/**
 * 布局样式 - Layout
 * 页面结构和响应式布局
 */

/* ==========================================
   Page Layout
   ========================================== */

.page {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.page-content {
    flex: 1;
}

/* ==========================================
   Grid System
   ========================================== */

.grid {
    display: grid;
    gap: var(--space-6);
}

.grid-cols-1 { grid-template-columns: repeat(1, 1fr); }
.grid-cols-2 { grid-template-columns: repeat(2, 1fr); }
.grid-cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid-cols-4 { grid-template-columns: repeat(4, 1fr); }

/* Auto-fit responsive grid */
.grid-auto {
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

.grid-auto-lg {
    grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
}

/* ==========================================
   Navbar
   ========================================== */

.navbar {
    position: sticky;
    top: 0;
    left: 0;
    right: 0;
    z-index: var(--z-sticky);
    background-color: var(--color-bg-elevated);
    border-bottom: 1px solid var(--color-bg-muted);
    padding: var(--space-4) 0;
    transition: all var(--transition-base);
    backdrop-filter: blur(18px);
    -webkit-backdrop-filter: blur(18px);
}

.navbar-scrolled {
    box-shadow: var(--shadow-sm);
}

.navbar-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-8);
}

.navbar-brand {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    font-family: var(--font-heading);
    font-size: var(--text-xl);
    font-weight: var(--font-bold);
    color: var(--color-text);
    text-decoration: none;
}

.navbar-brand:hover {
    color: var(--color-text);
}

.navbar-brand-icon {
    width: 36px;
    height: 36px;
}

.navbar-nav {
    display: flex;
    align-items: center;
    gap: var(--space-1);
}

.navbar-utilities {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    margin-left: auto;
}

.navbar-actions {
    display: flex;
    align-items: center;
    gap: var(--space-3);
}

/* Mobile menu toggle */
.navbar-toggle {
    display: none;
    padding: var(--space-2);
    background: none;
    border: none;
    cursor: pointer;
    color: var(--color-text);
}

.navbar-toggle svg {
    width: 24px;
    height: 24px;
}

/* Mobile navigation */
.navbar-mobile {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(180deg, var(--color-bg) 0%, var(--color-bg-subtle) 100%);
    z-index: var(--z-fixed);
    padding: var(--space-6);
    overflow-y: auto;
    transform: translateX(100%);
    transition: transform var(--transition-base);
}

.navbar-mobile.open {
    transform: translateX(0);
}

.navbar-mobile-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--space-8);
}

.navbar-mobile-close {
    padding: var(--space-2);
    background: none;
    border: none;
    cursor: pointer;
    color: var(--color-text);
}

.navbar-mobile-nav {
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

.theme-toggle-mobile {
    width: 100%;
    margin-bottom: var(--space-6);
    justify-content: center;
}

.navbar-mobile-link {
    display: block;
    padding: var(--space-4);
    font-family: var(--font-heading);
    font-size: var(--text-lg);
    font-weight: var(--font-medium);
    color: var(--color-text);
    border-radius: var(--radius-lg);
    transition: all var(--transition-fast);
}

.navbar-mobile-link:hover,
.navbar-mobile-link.active {
    background-color: var(--color-bg-subtle);
    color: var(--color-primary);
}

/* ==========================================
   Hero Section
   ========================================== */

.hero {
    padding: var(--space-20) 0;
    text-align: center;
}

.hero-lg {
    padding: var(--space-24) 0;
}

.hero-title {
    font-size: var(--text-5xl);
    font-weight: var(--font-bold);
    line-height: 1.1;
    margin-bottom: var(--space-6);
    letter-spacing: -0.02em;
}

.hero-subtitle {
    font-size: var(--text-xl);
    color: var(--color-text-secondary);
    max-width: 640px;
    margin: 0 auto var(--space-8);
    line-height: var(--leading-relaxed);
}

.hero-actions {
    display: flex;
    justify-content: center;
    gap: var(--space-4);
    flex-wrap: wrap;
}

