/* 全局重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', 'PingFang SC', Roboto, 'Helvetica Neue', sans-serif;
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    margin: 0;
    padding: 20px;
}

/* 卡片容器 */
.card {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-radius: 16px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.15);
    padding: 40px 45px;
    width: 100%;
    max-width: 420px;
    transition: transform 0.3s ease;
}

.card:hover {
    transform: translateY(-5px);
}

/* Logo/标题区域 */
.card .logo {
    text-align: center;
    margin-bottom: 30px;
}

.card .logo h2 {
    font-size: 26px;
    color: #2c3e50;
    font-weight: 700;
    letter-spacing: 1px;
}

.card .logo h2 span {
    color: #3498db;
}

.card .logo p {
    color: #7f8c8d;
    font-size: 14px;
    margin-top: 5px;
}

/* 表单分组 */
.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    font-size: 14px;
    font-weight: 600;
    color: #34495e;
    margin-bottom: 6px;
}

.form-group input {
    width: 100%;
    padding: 12px 15px;
    border: 2px solid #ecf0f1;
    border-radius: 10px;
    font-size: 15px;
    transition: all 0.3s;
    background-color: #f8f9fa;
    outline: none;
}

.form-group input:focus {
    border-color: #3498db;
    background-color: #ffffff;
    box-shadow: 0 0 0 4px rgba(52, 152, 219, 0.15);
}

/* 按钮 */
.btn {
    width: 100%;
    padding: 13px;
    background: #3498db;
    color: white;
    border: none;
    border-radius: 10px;
    font-size: 18px;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.3s;
    letter-spacing: 2px;
}

.btn:hover {
    background: #2980b9;
    transform: scale(0.98);
    box-shadow: 0 5px 15px rgba(52, 152, 219, 0.4);
}

.btn:active {
    transform: scale(0.95);
}

/* 底部跳转链接 */
.footer-text {
    text-align: center;
    margin-top: 25px;
    color: #7f8c8d;
    font-size: 14px;
}

.footer-text a {
    color: #3498db;
    text-decoration: none;
    font-weight: 600;
}

.footer-text a:hover {
    text-decoration: underline;
}

/* 错误提示（JS动态控制） */
.error-msg {
    color: #e74c3c;
    font-size: 13px;
    margin-top: 5px;
    display: none;
}