/* 全局变量 */
:root {
    --primary-gradient: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%);
    --primary-color: #6366f1;
    --secondary-color: #2c3e50;
    --success-color: #2ecc71;
    --error-color: #e74c3c;
    --text-color: #333;
    --border-color: #ddd;
    --card-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
    --hover-shadow: 0 8px 20px rgba(99, 102, 241, 0.2);
    --border-radius: 8px;
    --border-radius-lg: 12px;
    --transition-speed: 0.3s;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background: linear-gradient(135deg, #f5f7fa 0%, #e4e7eb 100%);
    color: var(--text-color);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    animation: gradientBG 15s ease infinite;
    background-size: 400% 400%;
}

/* 登录容器样式 */
.login-container {
    background: rgba(255, 255, 255, 0.98);
    border-radius: var(--border-radius-lg);
    padding: 40px;
    width: 100%;
    max-width: 400px;
    box-shadow: var(--card-shadow);
    backdrop-filter: blur(10px);
    animation: containerFadeIn 0.6s ease-out;
}

/* 品牌 Logo */
.brand-logo {
    width: 80px;
    height: 80px;
    background: var(--primary-gradient);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 20px;
    box-shadow: var(--hover-shadow);
    animation: logoScale 0.6s ease-out;
}

.brand-logo span {
    color: white;
    font-size: 32px;
    font-weight: bold;
    user-select: none;
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
}

/* 表单组样式 */
.form-group {
    margin-bottom: 20px;
    position: relative;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    color: var(--secondary-color);
    font-weight: 500;
}

.form-group input {
    width: 100%;
    padding: 12px 12px 12px 40px;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 16px;
    transition: all var(--transition-speed);
}

.form-group input:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
    outline: none;
}

/* 图标样式 */
.form-group::before {
    font-family: "Font Awesome 5 Free";
    position: absolute;
    left: 12px;
    top: 42px;
    color: #64748b;
    font-size: 16px;
}

.username-group::before {
    content: '👤';
}

.password-group::before {
    content: '🔒';
}

/* 密码显示/隐藏按钮 */
.password-toggle {
    position: absolute;
    right: 12px;
    top: 42px;
    width: 24px;
    height: 24px;
    background: transparent;
    border: none;
    cursor: pointer;
    opacity: 0.6;
    transition: opacity 0.3s;
}

.password-toggle:hover {
    opacity: 1;
}

.password-toggle.show {
    background: url('eye.svg') no-repeat center;
}

.password-toggle.hide {
    background: url('eye-off.svg') no-repeat center;
}

/* 按钮样式 */
button {
    width: 100%;
    padding: 12px;
    background: var(--primary-gradient);
    color: white;
    border: none;
    border-radius: var(--border-radius);
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-speed);
    box-shadow: 0 4px 6px rgba(99, 102, 241, 0.2);
}

button:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(99, 102, 241, 0.3);
}

button:active {
    transform: translateY(0);
}

/* 消息提示样式 */
#message {
    margin-top: 15px;
    padding: 12px;
    border-radius: var(--border-radius);
    text-align: center;
    font-size: 14px;
    animation: fadeIn 0.3s ease;
}

.error {
    background-color: rgba(231, 76, 60, 0.1);
    color: var(--error-color);
    border: 1px solid rgba(231, 76, 60, 0.2);
}

.success {
    background-color: rgba(46, 204, 113, 0.1);
    color: var(--success-color);
    border: 1px solid rgba(46, 204, 113, 0.2);
}

/* 动画效果 */
@keyframes gradientBG {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

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

@keyframes logoScale {
    from {
        transform: scale(0.8);
        opacity: 0;
    }
    to {
        transform: scale(1);
        opacity: 1;
    }
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

/* 响应式调整 */
@media (max-width: 480px) {
    .login-container {
        padding: 20px;
    }
    
    .brand-logo {
        width: 60px;
        height: 60px;
    }
    
    .brand-logo span {
        font-size: 24px;
    }
    
    .form-group input {
        padding: 10px 10px 10px 36px;
        font-size: 14px;
    }
}

/* 暗色模式支持 */
@media (prefers-color-scheme: dark) {
    body {
        background: linear-gradient(135deg, #1a1c2c 0%, #2d3436 100%);
    }
    
    .login-container {
        background: rgba(30, 32, 44, 0.98);
        color: #fff;
    }
    
    .form-group label {
        color: #e2e8f0;
    }
    
    .form-group input {
        background: rgba(255, 255, 255, 0.05);
        border-color: rgba(255, 255, 255, 0.1);
        color: #fff;
    }
    
    .form-group input:focus {
        border-color: var(--primary-color);
    }
}