* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Microsoft YaHei', Arial, sans-serif;
    background-color: #f5f5f5;
    line-height: 1.6;
}

/* 顶部导航栏样式 */
.header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    padding: 20px 0;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.header-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 20px;
}

/* 标题样式 */
.system-title {
    color: white;
    font-size: 2.5em;
    font-weight: bold;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
    letter-spacing: 2px;
}

/* 登录区域样式 */
.login-section {
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 15px;
}

/* 登录选项卡样式 */
.login-tabs {
    display: flex;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 25px;
    padding: 5px;
    backdrop-filter: blur(10px);
}

.tab-button {
    padding: 8px 20px;
    border: none;
    background: transparent;
    color: rgba(255, 255, 255, 0.7);
    cursor: pointer;
    border-radius: 20px;
    transition: all 0.3s ease;
    font-size: 14px;
    font-weight: 500;
}

.tab-button.active {
    background: white;
    color: #667eea;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
}

.tab-button:hover:not(.active) {
    color: white;
    background: rgba(255, 255, 255, 0.1);
}

/* 登录表单样式 */
.login-form {
    background: white;
    padding: 30px;
    border-radius: 15px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    width: 320px;
    display: none;
}

.login-form.active {
    display: block;
    animation: fadeInUp 0.5s ease;
}

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

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.form-title {
    text-align: center;
    margin-bottom: 25px;
    color: #333;
    font-size: 1.3em;
    font-weight: bold;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    color: #555;
    font-weight: 500;
}

.form-group input {
    width: 100%;
    padding: 12px 15px;
    border: 2px solid #e1e1e1;
    border-radius: 8px;
    font-size: 14px;
    transition: border-color 0.3s ease;
}

.form-group input:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.login-btn {
    width: 100%;
    padding: 12px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: bold;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.login-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
}

/* 主要内容区域 */
.main-content {
    max-width: 1200px;
    margin: 40px auto;
    padding: 0 20px;
    text-align: center;
}

.welcome-text {
    background: white;
    padding: 60px 40px;
    border-radius: 15px;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.08);
}

.welcome-text h2 {
    color: #333;
    font-size: 2em;
    margin-bottom: 20px;
}

.welcome-text p {
    color: #666;
    font-size: 1.1em;
    max-width: 600px;
    margin: 0 auto;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .header-container {
        flex-direction: column;
        gap: 20px;
    }

    .system-title {
        font-size: 2em;
        text-align: center;
    }

    .login-section {
        align-items: center;
    }

    .login-form {
        width: 280px;
    }
}

.flash-messages {
    position: fixed;
    top: 20px;
    right: 820px;
    z-index: 1000;
}

.flash-message {
    padding: 10px 15px;
    margin-bottom: 10px;
    border-radius: 4px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.flash-success {
    background-color: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.flash-error {
    background-color: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

.flash-warning {
    background-color: #fff3cd;
    color: #856404;
    border: 1px solid #ffeaa7;
}

.flash-info {
    background-color: #d1ecf1;
    color: #0c5460;
    border: 1px solid #bee5eb;
}