/* ==========================================================================
   NiceDuck (niceduckvpn.sbs) — SWISS INTERNATIONAL GRID // BAUHAUS CONSTRUCTIVIST
   美学范式：瑞士国际主义网格 · 鲍豪斯几何构成派 (Museum Architectural Grid System)
   色彩体系：建筑米灰 #F4F3EF · 纯白构成面 #FFFFFF · 碳黑对比体 #111111
             国际主义朱红橙 #FF3B00 · 构成派钴蓝 #0047AB · 鲍豪斯赭黄 #E5A000
   结构特征：0px 锐利直角 · 1.5px 裸露建筑网格线 · 4px 硬朗几何投影 · 左轨非对称排版
   ========================================================================== */

:root {
  --font-sans: "Helvetica Neue", Helvetica, "Inter", -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  --font-mono: "JetBrains Mono", "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;

  /* Swiss International / Bauhaus Constructivist Color Palette */
  --bg-offwhite: #F4F3EF;            /* Museum Architectural Off-White background */
  --surface-white: #FFFFFF;          /* Pure Constructivist White surface */
  --surface-black: #111111;          /* Stark Carbon Black contrast surface */
  --ink-black: #111111;              /* High-Contrast Typographic Black ink */
  --ink-muted: #4A4A46;              /* Architectural Concrete Gray muted text */
  --accent-vermilion: #FF3B00;       /* Bauhaus International Vermilion-Orange primary accent */
  --accent-vermilion-hover: #D93200; /* Primary hover */
  --accent-cobalt: #0047AB;          /* Constructivist Cobalt Blue secondary accent */
  --accent-ochre: #E5A000;           /* Bauhaus Primary Ochre Yellow accent */
  --grid-border: 1.5px solid #111111;/* Exposed structural architectural grid lines */
  --grid-border-heavy: 2.5px solid #111111;
  --shadow-swiss: 4px 4px 0 #111111;
  --shadow-swiss-lg: 6px 6px 0 #111111;
  --shadow-vermilion: 4px 4px 0 #FF3B00;

  /* Legacy alias mappings for subpages */
  --color-paper: #F4F3EF;
  --color-paper-card: #FFFFFF;
  --color-paper-warm: #EAE8E1;
  --color-ink-deep: #111111;
  --color-ink-body: #111111;
  --color-ink-muted: #4A4A46;
  --color-cinnabar: #FF3B00;
  --color-cinnabar-hover: #D93200;
  --color-gold: #0047AB;
  --color-pine: #0047AB;
  --color-cyan: #0047AB;
  --color-line: #111111;
  --color-line-dark: #111111;

  --max-width-site: 1240px;
  --max-width-read: 880px;
  --radius-seal: 0px;
}

/* Base Reset */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  border-radius: 0 !important;
}

html {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.65;
  color: var(--ink-black);
  background-color: var(--bg-offwhite);
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background-color: var(--bg-offwhite);
  background-image:
    linear-gradient(to right, rgba(17, 17, 17, 0.05) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(17, 17, 17, 0.05) 1px, transparent 1px);
  background-size: 40px 40px;
}

a {
  color: var(--ink-black);
  text-decoration: underline;
  text-decoration-thickness: 1.5px;
  text-underline-offset: 3px;
  transition: color 0.15s ease, background-color 0.15s ease;
}

a:hover {
  color: var(--accent-vermilion);
}

/* Skip Link (Accessibility) */
.skip-link {
  position: absolute;
  top: -80px;
  left: 1.5rem;
  background: var(--accent-vermilion);
  color: var(--surface-white);
  padding: 0.75rem 1.25rem;
  font-family: var(--font-mono);
  font-weight: 800;
  font-size: 0.85rem;
  border: var(--grid-border);
  box-shadow: var(--shadow-swiss);
  z-index: 1000;
  text-decoration: none;
  text-transform: uppercase;
}

.skip-link:focus {
  top: 1rem;
}

:focus-visible {
  outline: 2.5px solid var(--accent-vermilion);
  outline-offset: 2px;
}

/* Containers */
.container {
  width: 100%;
  max-width: var(--max-width-site);
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.5rem;
  padding-right: 1.5rem;
}

