none;
            color: white;
            padding: 5px 14px;
            border-radius: 30px;
            font-size: 1.9rem;
            font-weight: bold;
            text-decoration: none;
            display: inline-block;
        }

        /* responsive circles */
        @media (max-width: 880px) {
            .course-card {
                width: 240px;
                height: 240px;
            }
            .circle-icon {
                font-size: 3rem;
            }
            .social-vertical-section {
                right: 8px;
                padding: 12px 4px;
                gap: 12px;
            }
            .social-icon {
                width: 36px;
                height: 36px;
                font-size: 1.3rem;
            }
        }
        @media (max-width: 700px) {
            .circle-grid {
                gap: 30px;
            }
            .top-flex {
                flex-direction: column;
                align-items: stretch;
            }
            .notice-marquee {
                white-space: normal;
            }
            .auth-wa-group {
                justify-content: space-between;
            }
        }

        /* ========= ADDITIONAL INFO SECTION (BRIEF) ========= */
        .stats-banner {
            background: #0f172a;
            color: white;
            border-radius: 32px;
            padding: 28px 20px;
            margin: 40px 0;
            display: flex;
            flex-wrap: wrap;
            justify-content: space-around;
            text-align: center;
        }
        .stat-item h3 {
            font-size: 1.8rem;
            color: #facc15;
        }

        footer {
            text-align: center;
            padding: 30px 0 20px;
            border-top: 1px solid #cbd5e1;
            margin-top: 30px;
            font-size: 0.8rem;
            color: #475569;
        }
        a {
            text-decoration: none;
        }