/* ===========================================
           STEP 1: DEFINE DESIGN SYSTEM VARIABLES
           =========================================== */
        :root {
            /* === COLOR SYSTEM === */
            --color-primary: #2c5aa0;      /* Biru utama - professional */
            --color-primary-light: #4a90e2; /* Biru muda */
            --color-primary-dark: #1e3a6f;  /* Biru tua */
            
            --color-secondary: #ffcc00;     /* Kuning aksen */
            --color-success: #28a745;       /* Hijau sukses */
            --color-danger: #dc3545;        /* Merah danger */
            --color-warning: #ffc107;       /* Kuning warning */
            --color-info: #17a2b8;          /* Biru info */
            
            --color-text: #333333;          /* Warna teks utama */
            --color-text-light: #666666;    /* Teks sekunder */
            --color-text-muted: #999999;    /* Teks tersier */
            
            --color-bg: #f9f9f9;            /* Background utama */
            --color-bg-light: #ffffff;      /* Background card */
            --color-bg-dark: #222222;       /* Background footer */
            
            --color-border: #e0e0e0;        /* Warna border */
            --color-shadow: rgba(0, 0, 0, 0.1); /* Warna shadow */
            
            /* === TYPOGRAPHY SYSTEM === */
            --font-heading: 'Poppins', sans-serif;
            --font-body: 'Open Sans', sans-serif;
            
            --font-size-xs: 0.75rem;    /* 12px */
            --font-size-sm: 0.875rem;   /* 14px */
            --font-size-base: 1rem;     /* 16px */
            --font-size-md: 1.125rem;   /* 18px */
            --font-size-lg: 1.25rem;    /* 20px */
            --font-size-xl: 1.5rem;     /* 24px */
            --font-size-2xl: 2rem;      /* 32px */
            --font-size-3xl: 2.5rem;    /* 40px */
            
            --font-weight-light: 300;
            --font-weight-normal: 400;
            --font-weight-medium: 500;
            --font-weight-semibold: 600;
            --font-weight-bold: 700;
            
            --line-height-tight: 1.25;
            --line-height-normal: 1.6;
            --line-height-loose: 1.8;
            
            /* === SPACING SYSTEM (8px grid) === */
            --space-1: 0.25rem;   /* 4px */
            --space-2: 0.5rem;    /* 8px */
            --space-3: 0.75rem;   /* 12px */
            --space-4: 1rem;      /* 16px */
            --space-5: 1.25rem;   /* 20px */
            --space-6: 1.5rem;    /* 24px */
            --space-8: 2rem;      /* 32px */
            --space-10: 2.5rem;   /* 40px */
            --space-12: 3rem;     /* 48px */
            --space-16: 4rem;     /* 64px */
            --space-20: 5rem;     /* 80px */
            
            /* === BORDER SYSTEM === */
            --border-radius-sm: 0.25rem;  /* 4px */
            --border-radius: 0.5rem;      /* 8px */
            --border-radius-lg: 1rem;     /* 16px */
            --border-radius-xl: 1.5rem;   /* 24px */
            --border-radius-full: 9999px; /* pill */
            
            --border-width: 1px;
            --border-width-thick: 2px;
            
            /* === SHADOW SYSTEM === */
            --shadow-sm: 0 1px 3px var(--color-shadow);
            --shadow: 0 4px 6px var(--color-shadow);
            --shadow-md: 0 5px 15px var(--color-shadow);
            --shadow-lg: 0 10px 25px var(--color-shadow);
            --shadow-xl: 0 20px 40px var(--color-shadow);
            
            /* === LAYOUT SYSTEM === */
            --container-max-width: 1200px;
            --header-height: 80px;
            --section-spacing: var(--space-20);
            
            /* === TRANSITION SYSTEM === */
            --transition-fast: 150ms;
            --transition-normal: 300ms;
            --transition-slow: 500ms;
            --transition-bounce: cubic-bezier(0.68, -0.55, 0.265, 1.55);
        }
        