.read-container {
  width: 100%;
  max-width: var(--max-width-read);
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.5rem;
  padding-right: 1.5rem;
}

/* Bauhaus Constructivist Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-family: var(--font-sans);
  font-size: 0.95rem;
  font-weight: 800;
  padding: 0.8rem 1.75rem;
  min-height: 48px;
  min-width: 44px;
  border: var(--grid-border);
  cursor: pointer;
  text-decoration: none;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  transition: transform 0.12s ease, background-color 0.12s ease, box-shadow 0.12s ease, color 0.12s ease;
}

.btn:active {
  transform: translate(2px, 2px);
  box-shadow: 2px 2px 0 #111111 !important;
}

.btn-seal-primary {
  background-color: var(--accent-vermilion);
  color: var(--surface-white);
  border: var(--grid-border);
  box-shadow: var(--shadow-swiss);
}

.btn-seal-primary:hover {
  background-color: var(--accent-vermilion-hover);
  color: var(--surface-white);
  transform: translate(-1px, -1px);
  box-shadow: var(--shadow-swiss-lg);
  text-decoration: none;
}

.btn-seal-secondary {
  background-color: var(--surface-white);
  color: var(--ink-black);
  border: var(--grid-border);
  box-shadow: var(--shadow-swiss);
}

.btn-seal-secondary:hover {
  background-color: var(--accent-ochre);
  color: var(--ink-black);
  transform: translate(-1px, -1px);
  box-shadow: var(--shadow-swiss-lg);
  text-decoration: none;
}

/* ==========================================================================
   Header — Swiss Architectural Top Bar
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--surface-white);
  border-bottom: var(--grid-border-heavy);
}

.header-inner {
  display: flex;
  align-items: stretch;
  justify-content: space-between;
  min-height: 70px;
}

.brand-stamp {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 1.25rem;
  font-weight: 900;
  color: var(--ink-black);
  text-decoration: none;
  letter-spacing: -0.02em;
  padding-right: 1.25rem;
}

.brand-stamp:hover {
  color: var(--ink-black);
}

.stamp-box {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  background-color: var(--accent-vermilion);
  color: var(--surface-white);
  font-family: var(--font-mono);
  font-weight: 900;
  font-size: 0.95rem;
  border: var(--grid-border);
  box-shadow: 2px 2px 0 #111111;
  position: relative;
}

.stamp-box::after {
  content: "";
  position: absolute;
  bottom: 3px;
  right: 3px;
  width: 6px;
  height: 6px;
  background-color: var(--accent-ochre);
}

.brand-sub {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--surface-white);
  background-color: var(--ink-black);
  font-weight: 700;
  padding: 0.2rem 0.5rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.nav-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  align-self: center;
  padding: 0.5rem 0.95rem;
  min-height: 44px;
  min-width: 44px;
  background: var(--surface-white);
  border: var(--grid-border);
  box-shadow: 2px 2px 0 #111111;
  color: var(--ink-black);
  font-family: var(--font-mono);
  font-size: 0.88rem;
  font-weight: 800;
  cursor: pointer;
  text-transform: uppercase;
}

.site-nav {
  display: none;
}

.site-nav.is-open {
  display: flex;
  flex-direction: column;
  position: absolute;
  top: 70px;
  left: 0;
  right: 0;
  background-color: var(--surface-white);
  border-bottom: var(--grid-border-heavy);
  padding: 1.5rem;
  box-shadow: 0 8px 0 #111111;
}

.nav-menu {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.nav-link {
  color: var(--ink-black);
  font-weight: 800;
  font-size: 0.95rem;
  text-decoration: none;
  letter-spacing: 0.02em;
  padding: 0.35rem 0.5rem;
  border-left: 3px solid transparent;
}

.nav-link:hover,
.nav-link[aria-current="page"] {
  color: var(--accent-vermilion);
  border-left-color: var(--accent-vermilion);
  background-color: var(--bg-offwhite);
  text-decoration: none;
}

