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

:root {
    --primary-color: #3498db;
    --secondary-color: #2c3e50;
    --accent-color: #e74c3c;
    --background-color: #f5f7fa;
    --text-color: #333;
    --light-text: #7f8c8d;
    --card-bg: #ffffff;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --shadow-hover: rgba(0, 0, 0, 0.15);
    --transition-speed: 0.3s;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

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

@keyframes rotate {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

body {
    font-family: 'Microsoft YaHei', Arial, sans-serif;
    background-color: var(--background-color);
    background-image: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    padding: 20px;
    color: var(--text-color);
    transition: background-color var(--transition-speed) ease;
}

.container {
    background-color: var(--card-bg);
    border-radius: 12px;
    box-shadow: 0 8px 24px var(--shadow-color);
    padding: 30px;
    max-width: 500px;
    width: 100%;
    text-align: center;
    transition: all var(--transition-speed) ease;
    animation: fadeIn 0.8s ease-out;
    position: relative;
    overflow: hidden;
}

.container::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
}

.container:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 30px var(--shadow-hover);
}

h1 {
    color: var(--secondary-color);
    margin-bottom: 25px;
    font-size: 28px;
    font-weight: 600;
    position: relative;
    display: inline-block;
}

h1::after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 3px;
    background-color: var(--primary-color);
    border-radius: 3px;
}

.qr-container {
    position: relative;
    margin: 20px 0;
}

#qrImage {
    max-width: 100%;
    height: auto;
    border: 5px solid #fff;
    box-shadow: 0 4px 12px var(--shadow-color);
    border-radius: 8px;
    transition: all var(--transition-speed) ease;
    display: block;
    margin: 0 auto;
}

#qrImage:hover {
    transform: scale(1.03);
    box-shadow: 0 6px 16px var(--shadow-hover);
}

.loader {
    display: none;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 40px;
    height: 40px;
    border: 4px solid rgba(0, 0, 0, 0.1);
    border-radius: 50%;
    border-top-color: var(--primary-color);
    animation: rotate 1s linear infinite;
}

.loading .loader {
    display: block;
}

.loading #qrImage {
    opacity: 0.5;
}

.footer {
    margin-top: 25px;
    font-size: 14px;
    color: var(--light-text);
}

.footer span {
    display: inline-block;
    position: relative;
}

.footer span::after {
    content: '';
    position: absolute;
    width: 0;
    height: 1px;
    bottom: -2px;
    left: 0;
    background-color: var(--primary-color);
    transition: width var(--transition-speed) ease;
}

.container:hover .footer span::after {
    width: 100%;
}

.error-message {
    background-color: #ffecec;
    color: var(--accent-color);
    border-radius: 8px;
    padding: 12px;
    margin-top: 15px;
    display: none;
    border-left: 4px solid var(--accent-color);
}

.retry-button {
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 4px;
    padding: 8px 16px;
    margin-top: 10px;
    cursor: pointer;
    transition: background-color var(--transition-speed) ease;
    display: none;
}

.retry-button:hover {
    background-color: #2980b9;
}

@media (max-width: 768px) {
    .container {
        padding: 20px;
    }
    
    h1 {
        font-size: 24px;
        margin-bottom: 20px;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 15px;
    }
    
    h1 {
        font-size: 22px;
    }
    
    #qrImage {
        border-width: 3px;
    }
}

@media (prefers-color-scheme: dark) {
    :root {
        --background-color: #1a1e24;
        --card-bg: #2c3e50;
        --text-color: #ecf0f1;
        --light-text: #bdc3c7;
        --shadow-color: rgba(0, 0, 0, 0.3);
        --shadow-hover: rgba(0, 0, 0, 0.4);
    }
    
    body {
        background-image: linear-gradient(135deg, #1a1e24 0%, #2c3e50 100%);
    }
    
    .error-message {
        background-color: rgba(231, 76, 60, 0.15);
    }
}