        /* ===========================================
           STEP 2: BASE STYLES (Reset & Foundation)
           =========================================== */
        *,
        *::before,
        *::after {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        
        html {
            scroll-behavior: smooth;
            font-size: 16px;
        }
        
        body {
            font-family: var(--font-body);
            font-size: var(--font-size-base);
            font-weight: var(--font-weight-normal);
            line-height: var(--line-height-normal);
            color: var(--color-text);
            background-color: var(--color-bg);
            overflow-x: hidden;
        }
        
        h1, h2, h3, h4, h5, h6 {
            font-family: var(--font-heading);
            font-weight: var(--font-weight-semibold);
            line-height: var(--line-height-tight);
            color: var(--color-primary);
            margin-bottom: var(--space-4);
        }
        
        h1 { font-size: var(--font-size-3xl); }
        h2 { font-size: var(--font-size-2xl); }
        h3 { font-size: var(--font-size-xl); }
        h4 { font-size: var(--font-size-lg); }
        
        p {
            margin-bottom: var(--space-4);
        }
        
        a {
            color: var(--color-primary);
            text-decoration: none;
            transition: color var(--transition-fast);
        }
        
        a:hover {
            color: var(--color-primary-dark);
        }
        
        ul, ol {
            list-style-position: inside;
            margin-bottom: var(--space-4);
        }
        
        img {
            max-width: 100%;
            height: auto;
            display: block;
        }
        
        /* ===========================================
           STEP 3: LAYOUT COMPONENTS
           =========================================== */
        .container {
            width: 100%;
            max-width: var(--container-max-width);
            margin: 0 auto;
            padding: 0 var(--space-6);
        }
        
        .section {
            padding: var(--section-spacing) 0;
        }
        
        .section-title {
            text-align: center;
            margin-bottom: var(--space-12);
        }
        
        .section-title h2 {
            position: relative;
            display: inline-block;
            padding-bottom: var(--space-4);
        }
        
        .section-title h2::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 50%;
            transform: translateX(-50%);
            width: 80px;
            height: 4px;
            background-color: var(--color-secondary);
            border-radius: var(--border-radius-full);
        }
        
        .section-title p {
            color: var(--color-text-light);
            max-width: 600px;
            margin: var(--space-4) auto 0;
        }
        
        /* ===========================================
           STEP 4: REUSABLE COMPONENTS
           =========================================== */
        /* === BUTTONS === */
        .btn {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            gap: var(--space-2);
            padding: var(--space-3) var(--space-8);
            font-family: var(--font-heading);
            font-weight: var(--font-weight-semibold);
            font-size: var(--font-size-base);
            line-height: var(--line-height-normal);
            text-align: center;
            text-decoration: none;
            border: var(--border-width) solid transparent;
            border-radius: var(--border-radius);
            cursor: pointer;
            transition: all var(--transition-normal);
            user-select: none;
        }
        
        .btn-primary {
            background-color: var(--color-primary);
            color: white;
        }
        
        .btn-primary:hover {
            background-color: var(--color-primary-dark);
            color: white;
            transform: translateY(-2px);
            box-shadow: var(--shadow-md);
        }
        
        .btn-secondary {
            background-color: var(--color-secondary);
            color: var(--color-text);
        }
        
        .btn-outline {
            background-color: transparent;
            border-color: var(--color-primary);
            color: var(--color-primary);
        }
        
        .btn-outline:hover {
            background-color: var(--color-primary);
            color: white;
        }
        
        .btn-lg {
            padding: var(--space-4) var(--space-10);
            font-size: var(--font-size-lg);
        }
        
        .btn-sm {
            padding: var(--space-2) var(--space-4);
            font-size: var(--font-size-sm);
        }
        