.nav-cta {
  width: 100%;
}

/* ==========================================================================
   Hero Section — Swiss Constructivist Exhibition Catalog Header
   ========================================================================== */
.hero-section {
  padding: 3.5rem 0 4rem;
  border-bottom: var(--grid-border-heavy);
  background-color: var(--bg-offwhite);
  position: relative;
}

.hero-swiss-frame {
  border: var(--grid-border-heavy);
  background-color: var(--surface-white);
  box-shadow: var(--shadow-swiss-lg);
  margin-bottom: 2.5rem;
}

.hero-top-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  padding: 0.65rem 1.25rem;
  background-color: var(--surface-black);
  color: var(--surface-white);
  border-bottom: var(--grid-border);
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  gap: 0.5rem;
}

.hero-color-dots {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
}

.bauhaus-dot {
  width: 12px;
  height: 12px;
  display: inline-block;
  border: 1px solid var(--surface-white);
}

.bauhaus-dot--red { background-color: var(--accent-vermilion); }
.bauhaus-dot--blue { background-color: var(--accent-cobalt); }
.bauhaus-dot--yellow { background-color: var(--accent-ochre); }

.hero-proclamation {
  padding: 2.5rem 2rem;
  text-align: left;
  position: relative;
  border-bottom: var(--grid-border);
  background:
    linear-gradient(135deg, transparent 92%, var(--accent-ochre) 92%);
}

.hero-seal-tag {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.35rem 0.85rem;
  background-color: var(--accent-cobalt);
  border: var(--grid-border);
  box-shadow: 2px 2px 0 #111111;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  font-weight: 800;
  color: var(--surface-white);
  margin-bottom: 1.25rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.hero-proclamation h1 {
  font-size: 2.35rem;
  font-weight: 900;
  color: var(--ink-black);
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin-bottom: 1.25rem;
  max-width: 880px;
}

.hero-proclamation .lead-sub {
  font-size: 1.12rem;
  color: var(--ink-muted);
  line-height: 1.7;
  margin-bottom: 2rem;
  max-width: 760px;
  border-left: 4px solid var(--accent-vermilion);
  padding-left: 1rem;
}

.hero-actions-center {
  display: flex;
  justify-content: flex-start;
  flex-wrap: wrap;
  gap: 1rem;
}

/* Interactive Bauhaus Protocol / Node Matrix Deck */
.astrolabe-deck {
  background-color: var(--surface-white);
  border: var(--grid-border-heavy);
  box-shadow: var(--shadow-swiss-lg);
  padding: 0;
  max-width: 100%;
  margin: 0 auto;
}

.astrolabe-deck-header {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  background-color: var(--bg-offwhite);
  border-bottom: var(--grid-border);
  padding: 1rem 1.5rem;
  gap: 1rem;
}

.deck-title {
  font-family: var(--font-mono);
  font-size: 0.98rem;
  font-weight: 900;
  color: var(--ink-black);
  display: flex;
  align-items: center;
  gap: 0.65rem;
  letter-spacing: 0.03em;
}

.deck-mode-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.mode-tab-btn {
  background: var(--surface-white);
  border: var(--grid-border);
  box-shadow: 2px 2px 0 #111111;
  padding: 0.45rem 0.95rem;
  font-family: var(--font-mono);
  font-size: 0.84rem;
  font-weight: 800;
  color: var(--ink-black);
  cursor: pointer;
  transition: all 0.15s ease;
}

.mode-tab-btn:hover {
  background: var(--accent-ochre);
  color: var(--ink-black);
}

.mode-tab-btn.is-active {
  background: var(--accent-vermilion);
  color: var(--surface-white);
  transform: translate(1px, 1px);
  box-shadow: 1px 1px 0 #111111;
}

.astrolabe-grid {
  display: grid;
  grid-template-columns: 1fr;
}

.astrolabe-visual-box {
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 1.75rem;
  background-color: var(--bg-offwhite);
  border-bottom: var(--grid-border);
}

.astrolabe-visual-box img,
.astrolabe-visual-box svg {
  width: 100%;
  max-width: 460px;
  height: auto;
  border: var(--grid-border);
  box-shadow: var(--shadow-swiss);
  background-color: var(--bg-offwhite);
}

.astrolabe-telemetry {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  padding: 1.75rem;
  gap: 1.5rem;
  background-color: var(--surface-white);
}

