* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
        }
        
        body {
            background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
            min-height: 100vh;
            padding: 20px;
            color: #333;
        }
        
        .container {
            max-width: 1200px;
            margin: 0 auto;
            background-color: white;
            border-radius: 15px;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
            overflow: hidden;
        }
        
        header {
            background: linear-gradient(90deg, #4b6cb7 0%, #182848 100%);
            color: white;
            padding: 20px;
            text-align: center;
        }
        
        h1 {
            font-size: 2.5rem;
            margin-bottom: 10px;
        }
        
        .subtitle {
            font-size: 1.2rem;
            opacity: 0.9;
        }
        
        .main-content {
            display: flex;
            flex-wrap: wrap;
            min-height: 600px;
        }
        
        .form-section {
            flex: 1;
            min-width: 300px;
            padding: 30px;
            background-color: #f9f9f9;
        }
        
        .preview-section {
            flex: 1;
            min-width: 300px;
            display: flex;
            justify-content: center;
            align-items: center;
            padding: 30px;
            background-color: #f0f0f0;
        }
        
        .form-group {
            margin-bottom: 20px;
        }
        
        label {
            display: block;
            margin-bottom: 8px;
            font-weight: 600;
            color: #444;
        }
        
        input, select, textarea {
            width: 100%;
            padding: 12px;
            border: 1px solid #ddd;
            border-radius: 5px;
            font-size: 16px;
            transition: border 0.3s;
        }
        
        input:focus, select:focus, textarea:focus {
            border-color: #4b6cb7;
            outline: none;
        }
        
        textarea {
            height: 100px;
            resize: vertical;
        }
        
        .btn {
            display: block;
            width: 100%;
            padding: 15px;
            background: linear-gradient(90deg, #4b6cb7 0%, #182848 100%);
            color: white;
            border: none;
            border-radius: 5px;
            font-size: 18px;
            font-weight: 600;
            cursor: pointer;
            transition: transform 0.2s, box-shadow 0.2s;
        }
        
        .btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
        }
        
        .btn-download {
            background: linear-gradient(90deg, #11998e 0%, #38ef7d 100%);
            margin-top: 10px;
        }
        
        .certificate {
            width: 100%;
            max-width: 600px;
            background-color: white;
            border: 15px solid #f5e6ca;
            border-radius: 10px;
            padding: 40px;
            text-align: center;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
            position: relative;
            overflow: hidden;
            aspect-ratio:4 / 5.55;
        }
        
        .certificate::before {
            content: "";
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: url('../pic/bg.jpg') no-repeat;
            background-size: contain;
            z-index: 0;
        }
        
        .certificate-content {
            position: relative;
            z-index: 1;
        }
        
        .cert-title {
            font-size: 36px;
            font-weight: bold;
            color: #8b4513;
            margin-bottom: 20px;
            text-transform: uppercase;
            letter-spacing: 3px;
        }
        
        .cert-presented {
            font-size: 20px;
            margin-bottom: 10px;
            color: #666;
        }
        
        .cert-name {
            font-size: 42px;
            font-weight: bold;
            margin: 30px 0;
            color: #4b6cb7;
            text-decoration: underline;
            text-decoration-color: #f5e6ca;
        }
        
        .cert-achievement {
            font-size: 22px;
            margin: 50px 0;
            line-height: 1.5;
            color: #555;
        }
        
        .cert-date {
            font-size: 18px;
            margin-top: 80px;
            color: #666;
        }
        
        .cert-signature {
            margin-top: 50px;
            display: flex;
            justify-content: space-between;
        }
        
        .signature-box {
            flex: 1;
            text-align: center;
        }
        
        .signature-line {
            width: 200px;
            height: 1px;
            background-color: #333;
            margin: 0 auto 10px;
        }
        
        .seal {
            position: absolute;
            bottom: 80px;
            right: 70px;
            width: 120px;
            height: 120px;
            border: 4px solid #c00;
            border-radius: 50%;
            display: flex;
            justify-content: center;
            align-items: center;
            background: rgba(255, 255, 255, 0.1);
            transform: rotate(-15deg);
            z-index: 2;
        }
        
        .seal-content {
            text-align: center;
            color: #c00;
            font-weight: bold;
            font-size: 14px;
            line-height: 1.2;
        }
        
        .template-options {
            display: grid;
            grid-template-columns: repeat(2, 1fr);
            gap: 10px;
            margin-bottom: 20px;
        }
        
        .template-option {
            padding: 10px;
            border: 2px solid #ddd;
            border-radius: 5px;
            text-align: center;
            cursor: pointer;
            transition: all 0.3s;
        }
        
        .template-option:hover {
            border-color: #4b6cb7;
        }
        
        .template-option.active {
            border-color: #4b6cb7;
            background-color: #eef2ff;
        }
        
        footer {
            text-align: center;
            padding: 20px;
            background-color: #f0f0f0;
            color: #666;
            font-size: 14px;
        }
        
        @media (max-width: 768px) {
            .main-content {
                flex-direction: column;
            }
            
            .certificate {
                margin-top: 20px;
            }
            
            .template-options {
                grid-template-columns: 1fr;
            }
        }