/* =====================================================
   全频谱认知架构网站 · 统一样式系统 v2.1
   Linear 风格优化版 · 2026-04-20
   遵循 DESIGN.md 规范
   ===================================================== */

/* ===== 1. CSS Variables ===== */
:root {
  /* 主色 Brand Blue（统一蓝色系） */
  --color-primary:       #2563eb;
  --color-primary-dark:  #1d4ed8;
  --color-primary-light: #eff6ff;
  --color-primary-muted: #bfdbfe;

  /* 中性色 Neutral Scale（Linear 风格灰度） */
  --color-black:   #0a0a0a;
  --color-gray-9:  #1e293b;
  --color-gray-8:  #334155;
  --color-gray-7:  #475569;
  --color-gray-6:  #64748b;
  --color-gray-5:  #94a3b8;
  --color-gray-4:  #cbd5e1;
  --color-gray-3:  #e2e8f0;
  --color-gray-2:  #f1f5f9;
  --color-gray-1:  #f8fafc;
  --color-white:   #ffffff;

  /* 功能色 Semantic */
  --color-success:        #16a34a;
  --color-success-bg:     #f0fdf4;
  --color-success-border: #bbf7d0;
  --color-warning:        #d97706;
  --color-warning-bg:     #fffbeb;
  --color-warning-border: #fde68a;
  --color-danger:         #dc2626;
  --color-danger-bg:      #fef2f2;
  --color-danger-border:  #fecaca;
  --color-info:           #0891b2;
  --color-info-bg:        #ecfeff;
  --color-info-border:    #a5f3fc;

  /* Hero 深色背景 */
  --hero-from:   #0f172a;
  --hero-to:     #1e3a5f;
  --hero-text:   #e2e8f0;
  --hero-muted:  #94a3b8;

  /* Linear 风格：更克制的阴影 */
  --shadow-xs: 0 1px 2px rgba(0,0,0,0.04);
  --shadow-sm: 0 2px 6px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 16px rgba(0,0,0,0.06);
  --shadow-lg: 0 8px 32px rgba(0,0,0,0.08);
  --shadow-xl: 0 16px 48px rgba(0,0,0,0.10);

  /* 间距系统（8px 基准） */
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 20px;
  --space-6: 24px;
  --space-8: 32px;
  --space-10: 40px;
  --space-12: 48px;

  /* 圆角（更克制） */
  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;

  /* 兼容别名（逐步废弃） */
  --primary:       var(--color-primary);
  --primary-dark:  var(--color-primary-dark);
  --primary-light: var(--color-primary-light);
  --accent:        var(--color-primary);
  --accent-light:  var(--color-primary-light);
  --bg:            var(--color-gray-1);
  --surface:       var(--color-white);
  --text:          var(--color-gray-9);
  --text-muted:    var(--color-gray-6);
  --border:        var(--color-gray-3);
  --shadow:        var(--shadow-sm);
  --green:         var(--color-success);
  --green-bg:      var(--color-success-bg);
  --green-border:  var(--color-success-border);
  --yellow-bg:     var(--color-warning-bg);
  --yellow-border: var(--color-warning-border);
  --yellow-text:   #92400e;
  --warning-bg:    var(--color-warning-bg);
  --warning-border:var(--color-warning-border);
  --red:           var(--color-danger);
  --red-bg:        var(--color-danger-bg);
  --purple:        #7c3aed;
  --purple-bg:     #f5f3ff;
}

/* ===== 2. Reset ===== */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

/* ===== 3. Base ===== */
html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
  background: var(--color-white);
  color: var(--color-gray-9);
  line-height: 1.7;
  font-size: 14px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: opacity 0.15s;
}

a:hover {
  opacity: 0.8;
  text-decoration: none;
}

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

/* ===== 4. Header ===== */
.header {
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--color-gray-3);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.header-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 var(--space-8);
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}

/* ===== 5. Logo ===== */
.logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
  color: var(--color-gray-9);
  flex-shrink: 0;
}

.logo:hover {
  text-decoration: none;
  opacity: 1;
}

.logo-icon {
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, #0f172a 0%, #1e3a5f 100%);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-weight: 700;
  font-size: 13px;
  flex-shrink: 0;
  letter-spacing: -0.5px;
}

.logo-text {
  display: flex;
  flex-direction: column;
  gap: 1px;
}

.logo-name {
  font-size: 15px;
  font-weight: 700;
  color: var(--color-gray-9);
  line-height: 1.2;
  letter-spacing: -0.2px;
}

.logo-tagline {
  font-size: 10px;
  color: var(--color-gray-5);
  line-height: 1.2;
  letter-spacing: 0.3px;
}