.telemetry-route-box {
  background-color: var(--bg-offwhite);
  border: var(--grid-border);
  border-left: 6px solid var(--accent-vermilion);
  box-shadow: var(--shadow-swiss);
  padding: 1.35rem;
}

.route-heading {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--accent-cobalt);
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 0.45rem;
}

.route-desc {
  font-size: 1.05rem;
  font-weight: 800;
  color: var(--ink-black);
  margin-bottom: 0.5rem;
}

.route-stats {
  font-family: var(--font-mono);
  font-size: 0.86rem;
  color: var(--ink-muted);
  font-weight: 600;
}

.telemetry-spec-bar {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border: var(--grid-border);
  background-color: var(--surface-black);
  color: var(--surface-white);
}

.spec-cell {
  padding: 0.75rem;
  border-right: 1px solid #333333;
}

.spec-cell:last-child {
  border-right: none;
}

.spec-cell-label {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--accent-ochre);
  display: block;
}

.spec-cell-val {
  font-family: var(--font-mono);
  font-size: 0.95rem;
  font-weight: 800;
}

.client-support-rack {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.client-chip {
  background-color: var(--surface-white);
  border: var(--grid-border);
  box-shadow: 2px 2px 0 #111111;
  padding: 0.35rem 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--ink-black);
}

/* ==========================================================================
   Asymmetric Left-Rail Swiss Section Headers
   ========================================================================== */
.section-banner {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.75rem;
  margin-bottom: 2.5rem;
  padding-bottom: 1.25rem;
  border-bottom: var(--grid-border-heavy);
  text-align: left;
}

.section-seal {
  display: inline-flex;
  align-items: center;
  align-self: flex-start;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  font-weight: 900;
  color: var(--surface-white);
  background-color: var(--ink-black);
  padding: 0.3rem 0.75rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  border: var(--grid-border);
  box-shadow: 3px 3px 0 var(--accent-vermilion);
}

.section-banner h2 {
  font-size: 1.95rem;
  font-weight: 900;
  color: var(--ink-black);
  line-height: 1.25;
  letter-spacing: -0.02em;
}

.section-banner p {
  font-size: 1.02rem;
  color: var(--ink-muted);
  max-width: 680px;
}

/* ==========================================================================
   GRID 01 // 核心架构四象限 (Features - 4 Constructivist Spec Cells)
   ========================================================================== */
.features-section {
  padding: 4.5rem 0;
  border-bottom: var(--grid-border-heavy);
  background-color: var(--surface-white);
}

.features-matrix {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

.feature-pillar {
  background-color: var(--bg-offwhite);
  border: var(--grid-border);
  box-shadow: var(--shadow-swiss);
  padding: 2rem 1.65rem;
  position: relative;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
  display: flex;
  flex-direction: column;
}

.feature-pillar:hover {
  transform: translate(-2px, -2px);
  box-shadow: var(--shadow-swiss-lg);
  background-color: var(--surface-white);
}

.pillar-corner-mark {
  font-family: var(--font-mono);
  font-size: 2.25rem;
  font-weight: 900;
  line-height: 1;
  color: var(--accent-vermilion);
  margin-bottom: 0.75rem;
  display: block;
}

.feature-pillar:nth-child(2) .pillar-corner-mark {
  color: var(--accent-cobalt);
}

.feature-pillar:nth-child(3) .pillar-corner-mark {
  color: var(--accent-ochre);
  -webkit-text-stroke: 1px #111111;
}

.feature-pillar:nth-child(4) .pillar-corner-mark {
  color: var(--ink-black);
}

.pillar-sign {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 800;
  color: var(--surface-white);
  background-color: var(--ink-black);
  padding: 0.2rem 0.55rem;
  margin-bottom: 0.85rem;
  align-self: flex-start;
  letter-spacing: 0.06em;
}

.feature-pillar h3 {
  font-size: 1.25rem;
  font-weight: 900;
  color: var(--ink-black);
  margin-bottom: 0.65rem;
}

.feature-pillar p {
  font-size: 0.94rem;
  line-height: 1.65;
  color: var(--ink-muted);
  margin-bottom: 0;
}

