/* 全局变量定义 */
:root {
    --primary-color: #6366f1; /* 靛蓝 */
    --primary-hover: #4f46e5;
    --secondary-color: #ec4899; /* 粉红 */
    --bg-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --text-main: #1f2937;
    --text-muted: #6b7280;
    --border-color: #e5e7eb;
    --input-bg: #f9fafb;
    --white: #ffffff;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

/* 基础重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background-color: #f3f4f6;
    color: var(--text-main);
    height: 100vh;
    overflow: hidden; /* 防止滚动条出现 */
}

a {
    text-decoration: none;
    color: var(--primary-color);
    transition: color 0.2s;
}

a:hover {
    color: var(--primary-hover);
}

/* 主容器布局 */
.main-container {
    display: flex;
    height: 100%;
    width: 100%;
}

/* 左侧品牌区 */
.brand-section {
    flex: 1;
    background: var(--bg-gradient);
    color: var(--white);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    padding: 60px;
    position: relative;
    overflow: hidden;
}

/* 背景装饰圆圈 */
.brand-section::before {
    content: '';
    position: absolute;
    top: -100px;
    right: -100px;
    width: 400px;
    height: 400px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
}

.brand-section::after {
    content: '';
    position: absolute;
    bottom: -50px;
    left: -50px;
    width: 300px;
    height: 300px;
    background: rgba(255, 255, 255, 0.05);
    border-radius: 50%;
}

.brand-content {
    z-index: 1;
    max-width: 500px;
}

.logo-area {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 40px;
    font-size: 1.5rem;
    font-weight: 800;
}

.logo-icon {
    font-size: 2rem;
}

.brand-content h1 {
    font-size: 3.5rem;
    line-height: 1.1;
    margin-bottom: 20px;
    font-weight: 800;
}

.brand-content p {
    font-size: 1.1rem;
    opacity: 0.9;
    margin-bottom: 40px;
    line-height: 1.6;
}

.feature-list {
    list-style: none;
}

.feature-list li {
    display: flex;
    align-items: flex-start;
    gap: 15px;
    margin-bottom: 25px;
}

.feature-list .icon {
    font-size: 1.5rem;
    background: rgba(255, 255, 255, 0.2);
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 10px;
}

.feature-list strong {
    display: block;
    font-size: 1.1rem;
    margin-bottom: 4px;
}

.feature-list p {
    font-size: 0.9rem;
    margin: 0;
    opacity: 0.8;
}

.brand-footer {
    z-index: 1;
    font-size: 0.9rem;
    opacity: 0.7;
}

/* 右侧表单区 */
.form-section {
    flex: 1;
    background-color: var(--white);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 40px;
    overflow-y: auto; /* 允许小屏幕滚动 */
}

.form-wrapper {
    width: 100%;
    max-width: 450px;
}

.form-header {
    margin-bottom: 30px;
    text-align: center;
}

.form-header h3 {
    font-size: 2rem;
    color: var(--text-main);
    margin-bottom: 10px;
}

.form-header p {
    color: var(--text-muted);
}

.link-login {
    font-weight: 600;
}

/* 表单样式 */
.register-form {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.input-group label {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-main);
}

.input-field {
    position: relative;
    display: flex;
    align-items: center;
}

.input-icon {
    position: absolute;
    left: 15px;
    color: var(--text-muted);
    font-size: 1.1rem;
}

.input-field input {
    width: 100%;
    padding: 12px 15px 12px 45px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background-color: var(--input-bg);
    font-size: 1rem;
    transition: all 0.3s;
    outline: none;
}

.input-field input:focus {
    border-color: var(--primary-color);
    background-color: var(--white);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

/* 密码强度条 */
.password-strength {
    display: flex;
    gap: 5px;
    margin-top: 5px;
}

.strength-bar {
    height: 4px;
    flex: 1;
    background-color: #e5e7eb;
    border-radius: 2px;
    transition: background-color 0.3s;
}

/* 模拟静态强度显示 */
.strength-bar.weak { background-color: #ef4444; }
.strength-bar.medium { background-color: #f59e0b; }
.strength-bar.strong { background-color: #10b981; }

/* 复选框 */
.checkbox-group {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 0.9rem;
    color: var(--text-muted);
}

.checkbox-group input {
    width: 16px;
    height: 16px;
    accent-color: var(--primary-color);
    cursor: pointer;
}

/* 提交按钮 */
.btn-submit {
    background-color: var(--primary-color);
    color: var(--white);
    border: none;
    padding: 14px;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.3s, transform 0.1s;
    margin-top: 10px;
}

.btn-submit:hover {
    background-color: var(--primary-hover);
}

.btn-submit:active {
    transform: scale(0.98);
}

/* 分割线 */
.divider {
    display: flex;
    align-items: center;
    text-align: center;
    color: var(--text-muted);
    font-size: 0.9rem;
    margin: 10px 0;
}

.divider::before,
.divider::after {
    content: '';
    flex: 1;
    border-bottom: 1px solid var(--border-color);
}

.divider span {
    padding: 0 10px;
}

/* 社交登录 */
.social-login {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}

.btn-social {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background-color: var(--white);
    color: var(--text-main);
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s;
}

.btn-social:hover {
    background-color: #f9fafb;
    border-color: #d1d5db;
}

.btn-social.google span {
    color: #ea4335;
    font-weight: bold;
}

.btn-social.wechat span {
    color: #07c160;
    font-weight: bold;
}

/* 响应式适配 */
@media (max-width: 900px) {
    .brand-section {
        display: none; /* 小屏幕隐藏左侧品牌区 */
    }
    
    .form-section {
        padding: 20px;
    }
}