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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f8f9fa;
}

header {
    background-color: #2c3e50;
    color: white;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.logo {
    font-size: 1.8rem;
    font-weight: bold;
}

nav ul {
    display: flex;
    list-style: none;
}

nav ul li {
    margin-left: 1.5rem;
}

nav ul li a {
    color: white;
    text-decoration: none;
    transition: color 0.3s;
}

nav ul li a:hover, nav ul li a.active {
    color: #4fc3f7;
}

main {
    max-width: 1200px;
    margin: 2rem auto;
    padding: 0 1rem;
}

/* 轮播背景图片美化 */
.hero-slider {
    position: relative;
    height: 350px;
    overflow: hidden;
    margin-bottom: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 16px rgba(0,0,0,0.08);
}
.slide {
    position: absolute;
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 2.5rem;
    color: #fff;
    background-size: cover;
    background-position: center;
    opacity: 0;
    transition: opacity 1s;
    z-index: 1;
}
.slide.active {
    opacity: 1;
    z-index: 2;
}

.slide:nth-child(1) { background-color: #3498db; }
.slide:nth-child(2) { background-color: #2ecc71; }
.slide:nth-child(3) { background-color: #e74c3c; }

.product-intro, .cta-section, .print-container,
.login-container, .register-container, .contact-container {
    text-align: center;
    padding: 2rem 0;
}

.product-intro h2 {
    margin-bottom: 1rem;
    color: #2c3e50;
}

.cta-section {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

.btn {
    padding: 0.8rem 1.5rem;
    background-color: #3498db;
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 1rem;
    transition: background-color 0.3s;
}

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

/* 表单左右布局优化 */
.form-group {
    display: flex;
    align-items: center;
    margin-bottom: 1.5rem;
    justify-content: flex-start;
}
.form-group label {
    flex: 0 0 120px;
    margin-bottom: 0;
    text-align: right;
    margin-right: 1rem;
    font-weight: bold;
}
.form-group input,
.form-group textarea {
    flex: 1 1 auto;
    width: auto;
    min-width: 0;
    padding: 0.8rem;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 1rem;
}

/* 响应式：小屏幕下恢复竖排 */
@media (max-width: 600px) {
    .form-group {
        flex-direction: column;
        align-items: stretch;
    }
    .form-group label {
        text-align: left;
        margin-bottom: 0.5rem;
        margin-right: 0;
    }
}

.hidden {
    display: none;
}

footer {
    background-color: #2c3e50;
    color: white;
    text-align: center;
    padding: 1rem;
    margin-top: 2rem;
}

/* Responsive design */
@media (max-width: 768px) {
    header {
        flex-direction: column;
        padding: 1rem;
    }
    
    nav ul {
        margin-top: 1rem;
        flex-wrap: wrap;
        justify-content: center;
    }
    
    nav ul li {
        margin: 0.5rem;
    }
    
    .hero-slider {
        height: 300px;
    }
    
    .cta-section {
        flex-direction: column;
        align-items: center;
    }
}