/* ==========================================================================
   GRID 02 // 真实场景三维投射 (Use Cases - 3 Blueprints)
   ========================================================================== */
.usecases-section {
  padding: 4.5rem 0;
  background-color: var(--bg-offwhite);
  border-bottom: var(--grid-border-heavy);
}

.usecases-scroll {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

.usecase-tome {
  background-color: var(--surface-white);
  border: var(--grid-border);
  border-top: 6px solid var(--accent-cobalt);
  box-shadow: var(--shadow-swiss);
  padding: 2rem 1.75rem;
  position: relative;
}

.usecase-tome:nth-child(2) {
  border-top-color: var(--accent-vermilion);
}

.usecase-tome:nth-child(3) {
  border-top-color: var(--accent-ochre);
}

.tome-period {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 800;
  color: var(--accent-vermilion);
  margin-bottom: 0.45rem;
  letter-spacing: 0.05em;
}

.usecase-tome h3 {
  font-size: 1.32rem;
  font-weight: 900;
  color: var(--ink-black);
  margin-bottom: 0.5rem;
}

.tome-device {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--surface-white);
  background-color: var(--accent-cobalt);
  padding: 0.2rem 0.6rem;
  margin-bottom: 1rem;
}

.usecase-tome p {
  font-size: 0.95rem;
  line-height: 1.68;
  color: var(--ink-muted);
  margin-bottom: 0;
}

/* ==========================================================================
   GRID 03 // 标准化订阅模组 (Pricing - 3 Modules)
   ========================================================================== */
.pricing-section {
  padding: 4.5rem 0;
  background-color: var(--surface-white);
  border-bottom: var(--grid-border-heavy);
}

.pricing-plaque-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
  max-width: 1120px;
  margin: 0 auto;
}

.pricing-plaque {
  background-color: var(--bg-offwhite);
  border: var(--grid-border-heavy);
  box-shadow: var(--shadow-swiss);
  padding: 2.25rem 1.85rem;
  display: flex;
  flex-direction: column;
  position: relative;
}

.pricing-plaque--recommend {
  background-color: var(--surface-white);
  border: 2.5px solid var(--ink-black);
  box-shadow: 6px 6px 0 var(--accent-vermilion);
}

.wax-seal-badge {
  position: absolute;
  top: -15px;
  right: 1.25rem;
  background-color: var(--accent-vermilion);
  color: var(--surface-white);
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 900;
  padding: 0.3rem 0.85rem;
  border: var(--grid-border);
  box-shadow: 2px 2px 0 #111111;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.plaque-head {
  border-bottom: var(--grid-border);
  padding-bottom: 1.25rem;
  margin-bottom: 1.25rem;
}

.plaque-head h3 {
  font-size: 1.4rem;
  font-weight: 900;
  color: var(--ink-black);
  margin-bottom: 0.3rem;
}

.plaque-role {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--ink-muted);
  font-weight: 700;
  margin-bottom: 0.9rem;
}

.plaque-price {
  font-family: var(--font-mono);
  font-size: 2.6rem;
  font-weight: 900;
  color: var(--ink-black);
  display: flex;
  align-items: baseline;
  gap: 0.35rem;
}

.plaque-price span {
  font-family: var(--font-sans);
  font-size: 0.92rem;
  font-weight: 700;
  color: var(--ink-muted);
}

.plaque-checklist {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
  margin-bottom: 2rem;
  flex-grow: 1;
}

.plaque-item {
  display: flex;
  align-items: flex-start;
  gap: 0.65rem;
  font-size: 0.94rem;
  font-weight: 600;
  color: var(--ink-black);
  padding-bottom: 0.65rem;
  border-bottom: 1px dashed rgba(17, 17, 17, 0.2);
}

.plaque-item:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.seal-check-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 20px;
  height: 20px;
  background-color: var(--ink-black);
  color: var(--accent-ochre);
  font-family: var(--font-mono);
  font-weight: 900;
  flex-shrink: 0;
  font-size: 0.75rem;
  margin-top: 2px;
}

.pricing-plaque--recommend .seal-check-mark {
  background-color: var(--accent-vermilion);
  color: var(--surface-white);
}

