<!DOCTYPE html>
<html lang="id">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Kalkulator Luas Persegi</title>
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.4.0/css/all.min.css">
    <style>
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
        }

        body {
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: #fff;
            min-height: 100vh;
            display: flex;
            justify-content: center;
            align-items: center;
            padding: 20px;
        }

        .container {
            max-width: 800px;
            width: 100%;
            background: rgba(255, 255, 255, 0.1);
            border-radius: 20px;
            padding: 40px;
            backdrop-filter: blur(10px);
            border: 1px solid rgba(255, 255, 255, 0.2);
            box-shadow: 0 15px 35px rgba(0, 0, 0, 0.3);
        }

        header {
            text-align: center;
            margin-bottom: 40px;
        }

        h1 {
            font-size: 3rem;
            margin-bottom: 15px;
            color: #ffdd00;
            text-shadow: 0 0 15px rgba(255, 221, 0, 0.5);
        }

        .subtitle {
            font-size: 1.3rem;
            color: #e0e0e0;
            margin-bottom: 10px;
        }

        .content {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 40px;
            align-items: center;
        }

        .calculator-section {
            background: rgba(255, 255, 255, 0.05);
            padding: 30px;
            border-radius: 15px;
            border: 1px solid rgba(255, 255, 255, 0.1);
        }

        .formula-box {
            background: rgba(0, 0, 0, 0.3);
            padding: 20px;
            border-radius: 10px;
            text-align: center;
            margin-bottom: 25px;
            border: 1px solid rgba(255, 255, 255, 0.1);
        }

        .formula {
            font-size: 2rem;
            font-weight: bold;
            color: #4ecdc4;
        }

        .input-group {
            margin-bottom: 20px;
        }

        .input-group label {
            display: block;
            margin-bottom: 10px;
            color: #e0e0e0;
            font-size: 1.1rem;
            font-weight: 500;
        }

        .input-group input {
            width: 100%;
            padding: 15px;
            border-radius: 10px;
            border: 2px solid rgba(255, 255, 255, 0.2);
            background: rgba(0, 0, 0, 0.3);
            color: white;
            font-size: 1.2rem;
            transition: all 0.3s ease;
        }

        .input-group input:focus {
            outline: none;
            border-color: #4ecdc4;
            box-shadow: 0 0 0 3px rgba(78, 205, 196, 0.3);
            transform: scale(1.02);
        }

        .calculate-btn {
            width: 100%;
            padding: 16px;
            background: linear-gradient(135deg, #4ecdc4, #45b7d1);
            border: none;
            border-radius: 10px;
            color: white;
            font-size: 1.3rem;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s ease;
            margin-top: 10px;
        }

        .calculate-btn:hover {
            transform: translateY(-3px);
            box-shadow: 0 8px 20px rgba(78, 205, 196, 0.4);
            background: linear-gradient(135deg, #45b7d1, #4ecdc4);
        }

        .calculate-btn:active {
            transform: translateY(1px);
        }

        .result {
            margin-top: 25px;
            padding: 20px;
            background: rgba(78, 205, 196, 0.15);
            border-radius: 10px;
            border-left: 5px solid #4ecdc4;
            font-size: 1.4rem;
            text-align: center;
            display: none;
            animation: fadeIn 0.5s ease;
        }

        .visualization {
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
        }

        .square-container {
            position: relative;
            width: 200px;
            height: 200px;
            margin: 20px 0;
        }

        .square {
            width: 100%;
            height: 100%;
            background: linear-gradient(135deg, #ff6b6b, #ff9e2c);
            border: 4px solid white;
            box-shadow: 0 10px 25px rgba(0, 0, 0, 0.3);
            transition: all 0.5s ease;
            position: relative;
        }

        .side-label {
            position: absolute;
            background: rgba(0, 0, 0, 0.7);
            color: white;
            padding: 5px 10px;
            border-radius: 5px;
            font-size: 0.9rem;
            font-weight: bold;
        }

        .side-top {
            top: -35px;
            left: 50%;
            transform: translateX(-50%);
        }

        .side-bottom {
            bottom: -35px;
            left: 50%;
            transform: translateX(-50%);
        }

        .side-left {
            left: -60px;
            top: 50%;
            transform: translateY(-50%) rotate(-90deg);
        }

        .side-right {
            right: -60px;
            top: 50%;
            transform: translateY(-50%) rotate(-90deg);
        }

        .explanation {
            margin-top: 30px;
            padding: 25px;
            background: rgba(255, 255, 255, 0.05);
            border-radius: 15px;
            border: 1px solid rgba(255, 255, 255, 0.1);
        }

        .explanation h3 {
            color: #ffdd00;
            margin-bottom: 15px;
            font-size: 1.5rem;
        }

        .explanation p {
            line-height: 1.6;
            color: #e0e0e0;
            margin-bottom: 10px;
        }

        .examples {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 15px;
            margin-top: 20px;
        }

        .example-card {
            background: rgba(255, 255, 255, 0.05);
            padding: 15px;
            border-radius: 10px;
            text-align: center;
            border: 1px solid rgba(255, 255, 255, 0.1);
            transition: transform 0.3s ease;
            cursor: pointer;
        }

        .example-card:hover {
            transform: translateY(-5px);
            background: rgba(255, 255, 255, 0.1);
        }

        @keyframes fadeIn {
            from { opacity: 0; transform: translateY(10px); }
            to { opacity: 1; transform: translateY(0); }
        }