/* ===== 6. Navigation ===== */
.nav {
  display: flex;
  align-items: center;
  gap: 2px;
}

.nav a {
  padding: 6px var(--space-3);
  color: var(--color-gray-7);
  text-decoration: none;
  font-size: 13.5px;
  font-weight: 500;
  border-radius: var(--radius-md);
  transition: background 0.15s, color 0.15s, opacity 0.15s;
  white-space: nowrap;
}

.nav a:hover {
  background: var(--color-gray-1);
  color: var(--color-gray-9);
  opacity: 1;
  text-decoration: none;
}

.nav a.active {
  background: var(--color-primary);
  color: #fff;
  font-weight: 600;
}

/* ===== 7. Sub Navigation ===== */
.sub-nav {
  display: flex;
  gap: 4px;
  margin-bottom: var(--space-8);
  background: var(--color-white);
  border-bottom: 1px solid var(--color-gray-3);
  position: sticky;
  top: 60px;
  z-index: 999;
}

.sub-nav a {
  padding: 10px var(--space-5);
  background: transparent;
  color: var(--color-gray-6);
  text-decoration: none;
  border-radius: var(--radius-md) var(--radius-md) 0 0;
  font-size: 13.5px;
  font-weight: 500;
  transition: color 0.15s, background 0.15s;
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
}

.sub-nav a:hover {
  color: var(--color-gray-9);
  background: var(--color-gray-1);
  opacity: 1;
  text-decoration: none;
}

.sub-nav a.active {
  color: var(--color-primary);
  font-weight: 600;
  border-bottom-color: var(--color-primary);
}

/* ===== 8. Main Container ===== */
.main-container {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 var(--space-8);
}

/* ===== 9. Sections ===== */
.section {
  padding: var(--space-12) 0;
}

.section-header {
  text-align: center;
  margin-bottom: var(--space-8);
}

.section-label {
  font-size: 11px;
  font-weight: 700;
  color: var(--color-primary);
  text-transform: uppercase;
  letter-spacing: 2px;
  margin-bottom: var(--space-3);
}

.section-title {
  font-size: 28px;
  font-weight: 800;
  color: var(--color-gray-9);
  margin-bottom: var(--space-4);
  letter-spacing: -0.5px;
  line-height: 1.2;
}

.section-subtitle {
  font-size: 16px;
  color: var(--color-gray-6);
  max-width: 560px;
  margin: 0 auto;
  line-height: 1.65;
}

/* ===== 10. Hero ===== */
.hero {
  background: linear-gradient(135deg, var(--hero-from) 0%, var(--hero-to) 100%);
  color: #fff;
  padding: 72px var(--space-8);
  text-align: center;
}

.hero-content {
  max-width: 720px;
  margin: 0 auto;
}

.hero-badge {
  display: inline-block;
  background: rgba(255,255,255,0.08);
  border: 1px solid rgba(255,255,255,0.18);
  color: rgba(255,255,255,0.75);
  font-size: 11px;
  padding: 5px 16px;
  border-radius: 20px;
  margin-bottom: var(--space-6);
  letter-spacing: 1.5px;
  font-weight: 600;
  text-transform: uppercase;
}

.hero h1 {
  font-size: 44px;
  font-weight: 800;
  margin-bottom: var(--space-5);
  letter-spacing: -1.5px;
  line-height: 1.1;
  color: var(--color-white);
}

.hero p {
  font-size: 17px;
  color: var(--hero-text);
  margin-bottom: var(--space-8);
  line-height: 1.7;
  opacity: 0.85;
  font-weight: 400;
}

.hero-badges {
  display: flex;
  justify-content: center;
  gap: var(--space-2);
  flex-wrap: wrap;
}

.hero-badge-item {
  padding: 6px 14px;
  background: rgba(255,255,255,0.08);
  border: 1px solid rgba(255,255,255,0.15);
  border-radius: 20px;
  font-size: 12px;
  color: rgba(255,255,255,0.8);
  font-weight: 500;
}

/* ===== 11. Page Header ===== */
.page-header {
  background: linear-gradient(135deg, var(--hero-from) 0%, var(--hero-to) 100%);
  color: #fff;
  padding: 52px var(--space-8);
  text-align: center;
  margin: 0 calc(-1 * var(--space-8)) var(--space-8);
  width: calc(100% + var(--space-8) * 2);
}

.page-header h1 {
  font-size: 34px;
  font-weight: 800;
  margin-bottom: var(--space-3);
  color: var(--color-white);
  letter-spacing: -0.8px;
}

.page-header p {
  font-size: 16px;
  color: var(--hero-text);
  opacity: 0.85;
}