.plaque-cta {
  width: 100%;
}

/* ==========================================================================
   GRID 04 // 全球流媒体传输矩阵 (Streaming - 6 Cells)
   ========================================================================== */
.streaming-section {
  padding: 4.5rem 0;
  background-color: var(--bg-offwhite);
  border-bottom: var(--grid-border-heavy);
}

.streaming-scroll-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
}

.streaming-tile {
  background-color: var(--surface-white);
  border: var(--grid-border);
  box-shadow: var(--shadow-swiss);
  padding: 1.35rem;
  display: flex;
  align-items: center;
  gap: 1.1rem;
  transition: transform 0.15s ease;
}

.streaming-tile:hover {
  transform: translate(-2px, -2px);
  box-shadow: var(--shadow-swiss-lg);
}

.tile-stamp-icon {
  width: 46px;
  height: 46px;
  background-color: var(--accent-vermilion);
  border: var(--grid-border);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--surface-white);
  flex-shrink: 0;
}

.streaming-tile:nth-child(even) .tile-stamp-icon {
  background-color: var(--accent-cobalt);
}

.streaming-tile:nth-child(3n) .tile-stamp-icon {
  background-color: var(--accent-ochre);
  color: var(--ink-black);
}

.tile-info h3 {
  font-family: var(--font-mono);
  font-size: 1.02rem;
  font-weight: 900;
  color: var(--ink-black);
  margin-bottom: 0.25rem;
}

.tile-info span {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--ink-muted);
  display: block;
}

/* ==========================================================================
   GRID 05 // 智能算力接口阵列 (AI Tools - 6 Cells)
   ========================================================================== */
.ai-section {
  padding: 4.5rem 0;
  background-color: var(--surface-white);
  border-bottom: var(--grid-border-heavy);
}

.ai-atelier-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
}

.ai-atelier-card {
  background-color: var(--bg-offwhite);
  border: var(--grid-border);
  box-shadow: var(--shadow-swiss);
  padding: 1.65rem;
  position: relative;
}

.ai-card-top {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  margin-bottom: 0.75rem;
  padding-bottom: 0.65rem;
  border-bottom: var(--grid-border);
}

.ai-card-top h3 {
  font-family: var(--font-mono);
  font-size: 1.02rem;
  font-weight: 900;
  color: var(--ink-black);
}

.ai-colophon-tag {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 800;
  color: var(--ink-black);
  background-color: var(--accent-ochre);
  border: 1px solid #111111;
  padding: 0.15rem 0.5rem;
  text-transform: uppercase;
}

.ai-atelier-card p {
  font-size: 0.92rem;
  line-height: 1.65;
  color: var(--ink-muted);
  margin-bottom: 0;
}

/* ==========================================================================
   GRID 06 // 技术释疑索引表 (FAQ - 6 Items)
   ========================================================================== */
.faq-section {
  padding: 4.5rem 0;
  background-color: var(--bg-offwhite);
  border-bottom: var(--grid-border-heavy);
}

.faq-record-deck {
  max-width: 920px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.faq-item details {
  border: var(--grid-border);
  background-color: var(--surface-white);
  box-shadow: var(--shadow-swiss);
}

.faq-item summary {
  padding: 1.25rem 1.5rem;
  font-size: 1.05rem;
  font-weight: 800;
  color: var(--ink-black);
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  user-select: none;
  gap: 1rem;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::after {
  content: "[ + ]";
  font-family: var(--font-mono);
  font-size: 0.88rem;
  font-weight: 900;
  color: var(--surface-white);
  background-color: var(--ink-black);
  padding: 0.2rem 0.55rem;
  flex-shrink: 0;
}

.faq-item details[open] summary {
  background-color: var(--ink-black);
  color: var(--surface-white);
}

.faq-item details[open] summary::after {
  content: "[ - ]";
  background-color: var(--accent-vermilion);
  color: var(--surface-white);
}

.faq-answer {
  padding: 1.35rem 1.5rem;
  font-size: 0.96rem;
  color: var(--ink-black);
  line-height: 1.75;
  border-top: var(--grid-border);
  background-color: var(--surface-white);
}

