/* ===== 设计系统变量 ===== */
:root {
    /* 颜色 - 基于设计规范 */
    --surface: #f9f9ff;
    --surface-dim: #cfdaf2;
    --surface-bright: #f9f9ff;
    --surface-container-lowest: #ffffff;
    --surface-container-low: #f0f3ff;
    --surface-container: #e7eeff;
    --surface-container-high: #dee8ff;
    --surface-container-highest: #d8e3fb;
    --on-surface: #111c2d;
    --on-surface-variant: #434655;
    --outline: #737686;
    --outline-variant: #c3c6d7;
    --primary: #004ac6;
    --on-primary: #ffffff;
    --primary-container: #2563eb;
    --on-primary-container: #eeefff;
    --inverse-primary: #b4c5ff;
    --secondary: #515f74;
    --on-secondary: #ffffff;
    --secondary-container: #d5e3fc;
    --tertiary: #943700;
    --error: #ba1a1a;
    --error-container: #ffdad6;
    /* 圆角 */
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-2xl: 1.5rem;
    /* 间距 */
    --gutter-mobile: 16px;
    --gutter-desktop: 24px;
    --container-max: 1280px;
    /* 玻璃效果 */
    --glass-bg: rgba(255, 255, 255, 0.7);
    --glass-border: rgba(255, 255, 255, 0.4);
    --glass-blur: 20px;
}

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

body {
    background: linear-gradient(135deg, var(--surface) 0%, var(--surface-container-low) 100%);
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
    color: var(--on-surface);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* 主容器 */
.main-container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--gutter-mobile);
    width: 100%;
}

@media (min-width: 768px) {
    .main-container {
        padding: 0 var(--gutter-desktop);
    }
}

/* ===== 玻璃态组件 ===== */
.glass-card {
    background: var(--glass-bg);
    backdrop-filter: blur(var(--glass-blur));
    border-radius: var(--radius-lg);
    border: 1px solid var(--glass-border);
    box-shadow: 0 8px 32px 0 rgba(31, 38, 135, 0.07);
}

.glass-card-hover {
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

    .glass-card-hover:hover {
        transform: translateY(-2px);
        box-shadow: 0 12px 40px 0 rgba(31, 38, 135, 0.12);
    }

/* 导航栏 */
.navbar-glossy {
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--glass-border);
    box-shadow: none;
    position: sticky;
    top: 0;
    z-index: 1000;
}

.navbar-brand {
    font-size: 1.4rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-container) 100%);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent !important;
    letter-spacing: -0.01em;
}

.nav-link {
    font-weight: 500;
    font-size: 0.95rem;
    color: var(--on-surface-variant) !important;
    transition: color 0.2s ease;
}

    .nav-link:hover {
        color: var(--primary) !important;
    }

/* 按钮样式 */
.btn-primary-glass {
    background: var(--primary-container);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    padding: 10px 24px;
    font-weight: 500;
    font-size: 0.9rem;
    transition: all 0.2s ease;
    cursor: pointer;
}

    .btn-primary-glass:hover {
        background: var(--primary);
        transform: scale(1.02);
        box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3);
    }

.btn-outline-glass {
    background: transparent;
    border: 1px solid var(--outline-variant);
    border-radius: var(--radius-md);
    padding: 8px 20px;
    font-weight: 500;
    color: var(--on-surface-variant);
    transition: all 0.2s ease;
    cursor: pointer;
}

    .btn-outline-glass:hover {
        background: rgba(37, 99, 235, 0.1);
        border-color: var(--primary-container);
        transform: scale(1.02);
    }

/* 输入框 */
.input-glass {
    background: rgba(255, 255, 255, 0.5);
    border: 1px solid var(--outline-variant);
    border-radius: var(--radius-md);
    padding: 12px 16px;
    font-size: 1rem;
    transition: all 0.2s ease;
    width: 100%;
}

    .input-glass:focus {
        outline: none;
        border-color: var(--primary-container);
        box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
        background: white;
    }

/* 卡片 - 知识容器 */
.knowledge-card {
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(8px);
    border-radius: var(--radius-lg);
    border: 1px solid rgba(255, 255, 255, 0.5);
    transition: all 0.2s ease;
    cursor: pointer;
    height: 100%;
}

    .knowledge-card:hover {
        transform: translateY(-3px);
        background: white;
        box-shadow: 0 8px 24px rgba(0, 0, 0, 0.08);
        border-color: var(--outline-variant);
    }

/* 标签和徽章 */
.chip {
    display: inline-flex;
    align-items: center;
    padding: 4px 12px;
    background: rgba(37, 99, 235, 0.1);
    border-radius: 32px;
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--primary);
}

/* 页脚 */
.footer-glass {
    background: rgba(255, 255, 255, 0.6);
    backdrop-filter: blur(10px);
    border-top: 1px solid var(--glass-border);
    margin-top: auto;
}

.footer-link {
    color: var(--on-surface-variant);
    text-decoration: none;
    font-size: 0.75rem;
    transition: color 0.2s;
}

    .footer-link:hover {
        color: var(--primary);
    }

/* 加载动画 */
.spinner-glass {
    width: 40px;
    height: 40px;
    border: 3px solid var(--outline-variant);
    border-top-color: var(--primary-container);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

/* 响应式工具 */
@media (max-width: 768px) {
    .hide-mobile {
        display: none;
    }

    .full-width-mobile {
        width: 100%;
    }

    .stack-mobile {
        flex-direction: column;
    }
}