/* ===== 12. Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 9px 18px;
  border-radius: var(--radius-md);
  font-size: 13.5px;
  font-weight: 600;
  text-decoration: none;
  transition: background 0.15s, color 0.15s, border-color 0.15s, opacity 0.15s;
  cursor: pointer;
  border: 1px solid transparent;
  line-height: 1;
  white-space: nowrap;
  letter-spacing: 0.1px;
}

.btn:hover {
  text-decoration: none;
  opacity: 0.9;
}

.btn-primary {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
}
.btn-primary:hover {
  background: var(--color-primary-dark);
  border-color: var(--color-primary-dark);
  color: #fff;
  opacity: 1;
}

.btn-secondary {
  background: var(--color-white);
  color: var(--color-gray-9);
  border-color: var(--color-gray-3);
}
.btn-secondary:hover {
  background: var(--color-gray-1);
  border-color: var(--color-gray-4);
  color: var(--color-gray-9);
  opacity: 1;
}

.btn-outline {
  background: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
}
.btn-outline:hover {
  background: var(--color-primary-light);
  color: var(--color-primary);
  opacity: 1;
}

.btn-ghost {
  background: transparent;
  color: var(--color-gray-7);
  border-color: transparent;
}
.btn-ghost:hover {
  background: var(--color-gray-1);
  color: var(--color-gray-9);
  opacity: 1;
}

.btn-white {
  background: #fff;
  color: var(--color-primary);
  border-color: rgba(255,255,255,0.2);
}
.btn-white:hover {
  background: var(--color-primary-light);
  color: var(--color-primary);
  opacity: 1;
}

.btn-sm {
  padding: 6px 12px;
  font-size: 12.5px;
  border-radius: var(--radius-sm);
}

.btn-lg {
  padding: 12px 28px;
  font-size: 15px;
  border-radius: var(--radius-lg);
}

/* ===== 13. Badges / Tags ===== */
.badge {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 20px;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.3px;
  line-height: 1.5;
}

.badge-primary {
  background: var(--color-primary-light);
  color: var(--color-primary);
}
.badge-success {
  background: var(--color-success-bg);
  color: var(--color-success);
}
.badge-warning {
  background: var(--color-warning-bg);
  color: var(--color-warning);
}
.badge-danger {
  background: var(--color-danger-bg);
  color: var(--color-danger);
}
.badge-neutral {
  background: var(--color-gray-1);
  color: var(--color-gray-7);
}

/* ===== 14. Cards（Linear 风格：无阴影，用细边框） ===== */
.card {
  background: var(--color-white);
  border: 1px solid var(--color-gray-3);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  transition: border-color 0.2s, box-shadow 0.2s;
}

.card:hover {
  border-color: var(--color-gray-4);
  box-shadow: var(--shadow-sm);
}

.card-icon {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  margin-bottom: var(--space-4);
}

.card-title {
  font-size: 15px;
  font-weight: 700;
  margin-bottom: var(--space-2);
  color: var(--color-gray-9);
  line-height: 1.3;
  letter-spacing: -0.2px;
}

.card-desc {
  font-size: 13.5px;
  color: var(--color-gray-6);
  line-height: 1.65;
}

/* ===== 15. Alert Boxes ===== */
.alert {
  padding: var(--space-3) var(--space-5);
  border-radius: var(--radius-md);
  border-left: 3px solid;
  font-size: 13.5px;
  line-height: 1.6;
}

.alert-info {
  background: var(--color-info-bg);
  border-color: var(--color-info);
  color: var(--color-info);
}
.alert-success {
  background: var(--color-success-bg);
  border-color: var(--color-success);
  color: var(--color-success);
}
.alert-warning {
  background: var(--color-warning-bg);
  border-color: var(--color-warning);
  color: var(--color-gray-8);
}
.alert-danger {
  background: var(--color-danger-bg);
  border-color: var(--color-danger);
  color: var(--color-danger);
}

/* ===== 16. Article Content ===== */
.article {
  max-width: 100%;
  padding: var(--space-8) var(--space-8) var(--space-12);
  background: var(--color-white);
  border-radius: var(--radius-xl);
  border: 1px solid var(--color-gray-3);
}

.article h1 {
  font-size: 30px;
  font-weight: 800;
  margin-bottom: var(--space-6);
  color: var(--color-gray-9);
  letter-spacing: -0.5px;
  line-height: 1.2;
}

.article h2 {
  font-size: 22px;
  font-weight: 700;
  margin: var(--space-10) 0 var(--space-4);
  color: var(--color-gray-9);
  padding-bottom: var(--space-3);
  border-bottom: 1px solid var(--color-gray-3);
  letter-spacing: -0.3px;
}