/* ==========================================================================
   GRID 07 // 终端接入指令台 (Final CTA Block)
   ========================================================================== */
.final-cta-section {
  padding: 4.5rem 0;
  background-color: var(--surface-white);
  border-bottom: var(--grid-border-heavy);
}

.final-cta-scroll {
  background-color: var(--surface-black);
  color: var(--surface-white);
  border: var(--grid-border-heavy);
  box-shadow: 8px 8px 0 var(--accent-vermilion);
  padding: 3.5rem 2rem;
  text-align: left;
  max-width: 920px;
  margin: 0 auto;
  position: relative;
}

.final-cta-scroll h2 {
  font-size: 2rem;
  font-weight: 900;
  color: var(--surface-white);
  margin-bottom: 0.85rem;
  letter-spacing: -0.02em;
}

.final-cta-scroll p {
  font-size: 1.08rem;
  color: #D6D5D0;
  margin-bottom: 2rem;
  max-width: 660px;
}

/* ==========================================================================
   Footer — Swiss Catalog Colophon
   ========================================================================== */
.site-footer {
  margin-top: auto;
  background-color: var(--bg-offwhite);
  border-top: var(--grid-border-heavy);
  padding: 3rem 0 2.5rem;
  font-size: 0.9rem;
  color: var(--ink-muted);
}

.footer-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 1.25rem;
  justify-content: center;
  margin-bottom: 1.5rem;
}

.footer-link {
  font-family: var(--font-mono);
  color: var(--ink-black);
  font-weight: 800;
  font-size: 0.88rem;
  padding: 0.25rem 0.6rem;
  border: 1px solid var(--ink-black);
  background-color: var(--surface-white);
  text-decoration: none;
  box-shadow: 2px 2px 0 #111111;
}

.footer-link:hover {
  background-color: var(--accent-vermilion);
  color: var(--surface-white);
}

.footer-disclosure {
  text-align: center;
  font-size: 0.84rem;
  color: var(--ink-muted);
  margin-bottom: 0.65rem;
}

.footer-copyright {
  text-align: center;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--ink-black);
}

/* Mobile Floating CTA Bar */
.mobile-float-cta {
  display: none;
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  z-index: 90;
  background-color: var(--surface-white);
  border-top: var(--grid-border-heavy);
  padding: 0.75rem 1.25rem;
  box-shadow: 0 -4px 0 #111111;
  align-items: center;
  justify-content: space-between;
  transform: translateY(100%);
  transition: transform 0.25s ease-out;
}

.mobile-float-cta.is-visible {
  display: flex;
  transform: translateY(0);
}

.float-cta-info {
  display: flex;
  flex-direction: column;
}

.float-cta-title {
  font-size: 0.9rem;
  font-weight: 900;
  color: var(--ink-black);
}

.float-cta-desc {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  color: var(--accent-cobalt);
  font-weight: 700;
}

.float-cta-btn {
  padding: 0.55rem 1.15rem;
  font-size: 0.88rem;
  min-height: 42px;
}

/* ==========================================================================
   Subpages: Breadcrumbs, Guides Hub (jiaocheng.html), Articles & Legal Pages
   ========================================================================== */
.breadcrumb-nav {
  padding: 0.85rem 0;
  border-bottom: var(--grid-border);
  background-color: var(--bg-offwhite);
  font-family: var(--font-mono);
  font-size: 0.84rem;
  font-weight: 700;
}

.breadcrumb-list {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.55rem;
  color: var(--ink-muted);
}

.breadcrumb-separator {
  color: var(--accent-vermilion);
  font-weight: 900;
  user-select: none;
}

/* Guides Hub (jiaocheng.html) */
.guides-hero {
  padding: 3rem 0 2.25rem;
  background-color: var(--surface-white);
  border-bottom: var(--grid-border-heavy);
}

.guides-hero h1 {
  font-size: 2.2rem;
  font-weight: 900;
  color: var(--ink-black);
  margin-bottom: 0.65rem;
  letter-spacing: -0.02em;
}

.guides-grid {
  padding: 3.25rem 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.85rem;
}

