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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #3d96df 100%);
    min-height: 100vh;
    color: #333;
}

.container {
    max-width: 100%;
    margin: 0 auto;
    padding: 20px;
    min-height: 100vh;
}

header {
    text-align: center;
    margin-bottom: 30px;
    padding: 20px 0;
}

header h1 {
    color: white;
    font-size: 28px;
    font-weight: 300;
    text-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.search-section {
    background: white;
    border-radius: 12px;
    padding: 30px;
    margin-bottom: 20px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.input-group label {
    font-size: 16px;
    font-weight: 500;
    color: #555;
}

.input-group input {
    padding: 15px;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    font-size: 16px;
    transition: border-color 0.3s ease;
}

.input-group input:focus {
    outline: none;
    border-color: #667eea;
}

.input-group button {
    padding: 15px;
    background: linear-gradient(135deg, #667eea 0%, #2762c9 100%);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    transition: transform 0.2s ease;
}

.input-group button:hover {
    transform: translateY(-2px);
}

.input-group button:active {
    transform: translateY(0);
}

.result-section, .error-section {
    background: white;
    border-radius: 12px;
    padding: 30px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
}

.user-info {
    margin-bottom: 10px;
    padding: 10px;
    background: #f8f9fa;
    border-radius: 8px;
}

.user-info p {
    margin-bottom: 10px;
    font-size: 12px;
}

.user-info strong {
    color: #667eea;
}

.certificate-container {
    text-align: center;
}

#certificateCanvas {
    max-width: 100%;
    height: auto;
    border: 1px solid #e0e0e0;
    border-radius: 8px;
    margin-bottom: 20px;
}

.button-group {
    display: flex;
    gap: 15px;
    justify-content: center;
    margin-top: 20px;
}

#downloadBtn, .back-btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 14px;
    cursor: pointer;
    transition: all 0.3s ease;
    flex: 1;
    max-width: 150px;
}

#downloadBtn {
    background: #28a745;
    color: white;
}

#downloadBtn:hover {
    background: #218838;
    transform: translateY(-1px);
}

.back-btn {
    background: #6c757d;
    color: white;
}

.back-btn:hover {
    background: #5a6268;
    transform: translateY(-1px);
}

.error-message {
    color: #dc3545;
    text-align: center;
    font-size: 16px;
    font-weight: 500;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .container {
        padding: 15px;
    }
    
    header h1 {
        font-size: 24px;
    }
    
    .search-section, .result-section, .error-section {
        padding: 20px;
    }
    
    #certificateCanvas {
        width: 100%;
    }
}

/* 加载动画 */
.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255,255,255,.3);
    border-radius: 50%;
    border-top-color: #fff;
    animation: spin 1s ease-in-out infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}