/*
 * 德尚网络 · 全站样式
 * 主题：代码绿 #10B981 + 开发灰 #1F2937，辅以科技蓝 #3B82F6 与创新橙 #F97316
 * 设计方向：软件服务型官网，强调技术、专业、创新与高效
 */

:root {
  --color-primary: #10b981;
  --color-dark: #1f2937;
  --color-deep: #0f172a;
  --color-secondary: #3b82f6;
  --color-accent: #f97316;
  --color-muted: #4b5563;
  --color-border: #e5e7eb;
  --color-light: #ffffff;
  --color-background: #f8fafc;

  --font-sans: "Alibaba PuHuiTi", "Inter", "SF Pro Display", "PingFang SC", "Microsoft YaHei", sans-serif;

  --spacing-xxs: 4px;
  --spacing-xs: 8px;
  --spacing-sm: 12px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 40px;
  --spacing-xxl: 56px;

  --border-radius: 12px;
  --border-radius-lg: 20px;
  --shadow-sm: 0 4px 12px rgba(15, 23, 42, 0.06);
  --shadow: 0 14px 40px rgba(15, 23, 42, 0.12);
  --shadow-strong: 0 18px 60px rgba(15, 23, 42, 0.18);

  --transition: all 0.25s ease;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  color: var(--color-dark);
  background: var(--color-background);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: var(--transition);
}

a:hover {
  color: var(--color-secondary);
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

.container {
  width: min(1200px, 94vw);
  margin: 0 auto;
}

.main-content {
  background: var(--color-background);
}

/* 导航 */
.site-header,
.header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(15, 23, 42, 0.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}

.nav,
.navbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-sm) 0;
  gap: var(--spacing-md);
}

.brand,
.logo {
  color: #ecfeff;
  font-weight: 700;
  font-size: 1.2rem;
  letter-spacing: 0.5px;
  white-space: nowrap;
}

.nav-menu {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

.nav-menu li {
  position: relative;
}

.nav-link {
  color: #e2e8f0;
  padding: var(--spacing-sm) var(--spacing-xs);
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-weight: 500;
}

.nav-link:hover,
.nav-item:hover > .nav-link {
  color: #fff;
}

.nav-link::after {
  content: "";
  display: block;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--color-primary), var(--color-secondary));
  transition: var(--transition);
  border-radius: 999px;
}

.nav-item:hover .nav-link::after,
.nav-group:hover > .nav-link::after {
  width: 100%;
}

.dropdown,
.dropdown-menu {
  position: absolute;
  top: 120%;
  left: 0;
  min-width: 180px;
  background: #0b1221;
  border: 1px solid rgba(255, 255, 255, 0.06);
  border-radius: var(--border-radius);
  box-shadow: var(--shadow-sm);
  padding: var(--spacing-sm) 0;
  opacity: 0;
  pointer-events: none;
  transform: translateY(6px);
  transition: var(--transition);
}

.nav-group:hover .dropdown,
.nav-item:hover .dropdown-menu {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}

.dropdown a,
.dropdown-menu a,
.dropdown-menu .dropdown-item a {
  display: block;
  padding: var(--spacing-sm) var(--spacing-md);
  color: #e2e8f0;
  font-size: 0.95rem;
}

.dropdown a:hover,
.dropdown-menu a:hover,
.dropdown-menu .dropdown-item a:hover {
  color: #fff;
  background: rgba(16, 185, 129, 0.12);
}

/* Hero */
.hero {
  position: relative;
  padding: var(--spacing-xxl) 0 var(--spacing-xl);
  overflow: hidden;
  background: radial-gradient(circle at 20% 20%, rgba(59, 130, 246, 0.15), transparent 40%),
    radial-gradient(circle at 80% 0%, rgba(16, 185, 129, 0.18), transparent 36%),
    linear-gradient(135deg, #0f172a 0%, #111827 55%, #0b1221 100%);
  color: #e5e7eb;
}

.hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background: url("../images/abstract/hero_background_1.png") center/cover no-repeat;
  opacity: 0.12;
  pointer-events: none;
}

.hero-grid {
  position: relative;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: var(--spacing-xl);
  align-items: center;
  z-index: 1;
}