.article h3 {
  font-size: 17px;
  font-weight: 700;
  margin: var(--space-8) 0 var(--space-3);
  color: var(--color-gray-9);
  letter-spacing: -0.2px;
}

.article h4 {
  font-size: 14.5px;
  font-weight: 600;
  margin: var(--space-6) 0 var(--space-3);
  color: var(--color-gray-8);
}

.article p {
  margin-bottom: var(--space-4);
  color: var(--color-gray-8);
  line-height: 1.85;
  font-size: 14.5px;
}

.article strong {
  font-weight: 700;
  color: var(--color-gray-9);
}

.article ul,
.article ol {
  margin: var(--space-4) 0;
  padding-left: var(--space-6);
}

.article li {
  margin-bottom: var(--space-2);
  line-height: 1.75;
  font-size: 14px;
  color: var(--color-gray-8);
}

.article table {
  width: 100%;
  border-collapse: collapse;
  margin: var(--space-5) 0;
  font-size: 13.5px;
}

.article th,
.article td {
  padding: var(--space-3) var(--space-4);
  border: 1px solid var(--color-gray-3);
  text-align: left;
}

.article th {
  background: var(--color-gray-1);
  font-weight: 600;
  color: var(--color-gray-9);
}

.article a {
  color: var(--color-primary);
  text-decoration: underline;
  text-underline-offset: 2px;
}

/* ===== 17. Grid Layouts ===== */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-5);
}
.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-5);
}
.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-5);
}

/* ===== 18. Three Pillars Cards（保留渐变，Linear 化） ===== */
.pillars-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-5);
}

/* 3+1 布局：前3个占满一行，第4个居中单独一行 */
.pillars-grid.pillars-grid-3plus1 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-5);
}
.pillars-grid.pillars-grid-3plus1 > :nth-child(4) {
  grid-column: 2 / 3;  /* 居中：起始于第2列 */
  max-width: calc(33.333% - var(--space-5) * 2 / 3); /* 与其他卡片等宽 */
  justify-self: center;
}

.pillars-grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-4);
}

/* ===== 三步验证流程卡片 ===== */
.process-steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-5);
  margin: var(--space-5) 0;
}

.process-step {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-5);
  text-align: center;
  transition: all 0.2s ease;
}

.process-step:hover {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-sm);
}

.process-number {
  width: 48px;
  height: 48px;
  background: var(--color-primary);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  font-weight: 700;
  margin: 0 auto var(--space-3);
}

.process-title {
  font-size: 16px;
  font-weight: 600;
  color: var(--color-heading);
  margin-bottom: var(--space-2);
}

.process-desc {
  font-size: 14px;
  color: var(--color-text);
  line-height: 1.6;
}

.pillar-card {
  padding: var(--space-8);
  border-radius: var(--radius-xl);
  position: relative;
  overflow: hidden;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.pillar-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
}

.pillar-blue {
  background: linear-gradient(145deg, #1e40af 0%, #2563eb 100%);
  color: white;
}
.pillar-green {
  background: linear-gradient(145deg, #166534 0%, #16a34a 100%);
  color: white;
}
.pillar-pink {
  background: linear-gradient(145deg, #9d174d 0%, #db2777 100%);
  color: white;
}

.pillar-icon {
  font-size: 36px;
  margin-bottom: var(--space-4);
  display: block;
}

.pillar-card h3 {
  font-size: 19px;
  font-weight: 700;
  margin-bottom: var(--space-3);
  color: white;
  letter-spacing: -0.3px;
}

.pillar-card p {
  font-size: 13.5px;
  line-height: 1.7;
  opacity: 0.9;
  margin-bottom: var(--space-5);
  color: rgba(255,255,255,0.92);
}

.pillar-link {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  color: white;
  text-decoration: none;
  font-size: 13px;
  font-weight: 600;
  padding: 6px 14px;
  background: rgba(255,255,255,0.15);
  border-radius: 20px;
  border: 1px solid rgba(255,255,255,0.2);
  transition: background 0.15s, opacity 0.15s;
}

.pillar-link:hover {
  background: rgba(255,255,255,0.25);
  opacity: 1;
  color: white;
}

/* ===== 19. Protocol Cards（细边框 + 色条） ===== */
.protocols-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-4);
}

.protocol-card {
  padding: var(--space-5);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-gray-3);
  transition: border-color 0.2s, box-shadow 0.2s;
  position: relative;
}

.protocol-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  border-radius: var(--radius-lg) var(--radius-lg) 0 0;
  transition: height 0.2s;
}

.protocol-card:hover {
  border-color: var(--color-gray-4);
  box-shadow: var(--shadow-sm);
}

