/* 基础样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Arial, sans-serif;
}

body {
    background: #f0f4f8;
}

/* 头部样式 */
header {
    background: #002d62;
    padding: 1rem 5%;
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1400px;
    margin: 0 auto;
}

.logo {
    height: 50px;
}

nav ul {
    display: flex;
    gap: 2rem;
    list-style: none;
}

nav a {
    color: white;
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s;
}

nav a:hover {
    color: #00c8ff;
}

/* 登录表单区域 */
.login-section {
    margin-top: 100px;
    padding: 3rem 5%;
    min-height: 70vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

.login-container {
    background: white;
    padding: 2.5rem;
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.08);
    width: 100%;
    max-width: 450px;
}

.login-title {
    text-align: center;
    color: #002d62;
    margin-bottom: 2rem;
    font-size: 1.8rem;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group input {
    width: 100%;
    padding: 12px;
    border: 2px solid #e0e0e0;
    border-radius: 6px;
    font-size: 1rem;
    transition: border-color 0.3s;
}

.form-group input:focus {
    outline: none;
    border-color: #00c8ff;
}

.login-btn {
    width: 100%;
    padding: 12px;
    background: #00c8ff;
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 1.1rem;
    cursor: pointer;
    transition: background 0.3s;
}

.login-btn:hover {
    background: #00a3d3;
}

/* 底部样式 */
footer {
    background: #002d62;
    color: white;
    padding: 3rem 5%;
}

.footer-container {
    max-width: 1400px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.footer-section h3 {
    margin-bottom: 1.5rem;
    color: #00c8ff;
    font-size: 1.2rem;
}

.footer-section ul {
    list-style: none;
}

.footer-section li {
    margin-bottom: 0.8rem;
}

.footer-section a {
    color: #ffffff;
    text-decoration: none;
    transition: color 0.3s;
}

.footer-section a:hover {
    color: #00c8ff;
}

.social-icons {
    display: flex;
    gap: 1rem;
    margin-top: 1rem;
}

.social-icons a {
    color: white;
    font-size: 1.5rem;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .header-container {
        flex-direction: column;
        gap: 1rem;
    }

    nav ul {
        gap: 1.5rem;
    }

    .login-container {
        padding: 1.5rem;
    }

    .footer-container {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    nav ul {
        flex-direction: column;
        text-align: center;
        gap: 1rem;
    }

    .login-section {
        margin-top: 150px;
    }
}