        /* === CARDS === */
        .card {
            background-color: var(--color-bg-light);
            border-radius: var(--border-radius);
            border: var(--border-width) solid var(--color-border);
            overflow: hidden;
            transition: all var(--transition-normal);
        }
        
        .card:hover {
            transform: translateY(-5px);
            box-shadow: var(--shadow-lg);
            border-color: var(--color-primary-light);
        }
        
        .card-header {
            padding: var(--space-6);
            background-color: var(--color-primary);
            color: white;
        }
        
        .card-body {
            padding: var(--space-6);
        }
        
        .card-footer {
            padding: var(--space-4) var(--space-6);
            background-color: var(--color-bg);
            border-top: var(--border-width) solid var(--color-border);
        }
        
        /* === BADGES === */
        .badge {
            display: inline-block;
            padding: var(--space-1) var(--space-3);
            font-size: var(--font-size-xs);
            font-weight: var(--font-weight-semibold);
            line-height: var(--line-height-tight);
            text-align: center;
            white-space: nowrap;
            vertical-align: baseline;
            border-radius: var(--border-radius-full);
        }
        
        .badge-primary {
            background-color: var(--color-primary);
            color: white;
        }
        
        .badge-secondary {
            background-color: var(--color-secondary);
            color: var(--color-text);
        }
        
        /* ===========================================
           STEP 5: SITE HEADER
           =========================================== */
        .site-header {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            background-color: var(--color-bg-light);
            box-shadow: var(--shadow-sm);
            z-index: 1000;
            height: var(--header-height);
        }
        
        .header-container {
            display: flex;
            justify-content: space-between;
            align-items: center;
            height: 100%;
        }
        
        /* Logo */
        .logo {
            display: flex;
            align-items: center;
            gap: var(--space-4);
            text-decoration: none;
        }
        
        .logo-icon {
            width: 50px;
            height: 50px;
            background-color: var(--color-primary);
            color: white;
            border-radius: var(--border-radius);
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: var(--font-size-xl);
        }
        
        .logo-text h1 {
            font-size: var(--font-size-xl);
            font-weight: var(--font-weight-bold);
            margin-bottom: 0;
            line-height: 1.2;
        }
        
        .logo-text .tagline {
            font-size: var(--font-size-xs);
            color: var(--color-text-light);
            font-weight: var(--font-weight-medium);
        }
        
        /* Navigation */
        .main-nav {
            display: flex;
        }
        
        .nav-list {
            display: flex;
            list-style: none;
            gap: var(--space-6);
        }
        
        .nav-link {
            font-family: var(--font-heading);
            font-weight: var(--font-weight-medium);
            color: var(--color-text);
            text-decoration: none;
            padding: var(--space-2) 0;
            position: relative;
        }
        
        .nav-link::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 0;
            height: 2px;
            background-color: var(--color-primary);
            transition: width var(--transition-normal);
        }
        
        .nav-link:hover {
            color: var(--color-primary);
        }
        
        .nav-link:hover::after {
            width: 100%;
        }
        
        .nav-link.active {
            color: var(--color-primary);
        }
        
        .nav-link.active::after {
            width: 100%;
        }
        
        /* Mobile Toggle (akan ditampilkan nanti) */
        .mobile-toggle {
            display: none;
            background: none;
            border: none;
            font-size: var(--font-size-xl);
            color: var(--color-primary);
            cursor: pointer;
        }
        
        /* ===========================================
           STEP 6: HERO SECTION
           =========================================== */
        .hero {
            padding-top: calc(var(--header-height) + var(--space-20));
            padding-bottom: var(--space-20);
            background: linear-gradient(135deg, 
                var(--color-primary) 0%, 
                var(--color-primary-light) 100%);
            color: white;
            position: relative;
            overflow: hidden;
        }
        
        .hero::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background-image: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.05'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
        }
        
        .hero-content {
            position: relative;
            z-index: 1;
            text-align: center;
            max-width: 800px;
            margin: 0 auto;
        }
        