.protocol-card:hover::before {
  height: 4px;
}

.proto-icon {
  font-size: 24px;
  margin-bottom: var(--space-3);
  display: block;
}

.proto-title {
  font-size: 14px;
  font-weight: 700;
  margin-bottom: var(--space-2);
  color: var(--color-gray-9);
  letter-spacing: -0.2px;
}

.proto-desc {
  font-size: 12.5px;
  color: var(--color-gray-6);
  line-height: 1.6;
}

.proto-cyan    { background: #f0fdfa; }
.proto-cyan::before    { background: #06b6d4; }
.proto-orange  { background: #fff7ed; }
.proto-orange::before  { background: #ea580c; }
.proto-green   { background: #f0fdf4; }
.proto-green::before   { background: #16a34a; }
.proto-purple  { background: #faf5ff; }
.proto-purple::before  { background: #9333ea; }
.proto-yellow  { background: #fefce8; }
.proto-yellow::before  { background: #ca8a04; }
.proto-indigo  { background: #eef2ff; }
.proto-indigo::before  { background: #4f46e5; }
.proto-rose    { background: #fff1f2; }
.proto-rose::before    { background: #e11d48; }
.proto-emerald { background: #ecfdf5; }
.proto-emerald::before { background: #059669; }

/* ===== 20. Audience Cards（入口分流） ===== */
.audience-section {
  background: linear-gradient(135deg, var(--hero-from) 0%, var(--hero-to) 100%);
  border-radius: var(--radius-xl);
  padding: var(--space-8);
  color: white;
}

.audience-title {
  font-size: 18px;
  font-weight: 700;
  margin: 0 0 var(--space-2);
  color: #f1f5f9;
  letter-spacing: -0.3px;
}

.audience-subtitle {
  font-size: 13px;
  color: var(--hero-muted);
  margin: 0 0 var(--space-6);
  line-height: 1.6;
}

.audience-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-4);
}

.audience-card {
  display: block;
  text-decoration: none;
  background: rgba(255,255,255,0.06);
  border: 1px solid rgba(255,255,255,0.12);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  transition: background 0.15s, border-color 0.15s, opacity 0.15s;
}

.audience-card:hover {
  background: rgba(255,255,255,0.11);
  border-color: rgba(255,255,255,0.25);
  opacity: 1;
  text-decoration: none;
}

.audience-card-icon {
  font-size: 24px;
  margin-bottom: var(--space-3);
  display: block;
}

.audience-card-title {
  font-size: 13.5px;
  font-weight: 700;
  color: #f1f5f9;
  margin-bottom: var(--space-2);
  letter-spacing: -0.1px;
}

.audience-card-desc {
  font-size: 12px;
  color: var(--hero-muted);
  line-height: 1.6;
  margin: 0;
}

.audience-card-link {
  display: block;
  margin-top: var(--space-3);
  font-size: 12px;
  color: #60a5fa;
  font-weight: 600;
}

.audience-footer {
  font-size: 12px;
  color: var(--color-gray-5);
  margin: var(--space-5) 0 0;
  text-align: center;
  opacity: 0.7;
}

/* ===== 21. FAQ Accordion ===== */
.faq-container {
  border: 1px solid var(--color-gray-3);
  border-radius: var(--radius-xl);
  overflow: hidden;
}

.faq-header {
  background: var(--color-white);
  padding: var(--space-5) var(--space-6);
  border-bottom: 1px solid var(--color-gray-3);
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  user-select: none;
  transition: background 0.15s;
}

.faq-header:hover {
  background: var(--color-gray-1);
}

.faq-header-left {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.faq-header-icon {
  font-size: 16px;
}

.faq-header-title {
  font-size: 14.5px;
  font-weight: 700;
  color: var(--color-gray-9);
}

.faq-arrow {
  font-size: 12px;
  color: var(--color-gray-5);
  transition: transform 0.2s;
}

.faq-body {
  padding: var(--space-6);
  display: none;
  background: var(--color-white);
}

.faq-body.open {
  display: block;
}

.faq-items {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.faq-item {
  border-radius: var(--radius-md);
  padding: var(--space-4) var(--space-5);
  border: 1px solid;
}

.faq-item-info {
  background: var(--color-info-bg);
  border-color: var(--color-info-border);
}
.faq-item-success {
  background: var(--color-success-bg);
  border-color: var(--color-success-border);
}
.faq-item-warning {
  background: var(--color-warning-bg);
  border-color: var(--color-warning-border);
}

.faq-item-q {
  font-weight: 700;
  font-size: 13.5px;
  margin: 0 0 var(--space-2);
}

