CSS Advanced & Responsive

by oktaviardi pratama

HTML

<!-- 1. Media Queries -->
    <h2>1. Media Queries (Responsive)</h2>
    <div class="section">
        <p><strong>Desktop:</strong> 3 kolom biru | <strong>Mobile:</strong> 1 kolom merah</p>
        <p><em>(Kecilkan layar browser untuk melihat perubahan)</em></p>
        <div class="responsive-grid">
            <div class="responsive-box">Kolom 1</div>
            <div class="responsive-box">Kolom 2</div>
            <div class="responsive-box">Kolom 3</div>
        </div>
    </div>

    <!-- 2. Pseudo-Class -->
    <h2>2. Pseudo-Class</h2>
    <div class="section">
        <p>Hover, Focus, Active pada button:</p>
        <button class="btn">Hover Saya</button>
        <button class="btn">Klik Saya</button>

        <p style="margin-top: 20px;">:nth-child() pada list:</p>
        <div class="list-item">Item 1 (Ganjil - Abu)</div>
        <div class="list-item">Item 2 (Genap - Biru)</div>
        <div class="list-item">Item 3 (Ganjil - Abu)</div>
        <div class="list-item">Item 4 (Genap - Biru)</div>
    </div>

    <!-- 3. Pseudo-Element -->
    <h2>3. Pseudo-Element</h2>
    <div class="section">
        <div class="decorated-box">
            Kotak dengan hiasan ::before (bintang) dan ::after (teks Premium)
        </div>
    </div>

    <!-- 4. Transitions -->
    <h2>4. Transitions</h2>
    <div class="section">
        <p>Hover kotak hijau untuk melihat animasi halus:</p>
        <div class="transition-box"></div>
    </div>

    <!-- 5. Animations -->
    <h2>5. Animations (Keyframes)</h2>
    <div class="section">
        <p class="animate-fade">Teks ini muncul dengan Fade In</p>
        <br>
        <span class="animate-pulse">Tombol Berdenyut (Pulse)</span>
        <br><br>
        <div class="animate-spin"></div>
        <p>Loading Spinner</p>
    </div>

CSS

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

        body {
            font-family: Arial, sans-serif;
            background: #f4f4f4;
            padding: 20px;
        }

        h2 {
            margin: 30px 0 15px;
            padding-bottom: 10px;
            border-bottom: 3px solid #3498db;
        }

        .section {
            background: white;
            padding: 20px;
            margin-bottom: 20px;
            border-radius: 8px;
            box-shadow: 0 2px 5px rgba(0,0,0,0.1);
        }

        /* --- 1. MEDIA QUERIES (Responsive) --- */
        .responsive-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr); /* 3 kolom default */
            gap: 15px;
        }
        .responsive-box {
            background: #3498db;
            color: white;
            padding: 30px;
            text-align: center;
            border-radius: 8px;
        }

        /* Mobile: 1 kolom saat layar < 768px */
        @media (max-width: 768px) {
            .responsive-grid {
                grid-template-columns: 1fr;
            }
            .responsive-box {
                background: #e74c3c; /* Warna berubah di mobile */
            }
        }

        /* --- 2. PSEUDO-CLASS --- */
        .btn {
            display: inline-block;
            padding: 12px 25px;
            background: #2c3e50;
            color: white;
            text-decoration: none;
            border-radius: 5px;
            margin: 5px;
            border: none;
            cursor: pointer;
            font-size: 16px;
        }
        .btn:hover {
            background: #3498db; /* Hover state */
            transform: scale(1.05);
        }
        .btn:focus {
            outline: 3px solid #f39c12; /* Focus state */
        }
        .btn:active {
            background: #1a252f; /* Click state */
        }

        /* Pseudo-class :nth-child */
       ...