/* 全局样式重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* 根元素变量定义 */
:root {
    --primary-color: #4f46e5;
    --primary-hover: #4338ca;
    --success-color: #10b981;
    --error-color: #ef4444;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --border-color: #e5e7eb;
    --bg-color: #f9fafb;
    --card-bg: #ffffff;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 
                 'Microsoft YaHei', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-primary);
    line-height: 1.6;
}

/* 容器 */
.container {
    width: 100%;
    max-width: 480px;
    padding: 20px;
}

/* 登录卡片 */
.login-card {
    background: var(--card-bg);
    border-radius: 16px;
    box-shadow: var(--shadow-lg);
    padding: 40px;
    animation: fadeInUp 0.5s ease-out;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Logo区域 */
.logo-section {
    text-align: center;
    margin-bottom: 32px;
}

.system-title {
    font-size: 28px;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 8px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.subtitle {
    font-size: 14px;
    color: var(--text-secondary);
}

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

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

.form-group label {
    font-size: 14px;
    font-weight: 500;
    color: var(--text-primary);
}

.form-group input {
    padding: 12px 16px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 14px;
    transition: all 0.3s ease;
    outline: none;
}

.form-group input:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

.form-group input::placeholder {
    color: #9ca3af;
}

.form-hint {
    font-size: 12px;
    color: var(--text-secondary);
    margin-top: -4px;
}

/* 表单选项 */
.form-options {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 14px;
    margin-top: -8px;
}

.checkbox-container {
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    color: var(--text-secondary);
}

.checkbox-container input[type="checkbox"] {
    width: 16px;
    height: 16px;
    cursor: pointer;
}

/* 按钮样式 */
.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    outline: none;
}

.btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    box-shadow: 0 4px 12px rgba(79, 70, 229, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(79, 70, 229, 0.4);
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-primary:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

/* 链接样式 */
.link {
    color: var(--primary-color);
    text-decoration: none;
    font-size: 14px;
    font-weight: 500;
    transition: color 0.3s ease;
}

.link:hover {
    color: var(--primary-hover);
    text-decoration: underline;
}

/* 表单底部 */
.form-footer {
    text-align: center;
    font-size: 14px;
    color: var(--text-secondary);
    margin-top: 8px;
}

.form-footer .separator {
    margin: 0 12px;
    color: var(--border-color);
}

/* 消息提示 */
.message {
    position: fixed;
    top: 20px;
    left: 50%;
    transform: translateX(-50%);
    padding: 16px 24px;
    border-radius: 8px;
    box-shadow: var(--shadow-lg);
    font-size: 14px;
    font-weight: 500;
    z-index: 1000;
    animation: slideDown 0.3s ease-out;
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translate(-50%, -20px);
    }
    to {
        opacity: 1;
        transform: translate(-50%, 0);
    }
}

.message.success {
    background-color: var(--success-color);
    color: white;
}

.message.error {
    background-color: var(--error-color);
    color: white;
}

/* 响应式设计 */
@media (max-width: 640px) {
    .container {
        padding: 16px;
    }
    
    .login-card {
        padding: 28px 24px;
    }
    
    .system-title {
        font-size: 24px;
    }
}

/* 加载动画 */
@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

.loading {
    display: inline-block;
    width: 16px;
    height: 16px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 0.6s linear infinite;
}