.faq-item-info .faq-item-q    { color: var(--color-info); }
.faq-item-success .faq-item-q { color: var(--color-success); }
.faq-item-warning .faq-item-q { color: var(--color-warning); }

.faq-item-a {
  color: var(--color-gray-7);
  font-size: 13.5px;
  line-height: 1.7;
  margin: 0;
}

/* ===== 22. Quick Link Cards（Linear 风格：无阴影细边框） ===== */
.quick-links-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-5);
}

.quick-link-card {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  text-align: left;
  background: var(--color-white);
  border: 1px solid var(--color-gray-3);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  transition: border-color 0.2s, box-shadow 0.2s;
  cursor: pointer;
  text-decoration: none;
}

.quick-link-card:hover {
  border-color: var(--color-primary-muted);
  box-shadow: var(--shadow-sm);
  opacity: 1;
  text-decoration: none;
}

.quick-link-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--space-4);
  font-size: 24px;
  flex-shrink: 0;
}

.quick-link-title {
  font-size: 15px;
  font-weight: 700;
  color: var(--color-gray-9);
  margin: 0 0 var(--space-2);
  letter-spacing: -0.2px;
}

.quick-link-desc {
  font-size: 13px;
  color: var(--color-gray-6);
  line-height: 1.6;
  flex: 1;
  margin: 0;
}

.quick-link-cta {
  margin-top: var(--space-4);
  font-size: 13px;
  font-weight: 600;
}

/* ===== 23. Architecture Diagram ===== */
.arch-diagram-wrap {
  background: var(--color-gray-1);
  border: 1px solid var(--color-gray-3);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  margin-bottom: var(--space-6);
  overflow-x: auto;
}

.arch-layer-list {
  text-align: left;
  max-width: 680px;
  margin: 0 auto var(--space-6);
  padding: var(--space-4) var(--space-5);
  background: var(--color-gray-1);
  border-radius: var(--radius-md);
  font-size: 13.5px;
}

.arch-layer-list ul {
  margin: var(--space-3) 0 0 0;
  padding-left: var(--space-5);
  color: var(--color-gray-7);
  line-height: 1.9;
}

.arch-layer-list strong {
  color: var(--color-primary);
}

.layer-row {
  display: flex;
  align-items: center;
  margin-bottom: var(--space-4);
  gap: var(--space-4);
}

.layer-label {
  width: 110px;
  font-weight: 700;
  font-size: 13.5px;
  color: var(--color-primary);
  flex-shrink: 0;
}

.layer-bar {
  flex: 1;
  background: var(--color-gray-1);
  padding: var(--space-3) var(--space-5);
  border-radius: var(--radius-md);
  border: 1px solid var(--color-gray-3);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.layer-name {
  font-weight: 600;
  color: var(--color-gray-9);
  font-size: 13.5px;
}

.layer-desc {
  font-size: 12.5px;
  color: var(--color-gray-6);
}

/* ===== 24. Method Box（五层方法论） ===== */
.method-box {
  background: var(--color-gray-1);
  border: 1px solid var(--color-gray-3);
  border-radius: var(--radius-lg);
  padding: var(--space-5) var(--space-6);
  margin: var(--space-6) 0;
}

.method-box-title {
  color: var(--color-gray-9);
  font-size: 14px;
  font-weight: 700;
  margin: 0 0 var(--space-4);
  display: flex;
  align-items: center;
  gap: var(--space-2);
  letter-spacing: -0.2px;
}

.method-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: var(--space-3);
}

.method-item {
  padding: var(--space-3);
  border-radius: var(--radius-md);
  text-align: center;
  transition: transform 0.15s;
}

.method-item:hover {
  transform: translateY(-1px);
}

.method-item-label {
  font-weight: 700;
  margin-bottom: 3px;
  font-size: 12.5px;
  letter-spacing: -0.1px;
}

.method-item-desc {
  font-size: 11px;
  opacity: 0.8;
  font-weight: 500;
}

.method-box-desc {
  color: var(--color-gray-7);
  font-size: 14px;
  margin-bottom: var(--space-3);
  line-height: 1.7;
}

/* 五层方法论颜色变体 */
.method-layer-1 { background: #dbeafe; }
.method-layer-2 { background: #dcfce7; }
.method-layer-3 { background: #fef3c7; }
.method-layer-4 { background: #fce7f3; }
.method-layer-5 { background: #f5f3ff; }

/* Pillar 图标尺寸 */
.pillar-icon {
  font-size: 32px !important;
}

/* Quick link 图标渐变 */
.ql-icon-blue   { background: linear-gradient(135deg, #1e40af 0%, #3b82f6 100%) !important; }
.ql-icon-green  { background: linear-gradient(135deg, #166534 0%, #22c55e 100%) !important; }
.ql-icon-pink   { background: linear-gradient(135deg, #9d174d 0%, #ec4899 100%) !important; }