.hero-lead {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.hero-title {
  font-size: clamp(2.2rem, 4vw, 3.2rem);
  margin: 0;
  color: #fff;
}

.hero-meta {
  color: #cbd5e1;
  font-size: 1.02rem;
}

.code-panel {
  background: #0b1221;
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-lg);
  color: #c7d2fe;
  box-shadow: var(--shadow);
  font-family: "JetBrains Mono", "SFMono-Regular", Consolas, monospace;
}

.code-line {
  display: block;
  margin-bottom: var(--spacing-xs);
}

.code-line .k { color: #34d399; }
.code-line .s { color: #60a5fa; }
.code-line .n { color: #f59e0b; }

/* 章节与网格 */
.section {
  padding: var(--spacing-xl) 0;
}

.section.alt {
  background: #fff;
}

.section.dark {
  background: var(--color-deep);
  color: #e5e7eb;
}

.section.tight {
  padding: var(--spacing-lg) 0;
}

.section-header {
  text-align: center;
  margin-bottom: var(--spacing-lg);
}

.section-title {
  font-size: clamp(1.6rem, 3vw, 2.4rem);
  margin: 0 0 var(--spacing-sm);
  color: var(--color-dark);
}

.section-subtitle {
  margin: 0;
  color: var(--color-muted);
  font-size: 1.02rem;
}

.grid {
  display: grid;
  gap: var(--spacing-lg);
}

.grid-2 {
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

.grid-3 {
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
}

.grid-4 {
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.grid-cols-3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.grid-cols-2-md {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.grid-cols-2 {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.media-block {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: var(--spacing-xl);
  align-items: center;
}

/* 卡片与组件 */
.card {
  background: var(--color-light);
  border-radius: var(--border-radius);
  padding: var(--spacing-md);
  box-shadow: var(--shadow-sm);
  border: 1px solid rgba(15, 23, 42, 0.04);
}

.card img {
  border-radius: calc(var(--border-radius) - 4px);
  margin-bottom: var(--spacing-md);
}

.card.solid {
  background: linear-gradient(145deg, rgba(16, 185, 129, 0.12), rgba(59, 130, 246, 0.1));
  border: 1px solid rgba(16, 185, 129, 0.3);
}

.icon-circle {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: rgba(16, 185, 129, 0.12);
  color: var(--color-primary);
  display: grid;
  place-items: center;
  font-weight: 700;
  margin-bottom: var(--spacing-sm);
}

.button-row {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 18px;
  border-radius: 999px;
  border: 1px solid transparent;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  text-decoration: none;
}

.btn-primary {
  background: linear-gradient(120deg, var(--color-primary), var(--color-secondary));
  color: #fff;
  box-shadow: var(--shadow-sm);
}

.btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow);
}

.btn-outline {
  background: transparent;
  color: var(--color-primary);
  border-color: rgba(16, 185, 129, 0.4);
}

.btn-outline:hover {
  background: rgba(16, 185, 129, 0.08);
  color: var(--color-primary);
}

.btn-ghost {
  color: var(--color-primary);
  background: rgba(16, 185, 129, 0.08);
  border-color: transparent;
}

.btn-ghost:hover {
  background: rgba(16, 185, 129, 0.14);
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 12px;
  background: rgba(16, 185, 129, 0.14);
  color: var(--color-primary);
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.95rem;
}

.list-inline {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

.tech-section .stack-list {
  justify-content: center;
  margin: 0 auto var(--spacing-lg);
  max-width: 980px;
}

.pill {
  display: inline-flex;
  padding: 8px 12px;
  background: #eef2ff;
  color: #4338ca;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.95rem;
}

.tag {
  display: inline-flex;
  padding: 6px 10px;
  background: rgba(16, 185, 129, 0.12);
  color: var(--color-primary);
  border-radius: 8px;
  font-weight: 600;
  font-size: 0.9rem;
}

.capability-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: var(--spacing-lg);
}

.capability-item {
  text-align: center;
  background: var(--color-light);
  border-radius: var(--border-radius);
  padding: var(--spacing-md);
  border: 1px solid rgba(15, 23, 42, 0.06);
  box-shadow: var(--shadow-sm);
}

