/* --- 基础与布局样式 --- */
body {
    font-family: 'PingFang SC', 'Helvetica Neue', 'Arial', sans-serif;
    background: linear-gradient(135deg, #e0eafc 0%, #cfdef3 100%);
    display: flex;
    justify-content: center;
    align-items: center;
    /* --- 修复长页面边距问题的关键 --- */
    min-height: 100vh; /* 使用最小高度，允许内容撑开 */
    margin: 0;
    padding: 20px 0; /* 给手机端上下留出至少 20px 的呼吸空间 */
    box-sizing: border-box;
}

.login-container {
    background-color: #ffffff;
    padding: 40px;
    border-radius: 16px;
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.1);
    width: 90%; /* 手机端宽度占 90% */
    max-width: 420px;
    text-align: center;
    transition: transform 0.3s ease;
    /* 防止容器太长时溢出 */
    margin: auto;
}

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

h2 {
    color: #2c3e50;
    margin-bottom: 25px;
    font-size: 1.6em;
    font-weight: 600;
    border-bottom: 3px solid #3498db;
    display: inline-block;
    padding-bottom: 8px;
}

/* --- 表单组件样式 --- */
.input-group {
    margin-bottom: 18px;
    text-align: left;
}

.input-group label {
    display: block;
    margin-bottom: 6px;
    color: #34495e;
    font-weight: 600;
    font-size: 0.85em;
}

/* 输入框通用样式 */
.input-group input {
    width: 100%;
    padding: 12px;
    border: 1px solid #dcdfe6;
    border-radius: 8px;
    box-sizing: border-box;
    font-size: 14px;
    transition: all 0.3s;
}

/* 针对 xm-select 的微调，使其符合你的 UI 风格 */
#school-select {
    background-color: #fff;
    border-radius: 8px;
    text-align: left;
}

.input-group input:focus {
    border-color: #3498db;
    outline: none;
    box-shadow: 0 0 8px rgba(52, 152, 219, 0.2);
}

/* 验证码行布局 */
.captcha-row {
    display: flex;
    gap: 10px;
}

/* --- 按钮系列 --- */
.login-btn, .register-btn, .reset-btn {
    width: 100%;
    padding: 14px;
    border: none;
    border-radius: 8px;
    font-size: 1.1em;
    cursor: pointer;
    font-weight: bold;
    transition: all 0.3s;
    margin-top: 10px;
    box-sizing: border-box;
}

.login-btn { background-color: #3498db; color: white; letter-spacing: 4px; }
.login-btn:hover { background-color: #2980b9; box-shadow: 0 5px 15px rgba(52, 152, 219, 0.3); }

.register-btn { background-color: #2ecc71; color: white; }
.register-btn:hover { background-color: #27ae60; }

.reset-btn {background-color: #e03429; color: white; letter-spacing: 4px; }
.reset-btn:hover { background-color: #c73d33; }

.send-code-btn {
    width: 140px;
    background: #f8f9fa;
    border: 1px solid #dcdfe6;
    border-radius: 8px;
    cursor: pointer;
    color: #3498db;
    font-size: 0.85em;
    transition: 0.3s;
}
.send-code-btn:disabled { color: #999; cursor: not-allowed; }

/* --- 底部链接与响应式 --- */
.footer-links {
    margin-top: 25px;
    font-size: 0.85em;
    color: #7f8c8d;
}

.footer-links a {
    color: #3498db;
    text-decoration: none;
    margin: 0 5px;
}

@media (max-width: 768px) {
    .login-container {
        width: 85%;
        padding: 30px 20px;
    }
    h2 { font-size: 1.4em; }
}