/* Quick link CTA 颜色 */
.ql-cta-blue   { color: var(--color-primary) !important; }
.ql-cta-green  { color: var(--color-success) !important; }
.ql-cta-pink   { color: #ec4899 !important; }

/* FAQ 内联列表 */
.faq-list {
  margin: var(--space-3) 0 0;
  padding-left: var(--space-5);
  color: var(--color-gray-7);
  font-size: 13.5px;
  line-height: 1.8;
}

.faq-link-note {
  color: var(--color-gray-5);
  font-size: 12.5px;
  margin: var(--space-3) 0 0;
}

/* 第四张 pillar 卡（紫色） */
.pillar-purple {
  background: linear-gradient(145deg, #5b21b6 0%, #7c3aed 100%);
  color: white;
}

/* Article 内联段落 */
.article-intro {
  color: var(--color-gray-7);
  margin-bottom: var(--space-6);
  font-size: 14px;
}

/* 开源链接区 */
.open-source-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  margin: var(--space-4) 0 var(--space-6);
}

.section-intro {
  color: var(--color-gray-6);
  margin-bottom: var(--space-6);
  text-align: center;
}

/* Footer 警告 */
.footer-warning {
  color: var(--color-gray-5);
  font-size: 13px;
  margin-bottom: var(--space-3);
  text-align: center;
}

/* ===== 25. Message Wall ===== */
.message-form {
  background: var(--color-white);
  border: 1px solid var(--color-gray-3);
  border-radius: var(--radius-xl);
  padding: var(--space-8);
  margin-bottom: var(--space-10);
}

.form-group {
  margin-bottom: var(--space-5);
}

.form-group label {
  display: block;
  font-weight: 600;
  font-size: 13.5px;
  margin-bottom: var(--space-2);
  color: var(--color-gray-9);
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 10px 14px;
  border: 1px solid var(--color-gray-3);
  border-radius: var(--radius-md);
  font-size: 13.5px;
  font-family: inherit;
  color: var(--color-gray-9);
  background: var(--color-white);
  transition: border-color 0.15s, box-shadow 0.15s;
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(37,99,235,0.08);
}

.form-group textarea {
  min-height: 100px;
  resize: vertical;
}

.form-note {
  font-size: 12px;
  color: var(--color-gray-5);
  margin-top: var(--space-2);
}

.message-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-5);
}

.message-item {
  background: var(--color-white);
  border: 1px solid var(--color-gray-3);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  transition: border-color 0.15s, box-shadow 0.15s;
}

.message-item:hover {
  border-color: var(--color-gray-4);
  box-shadow: var(--shadow-xs);
}

.message-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-3);
}

.message-author {
  font-weight: 700;
  font-size: 13.5px;
  color: var(--color-primary);
}

.message-time {
  font-size: 12px;
  color: var(--color-gray-5);
}

.message-location {
  font-size: 11px;
  color: var(--color-gray-6);
  background: var(--color-gray-1);
  padding: 3px 8px;
  border-radius: 4px;
}

.message-content {
  color: var(--color-gray-8);
  line-height: 1.7;
  font-size: 14px;
}

.message-status {
  display: inline-block;
  font-size: 11px;
  padding: 2px 8px;
  border-radius: 4px;
  margin-left: var(--space-2);
  font-weight: 600;
}

.message-status.pending {
  background: var(--color-warning-bg);
  color: var(--color-warning);
}
.message-status.approved {
  background: var(--color-success-bg);
  color: var(--color-success);
}

/* ===== 26. Page Nav ===== */
.page-nav {
  max-width: 1120px;
  margin: 0 auto;
  padding: var(--space-6) var(--space-8);
  display: flex;
  justify-content: space-between;
  gap: var(--space-5);
}

.page-nav a {
  flex: 1;
  background: var(--color-white);
  border: 1px solid var(--color-gray-3);
  border-radius: var(--radius-lg);
  padding: var(--space-4) var(--space-5);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: var(--space-3);
  transition: border-color 0.15s, background 0.15s;
}

.page-nav a:hover {
  border-color: var(--color-primary-muted);
  background: var(--color-primary-light);
  opacity: 1;
  text-decoration: none;
}

.page-nav a:last-child {
  justify-content: flex-end;
}

.page-nav .nav-label {
  font-size: 11px;
  color: var(--color-primary);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.page-nav .nav-title {
  font-size: 13.5px;
  font-weight: 600;
  color: var(--color-gray-9);
}