        @keyframes pulse {
            0% { transform: scale(1); }
            50% { transform: scale(1.05); }
            100% { transform: scale(1); }
        }

        @media (max-width: 768px) {
            .content {
                grid-template-columns: 1fr;
            }
            
            h1 {
                font-size: 2.2rem;
            }
            
            .examples {
                grid-template-columns: 1fr;
            }
        }
    </style>
</head>
<body>
    <div class="container">
        <header>
            <h1><i class="fas fa-square"></i> Kalkulator Luas Persegi</h1>
            <p class="subtitle">Hitung luas persegi dengan mudah dan cepat</p>
        </header>

        <div class="content">
            <div class="calculator-section">
                <div class="formula-box">
                    <div class="formula">L = s × s</div>
                    <p style="margin-top: 10px; color: #ccc;">Luas = sisi × sisi</p>
                </div>
                
                <div class="input-group">
                    <label for="square-side"><i class="fas fa-ruler"></i> Panjang Sisi (s):</label>
                    <input type="number" id="square-side" placeholder="Masukkan panjang sisi" step="any" min="0">
                </div>
                
                <button class="calculate-btn" onclick="calculateSquareArea()">
                    <i class="fas fa-calculator"></i> Hitung Luas
                </button>
                
                <div class="result" id="square-result">
                    <i class="fas fa-check-circle"></i> <span id="result-text"></span>
                </div>
            </div>

            <div class="visualization">
                <h3 style="margin-bottom: 20px; color: #ffdd00;">Visualisasi Persegi</h3>
                <div class="square-container">
                    <div class="square" id="animated-square"></div>
                    <div class="side-label side-top" id="top-label">s</div>
                    <div class="side-label side-bottom" id="bottom-label">s</div>
                    <div class="side-label side-left" id="left-label">s</div>
                    <div class="side-label side-right" id="right-label">s</div>
                </div>
                <p style="text-align: center; color: #e0e0e0; margin-top: 20px;">
                    Semua sisi persegi memiliki panjang yang sama
                </p>
            </div>
        </div>

        <div class="explanation">
            <h3><i class="fas fa-lightbulb"></i> Penjelasan Luas Persegi</h3>
            <p>Persegi adalah bangun datar dua dimensi yang memiliki empat sisi dengan panjang yang sama dan empat sudut siku-siku (90°).</p>
            <p><strong>Rumus Luas Persegi:</strong> L = s × s</p>
            <p>Dimana:
                <br>• L = Luas persegi
                <br>• s = Panjang sisi persegi
            </p>
            
            <div class="examples">
                <div class="example-card" onclick="setExample(5)">
                    <strong>Contoh 1</strong>
                    <p>s = 5 cm</p>
                    <p>L = 5 × 5 = 25 cm²</p>
                </div>
                <div class="example-card" onclick="setExample(8)">
                    <strong>Contoh 2</strong>
                    <p>s = 8 m</p>
                    <p>L = 8 × 8 = 64 m²</p>
                </div>
                <div class="example-card" onclick="setExample(12)">
                    <strong>Contoh 3</strong>
                    <p>s = 12 cm</p>
                    <p>L = 12 × 12 = 144 cm²</p>
                </div>
            </div>
        </div>
    </div>

    <script>
        // Fungsi untuk menghitung luas persegi
        function calculateSquareArea() {
            const side = parseFloat(document.getElementById('square-side').value);
            const resultElement = document.getElementById('square-result');
            const resultText = document.getElementById('result-text');
            const square = document.getElementById('animated-square');
            
            if (isNaN(side) || side <= 0) {
                resultText.innerHTML = "Masukkan panjang sisi yang valid!";
                resultElement.style.display = 'block';
                resultElement.style.background = 'rgba(255, 100, 100, 0.15)';
                resultElement.style.borderLeftColor = '#ff6b6b';
                return;
            }
            
            const area = side * side;
            
            // Update hasil
            resultText.innerHTML = `Luas Persegi = <strong>${area.toFixed(2)}</strong> satuan²`;
            resultElement.style.display = 'block';
            resultElement.style.background = 'rgba(78, 205, 196, 0.15)';
            resultElement.style.borderLeftColor = '#4ecdc4';
            
            // Update visualisasi
            updateVisualization(side);
            
            // Animasi
            square.style.animation = 'pulse 0.5s ease';
            setTimeout(() => {
                square.style.animation = '';
            }, 500);
        }
        
        // Fungsi untuk memperbarui visualisasi
        function updateVisualization(side) {
            const labels = document.querySelectorAll('.side-label');
            labels.forEach(label => {
                label.textContent = side;
            });
            
            const square = document.getElementById('animated-square');
            square.style.transform = 'scale(1)';
        }
        
        // Fungsi untuk mengisi contoh
        function setExample(sideValue) {
            document.getElementById('square-side').value = sideValue;
            calculateSquareArea();
        }
        
        // Event listener untuk input agar bisa menggunakan Enter
        document.getElementById('square-side').addEventListener('keypress', function(e) {
            if (e.key === 'Enter') {
                calculateSquareArea();
            }
        });
        
        // Animasi saat halaman dimuat
        document.addEventListener('DOMContentLoaded', function() {
            const square = document.getElementById('animated-square');
            square.style.transform = 'scale(0)';
            square.style.transition = 'transform 0.8s ease';
            
            setTimeout(() => {
                square.style.transform = 'scale(1)';
            }, 300);
            
            // Set contoh default
            setExample(10);
        });
    </script>
</body>
</html>