/* Hero with background */
.hero-bg {
    background-color: var(--color-bg-subtle);
    border-radius: var(--radius-2xl);
    margin: var(--space-4);
}

/* ==========================================
   Section
   ========================================== */

.section {
    padding: var(--space-16) 0;
}

.section-sm {
    padding: var(--space-12) 0;
}

.section-lg {
    padding: var(--space-20) 0;
}

.section-alt {
    background-color: var(--color-bg-subtle);
}

/* ==========================================
   Footer
   ========================================== */

.footer {
    background-color: var(--color-bg-dark);
    color: var(--color-text-inverse);
    padding: var(--space-16) 0 var(--space-8);
}

.footer a {
    color: rgba(255, 255, 255, 0.7);
    transition: color var(--transition-fast);
}

.footer a:hover {
    color: var(--color-text-inverse);
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: var(--space-12);
    margin-bottom: var(--space-12);
}

.footer-brand {
    font-size: var(--text-xl);
    font-weight: var(--font-bold);
    color: var(--color-text-inverse);
    margin-bottom: var(--space-4);
}

.footer-description {
    color: rgba(255, 255, 255, 0.7);
    margin-bottom: var(--space-6);
    line-height: var(--leading-relaxed);
}

.footer-social {
    display: flex;
    gap: var(--space-3);
}

.footer-social a {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background-color: rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-lg);
    transition: all var(--transition-fast);
}

.footer-social a:hover {
    background-color: var(--color-primary);
    color: var(--color-text-inverse);
}

.footer-title {
    font-family: var(--font-heading);
    font-size: var(--text-sm);
    font-weight: var(--font-semibold);
    color: var(--color-text-inverse);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--space-4);
}

.footer-links {
    list-style: none;
    padding: 0;
    margin: 0;
}

.footer-links li {
    margin-bottom: var(--space-3);
}

.footer-links a {
    font-size: var(--text-sm);
}

.footer-divider {
    border: none;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    margin: 0 0 var(--space-8);
}

.footer-bottom {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: var(--text-sm);
    color: rgba(255, 255, 255, 0.5);
}

.footer-legal {
    display: flex;
    gap: var(--space-6);
}

/* Simple footer variant */
.footer-simple {
    padding: var(--space-8) 0;
    text-align: center;
}

.footer-simple .footer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-4);
}

/* ==========================================
   Two Column Layout
   ========================================== */

.layout-two-col {
    display: grid;
    grid-template-columns: 1fr 300px;
    gap: var(--space-12);
    align-items: start;
}

.layout-two-col-reverse {
    grid-template-columns: 300px 1fr;
}

/* Sidebar */
.sidebar {
    position: sticky;
    top: calc(var(--space-20));
}

.sidebar-section {
    margin-bottom: var(--space-8);
}

.sidebar-title {
    font-size: var(--text-sm);
    font-weight: var(--font-semibold);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-text-muted);
    margin-bottom: var(--space-4);
}

/* ==========================================
   Article/Blog Layout
   ========================================== */

.article-layout {
    max-width: var(--content-width);
    margin: 0 auto;
    padding: var(--space-12) var(--space-4);
}

.article-header {
    margin-bottom: var(--space-12);
}

.article-category {
    display: inline-block;
    margin-bottom: var(--space-4);
}

.article-title {
    font-size: var(--text-4xl);
    line-height: 1.2;
    margin-bottom: var(--space-6);
}

.article-meta {
    display: flex;
    align-items: center;
    gap: var(--space-6);
    color: var(--color-text-secondary);
    font-size: var(--text-sm);
}

.article-author {
    display: flex;
    align-items: center;
    gap: var(--space-3);
}

.article-content {
    font-size: var(--text-lg);
    line-height: var(--leading-loose);
}

.article-content h2 {
    margin-top: var(--space-12);
    margin-bottom: var(--space-6);
}

.article-content h3 {
    margin-top: var(--space-8);
    margin-bottom: var(--space-4);
}

.article-content p {
    margin-bottom: var(--space-6);
}

.article-content img {
    border-radius: var(--radius-lg);
    margin: var(--space-8) 0;
}