/* ===== 27. Footer ===== */
.footer {
  background: #0f172a;
  color: var(--color-gray-5);
  padding: 56px var(--space-8) 40px;
  margin-top: 80px;
}

.footer-inner {
  max-width: 1280px;
  margin: 0 auto;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--space-10);
  margin-bottom: var(--space-10);
}

.footer-brand-name {
  font-size: 16px;
  font-weight: 700;
  color: #fff;
  margin-bottom: var(--space-3);
}

.footer-brand-desc {
  font-size: 13px;
  line-height: 1.7;
  color: var(--color-gray-5);
  opacity: 0.8;
}

.footer-title {
  font-size: 12px;
  font-weight: 700;
  color: #fff;
  margin-bottom: var(--space-4);
  text-transform: uppercase;
  letter-spacing: 0.8px;
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.footer-links a {
  color: var(--color-gray-5);
  text-decoration: none;
  font-size: 13.5px;
  transition: color 0.15s;
  opacity: 0.8;
}

.footer-links a:hover {
  color: #fff;
  opacity: 1;
  text-decoration: none;
}

.footer-bottom {
  border-top: 1px solid #1e293b;
  padding-top: var(--space-6);
  text-align: center;
  font-size: 12.5px;
  color: var(--color-gray-6);
  line-height: 1.8;
}

.footer-bottom p {
  margin-bottom: var(--space-2);
}

/* ===== 28. Utility Classes ===== */
.text-center  { text-align: center; }
.text-right   { text-align: right; }
.text-muted   { color: var(--color-gray-6); font-size: 13px; }
.text-primary { color: var(--color-primary); }
.text-success { color: var(--color-success); }
.text-warning { color: var(--color-warning); }
.text-danger  { color: var(--color-danger); }

.bg-light { background: var(--color-gray-1); }
.bg-white { background: var(--color-white); }

.mt-0  { margin-top: 0; }
.mt-4  { margin-top: var(--space-1); }
.mt-5  { margin-top: 20px; }
.mt-6  { margin-top: var(--space-6); }
.mt-8  { margin-top: var(--space-2); }
.mt-12 { margin-top: var(--space-3); }
.mt-16 { margin-top: var(--space-4); }
.mt-24 { margin-top: var(--space-6); }
.mt-32 { margin-top: var(--space-8); }
.mt-48 { margin-top: var(--space-12); }

.mb-0  { margin-bottom: 0; }
.mb-8  { margin-bottom: var(--space-2); }
.mb-12 { margin-bottom: var(--space-3); }
.mb-16 { margin-bottom: var(--space-4); }
.mb-24 { margin-bottom: var(--space-6); }
.mb-32 { margin-bottom: var(--space-8); }

.mr-3  { margin-right: var(--space-3); }

.pt-0  { padding-top: 0; }
.pb-0  { padding-bottom: 0; }

.w-full { width: 100%; }
.hidden { display: none; }

/* ===== 29. Responsive ===== */
@media (max-width: 1024px) {
  .grid-4,
  .protocols-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-8);
  }

  .footer-grid > div:first-child {
    grid-column: 1 / -1;
  }
}

@media (max-width: 768px) {
  .header-inner {
    padding: 0 var(--space-4);
  }

  .nav {
    display: none;
  }

  .main-container {
    padding: 0 var(--space-5);
  }

  .hero {
    padding: 48px var(--space-5);
  }

  .hero h1 {
    font-size: 32px;
  }

  .hero p {
    font-size: 15px;
  }

  .page-header {
    padding: 36px var(--space-5);
    margin: 0 calc(-1 * var(--space-5)) var(--space-6);
    width: calc(100% + var(--space-5) * 2);
  }

  .section {
    padding: var(--space-8) 0;
  }

  .section-title {
    font-size: 24px;
  }

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

  .pillars-grid,
  .audience-grid,
  .quick-links-grid {
    grid-template-columns: 1fr;
  }

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

  .protocols-grid {
    grid-template-columns: 1fr;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: var(--space-6);
  }

  .footer {
    padding: var(--space-8) var(--space-5) var(--space-8);
  }

  .article {
    padding: var(--space-5) var(--space-5) var(--space-8);
    border-radius: var(--radius-lg);
  }

  .layer-row {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-2);
  }

  .layer-label {
    width: auto;
  }

  .page-nav {
    flex-direction: column;
    padding: var(--space-4) var(--space-5);
    gap: var(--space-3);
  }

  .page-nav a:last-child {
    justify-content: flex-start;
  }
}

@media (max-width: 480px) {
  .hero h1 {
    font-size: 26px;
  }

  .method-grid {
    grid-template-columns: 1fr;
  }

  .hero-badges {
    gap: var(--space-2);
  }
}