.capability-item img {
  max-height: 72px;
  margin: 0 auto var(--spacing-sm);
}

.capability-item h4 {
  margin: 0 0 var(--spacing-xs);
  color: var(--color-dark);
}

.capability-item p {
  margin: 0;
  color: var(--color-muted);
}

.stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: var(--spacing-md);
}

.stat {
  background: linear-gradient(145deg, rgba(16, 185, 129, 0.1), rgba(59, 130, 246, 0.08));
  border: 1px solid rgba(16, 185, 129, 0.18);
  border-radius: var(--border-radius);
  padding: var(--spacing-md);
  text-align: center;
  box-shadow: var(--shadow-sm);
}

.value {
  font-size: 2rem;
  font-weight: 800;
  color: var(--color-dark);
}

.label {
  color: var(--color-muted);
  margin-top: var(--spacing-xs);
}

.timeline {
  display: grid;
  gap: var(--spacing-md);
  margin-top: var(--spacing-md);
}

.timeline-item {
  position: relative;
  padding-left: var(--spacing-lg);
  border-left: 3px solid rgba(16, 185, 129, 0.3);
}

.timeline-item::before {
  content: "";
  position: absolute;
  left: -9px;
  top: 8px;
  width: 14px;
  height: 14px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
  border-radius: 50%;
  box-shadow: 0 0 0 6px rgba(16, 185, 129, 0.16);
}

.table {
  width: 100%;
  border-collapse: collapse;
  background: var(--color-light);
  box-shadow: var(--shadow-sm);
  border-radius: var(--border-radius);
  overflow: hidden;
}

.table th,
.table td {
  padding: var(--spacing-md);
  border: 1px solid var(--color-border);
  text-align: left;
}

.table th {
  background: rgba(16, 185, 129, 0.12);
  color: var(--color-dark);
  font-weight: 700;
}

/* 页眉/子页标题 */
.page-header {
  background: linear-gradient(135deg, rgba(16, 185, 129, 0.9), rgba(59, 130, 246, 0.9));
  color: #fff;
  padding: var(--spacing-xl) 0;
  position: relative;
  overflow: hidden;
}

.page-header::after {
  content: "";
  position: absolute;
  inset: 0;
  background: url("../images/abstract/hero_background_2.png") center/cover no-repeat;
  opacity: 0.15;
}

.page-header .container {
  position: relative;
  z-index: 1;
}

/* 页脚 */
.footer {
  background: #0b1221;
  color: #cbd5e1;
  padding: var(--spacing-xl) 0 var(--spacing-lg);
  margin-top: var(--spacing-xl);
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--spacing-lg);
}

.footer h4 {
  margin-top: 0;
  color: #fff;
}

.footer ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: var(--spacing-xs);
}

.footer a { color: #e2e8f0; }
.footer a:hover { color: #fff; }

.footer-bottom,
.copyright {
  margin-top: var(--spacing-lg);
  padding-top: var(--spacing-md);
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  color: #94a3b8;
  text-align: center;
}

/* 表单 */
input,
textarea,
select {
  font-family: var(--font-sans);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  padding: 12px;
  width: 100%;
  background: #fff;
  transition: var(--transition);
}

input:focus,
textarea:focus,
select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(16, 185, 129, 0.2);
}

/* 响应式 */
@media (max-width: 1024px) {
  .grid-cols-2-md,
  .grid-cols-3 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 768px) {
  .nav,
  .navbar {
    flex-wrap: wrap;
  }

  .nav-menu {
    flex-wrap: wrap;
    gap: var(--spacing-sm);
  }

  .grid-cols-2-md,
  .grid-cols-3,
  .grid-3,
  .grid-2 {
    grid-template-columns: repeat(1, minmax(0, 1fr));
  }

  .hero {
    padding: var(--spacing-xl) 0;
  }
}

@media (max-width: 540px) {
  .btn,
  .button-row {
    width: 100%;
  }

  .button-row {
    flex-direction: column;
    align-items: stretch;
  }

  .code-panel {
    padding: var(--spacing-md);
  }
}