        .hero h1 {
            color: white;
            font-size: clamp(var(--font-size-2xl), 5vw, var(--font-size-3xl));
            margin-bottom: var(--space-6);
        }
        
        .hero p {
            font-size: var(--font-size-lg);
            margin-bottom: var(--space-8);
            opacity: 0.9;
        }
        
        .hero-buttons {
            display: flex;
            gap: var(--space-4);
            justify-content: center;
            flex-wrap: wrap;
        }
        
        /* ===========================================
           STEP 7: UTILITY CLASSES
           =========================================== */
        /* Text utilities */
        .text-center { text-align: center; }
        .text-left { text-align: left; }
        .text-right { text-align: right; }
        
        .text-primary { color: var(--color-primary); }
        .text-secondary { color: var(--color-secondary); }
        .text-light { color: var(--color-text-light); }
        .text-white { color: white; }
        
        /* Spacing utilities */
        .mt-1 { margin-top: var(--space-1); }
        .mt-2 { margin-top: var(--space-2); }
        .mt-4 { margin-top: var(--space-4); }
        .mt-8 { margin-top: var(--space-8); }
        
        .mb-1 { margin-bottom: var(--space-1); }
        .mb-2 { margin-bottom: var(--space-2); }
        .mb-4 { margin-bottom: var(--space-4); }
        .mb-8 { margin-bottom: var(--space-8); }
        
        .p-4 { padding: var(--space-4); }
        .p-6 { padding: var(--space-6); }
        .p-8 { padding: var(--space-8); }
        
        /* Display utilities */
        .d-flex { display: flex; }
        .d-block { display: block; }
        .d-inline-block { display: inline-block; }
        .d-none { display: none; }
        
        .flex-column { flex-direction: column; }
        .align-center { align-items: center; }
        .justify-center { justify-content: center; }
        .justify-between { justify-content: space-between; }
        .gap-4 { gap: var(--space-4); }
        
        /* Grid utilities */
        .grid {
            display: grid;
            gap: var(--space-6);
        }
        
        .grid-2 { grid-template-columns: repeat(2, 1fr); }
        .grid-3 { grid-template-columns: repeat(3, 1fr); }
        .grid-4 { grid-template-columns: repeat(4, 1fr); }
        
        /* ===========================================
           STEP 8: INITIAL CONTENT PLACEHOLDER
           =========================================== */
        .placeholder {
            background-color: var(--color-bg);
            border: 2px dashed var(--color-border);
            border-radius: var(--border-radius);
            padding: var(--space-20);
            text-align: center;
            color: var(--color-text-light);
        }
        
        /* ===========================================
           STEP 9: RESPONSIVE BREAKPOINTS
           =========================================== */
        @media (max-width: 768px) {
            :root {
                --section-spacing: var(--space-12);
            }
            
            .mobile-toggle {
                display: block;
            }
            
            .main-nav {
                position: fixed;
                top: var(--header-height);
                left: 0;
                width: 100%;
                background-color: var(--color-bg-light);
                box-shadow: var(--shadow);
                padding: var(--space-6);
                transform: translateY(-100%);
                opacity: 0;
                visibility: hidden;
                transition: all var(--transition-normal);
            }
            
            .main-nav.active {
                transform: translateY(0);
                opacity: 1;
                visibility: visible;
            }
            
            .nav-list {
                flex-direction: column;
                gap: var(--space-4);
            }
            
            .hero-buttons {
                flex-direction: column;
                align-items: center;
            }
            
            .btn {
                width: 100%;
                max-width: 300px;
            }
            
            .grid-2,
            .grid-3,
            .grid-4 {
                grid-template-columns: 1fr;
            }
        }
        
        @media (min-width: 769px) and (max-width: 1024px) {
            .grid-3,
            .grid-4 {
                grid-template-columns: repeat(2, 1fr);
            }
        }