/* 全局样式重置 */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}
body {
    background: linear-gradient(135deg, #f1f5f9 0%, #e2e8f0 100%);
    height: 100vh;
    display: flex;
    flex-direction: column;
    overflow: hidden; /* 防止出现滚动条 */
    position: relative;
}

/* 装饰性几何元素 */
.geo-shape {
    position: fixed;
    opacity: 0.06;
    pointer-events: none;
    z-index: 0;
}

.geo-1 {
    top: -100px;
    right: -100px;
    width: 400px;
    height: 400px;
    background: #31b0d5;
    border-radius: 50% 0 50% 50%;
}

.geo-2 {
    bottom: -50px;
    left: -50px;
    width: 300px;
    height: 300px;
    background: #31b0d5;
    border-radius: 50%;
}

.geo-3 {
    top: 30%;
    right: 10%;
    width: 150px;
    height: 150px;
    border: 3px solid #31b0d5;
    border-radius: 50%;
}

.geo-4 {
    bottom: 25%;
    left: 15%;
    width: 100px;
    height: 100px;
    background: #31b0d5;
    transform: rotate(45deg);
}
/* 顶部导航栏 */
header {
    position: relative;
    color: #ecf0f1;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    z-index: 100;
    transition: background-color 0.3s ease;
}
.header-title {
    font-size: 1.5rem;
    font-weight: 600;
}
.header-link {
    color: rgba(255,255,255,0.9);
    text-decoration: none;
    font-size: 1.2rem;
    padding: 0.5rem 0.75rem;
    border-radius: 4px;
    transition: all 0.15s ease;
}
.header-link:hover {
    color: white;
    background: rgba(255,255,255,0.15);
}
/* 主容器 */
main {
    position: relative;
    z-index: 1;
    flex: 1;
    padding: 2rem;
    overflow-y: auto;
    display: flex;
    justify-content: center; /* 内容居中 */
}
/* 知识库看板（图标网格） */
.dashboard-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); /* 响应式网格 */
    gap: 2rem;
    max-width: 1200px;
    width: 100%;
    padding: 2rem 0;
    align-content: start; /* 网格内容顶部对齐 */
}
/* 系统图标卡片 */
.system-card {
    background-color: #fff;
    border-radius: 12px;
    padding: 2.5rem 1.5rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
    transition: all 0.3s ease;
    cursor: pointer;
    border: 2px solid transparent;
    text-decoration: none; /* 去除链接下划线 */
    color: inherit;
    max-width: 250px;
}
.system-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 12px 20px rgba(0,0,0,0.15);
    border-color: rgba(0,0,0,0.1);
}
.system-icon {
    font-size: 3.5rem;
    margin-bottom: 1.2rem;
    transition: transform 0.3s;
}
.system-card:hover .system-icon {
    transform: scale(1.1);
}
.system-name {
    font-size: 1.2rem;
    font-weight: 600;
    color: #2c3e50;
    text-align: center;
}