.article-content ul,
.article-content ol {
    margin-bottom: var(--space-6);
    padding-left: var(--space-6);
}

.article-content li {
    margin-bottom: var(--space-3);
}

/* ==========================================
   Card Grid Layout
   ========================================== */

.card-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-6);
}

.card-grid-2 {
    grid-template-columns: repeat(2, 1fr);
}

.card-grid-4 {
    grid-template-columns: repeat(4, 1fr);
}

/* ==========================================
   Feature Section
   ========================================== */

.features {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-8);
}

.feature {
    text-align: center;
    padding: var(--space-6);
}

.feature-title {
    font-size: var(--text-xl);
    margin-bottom: var(--space-3);
}

.feature-description {
    color: var(--color-text-secondary);
    line-height: var(--leading-relaxed);
}

/* ==========================================
   CTA Section
   ========================================== */

.cta {
    text-align: center;
    padding: var(--space-16);
    background-color: var(--color-bg-subtle);
    border-radius: var(--radius-2xl);
}

.cta-title {
    font-size: var(--text-3xl);
    margin-bottom: var(--space-4);
}

.cta-description {
    font-size: var(--text-lg);
    color: var(--color-text-secondary);
    max-width: 500px;
    margin: 0 auto var(--space-8);
}

/* Newsletter CTA */
.newsletter {
    max-width: 480px;
    margin: 0 auto;
}

.newsletter-form {
    display: flex;
    gap: var(--space-3);
}

.newsletter-form .form-input {
    flex: 1;
}

/* ==========================================
   Responsive Breakpoints
   ========================================== */

/* Tablet */
@media (max-width: 1024px) {
    .navbar-nav {
        display: none;
    }

    .navbar-toggle {
        display: block;
    }

    .footer-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .layout-two-col,
    .layout-two-col-reverse {
        grid-template-columns: 1fr;
    }

    .sidebar {
        position: static;
    }

    .card-grid,
    .features {
        grid-template-columns: repeat(2, 1fr);
    }

    .card-grid-4 {
        grid-template-columns: repeat(2, 1fr);
    }

    .hero-title {
        font-size: var(--text-4xl);
    }

    .navbar-theme-toggle {
        width: 40px;
        height: 40px;
        padding: var(--space-2);
    }

    .navbar-theme-toggle .theme-toggle-label {
        display: none;
    }
}

/* Mobile */
@media (max-width: 768px) {
    .container {
        padding-left: var(--space-4);
        padding-right: var(--space-4);
    }

    .navbar-utilities,
    .navbar-actions {
        gap: var(--space-2);
    }

    .section {
        padding: var(--space-12) 0;
    }

    .hero {
        padding: var(--space-12) 0;
    }

    .hero-title {
        font-size: var(--text-3xl);
    }

    .hero-subtitle {
        font-size: var(--text-lg);
    }

    .hero-actions {
        flex-direction: column;
        align-items: stretch;
    }

    .hero-actions .btn {
        width: 100%;
    }

    .card-grid,
    .card-grid-2,
    .card-grid-4,
    .features,
    .grid-cols-2,
    .grid-cols-3,
    .grid-cols-4 {
        grid-template-columns: 1fr;
    }

    .footer-grid {
        grid-template-columns: 1fr;
        gap: var(--space-8);
    }

    .footer-bottom {
        flex-direction: column;
        gap: var(--space-4);
        text-align: center;
    }

    .footer-legal {
        justify-content: center;
    }

    .article-title {
        font-size: var(--text-2xl);
    }

    .article-content {
        font-size: var(--text-base);
    }

    .article-meta {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--space-3);
    }

    .newsletter-form {
        flex-direction: column;
    }

    .cta {
        padding: var(--space-10) var(--space-6);
    }

    .cta-title {
        font-size: var(--text-2xl);
    }
}

/* Small mobile */
@media (max-width: 480px) {
    html {
        font-size: 14px;
    }

    .hero-title {
        font-size: var(--text-2xl);
    }
}