.guide-card {
  background-color: var(--surface-white);
  border: var(--grid-border);
  box-shadow: var(--shadow-swiss);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.guide-card:hover {
  transform: translate(-2px, -2px);
  box-shadow: var(--shadow-swiss-lg);
}

.guide-card-media {
  width: 100%;
  aspect-ratio: 16 / 10;
  background-color: var(--bg-offwhite);
  border-bottom: var(--grid-border);
  display: flex;
  align-items: center;
  justify-content: center;
}

.guide-card-media img,
.guide-card-media svg {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.guide-card-body {
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  flex-grow: 1;
}

.guide-meta {
  display: flex;
  gap: 0.65rem;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--accent-cobalt);
  font-weight: 800;
  margin-bottom: 0.65rem;
}

.guide-card-body h2 {
  font-size: 1.24rem;
  font-weight: 900;
  margin-bottom: 0.65rem;
  line-height: 1.38;
}

.guide-card-body h2 a {
  color: var(--ink-black);
  text-decoration: none;
}

.guide-card-body h2 a:hover {
  color: var(--accent-vermilion);
}

.guide-card-body p {
  font-size: 0.94rem;
  line-height: 1.65;
  color: var(--ink-muted);
  margin-bottom: 1.25rem;
  flex-grow: 1;
}

.guide-read-link {
  font-family: var(--font-mono);
  font-size: 0.86rem;
  font-weight: 900;
  color: var(--surface-white);
  background-color: var(--ink-black);
  padding: 0.45rem 0.85rem;
  align-self: flex-start;
  text-decoration: none;
  border: var(--grid-border);
}

.guide-read-link:hover {
  background-color: var(--accent-vermilion);
  color: var(--surface-white);
}

/* SEO Articles */
.article-header {
  padding: 2.75rem 0 1.5rem;
  border-bottom: var(--grid-border-heavy);
}

.article-header h1 {
  font-size: 2.1rem;
  font-weight: 900;
  color: var(--ink-black);
  line-height: 1.3;
  margin-bottom: 0.9rem;
  letter-spacing: -0.02em;
}

.article-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--accent-cobalt);
  font-weight: 800;
}

.vermilion-note {
  font-size: 1.05rem;
  line-height: 1.75;
  color: var(--ink-black);
  background-color: var(--surface-white);
  border: var(--grid-border);
  border-left: 6px solid var(--accent-vermilion);
  box-shadow: var(--shadow-swiss);
  padding: 1.35rem 1.65rem;
  margin: 2rem 0;
}

.article-body {
  padding: 0.5rem 0 3.5rem;
}

.article-body h2 {
  font-size: 1.48rem;
  font-weight: 900;
  color: var(--ink-black);
  margin-top: 2.75rem;
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: var(--grid-border);
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.article-body h2::before {
  content: "//";
  font-family: var(--font-mono);
  font-size: 1rem;
  color: var(--accent-vermilion);
  font-weight: 900;
}

.article-body p {
  font-size: 1rem;
  line-height: 1.8;
  color: var(--ink-black);
  margin-bottom: 1.35rem;
}

.article-body ul,
.article-body ol {
  margin-bottom: 1.5rem;
  padding-left: 1.5rem;
  color: var(--ink-black);
}

.article-body li {
  margin-bottom: 0.6rem;
  line-height: 1.75;
}

.article-callout {
  background-color: var(--surface-white);
  border: var(--grid-border);
  box-shadow: var(--shadow-swiss);
  padding: 1.35rem;
  margin: 1.5rem 0;
}

.article-callout-title {
  font-weight: 900;
  color: var(--accent-vermilion);
  margin-bottom: 0.5rem;
  font-size: 1.02rem;
}

.article-callout p {
  color: var(--ink-black);
  font-size: 0.96rem;
  margin-bottom: 0;
}

.article-table-wrap {
  overflow-x: auto;
  margin: 2rem 0;
  border: var(--grid-border);
  box-shadow: var(--shadow-swiss);
  background-color: var(--surface-white);
}

.article-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.92rem;
}

.article-table th,
.article-table td {
  padding: 0.9rem 1.1rem;
  border-bottom: var(--grid-border);
  border-right: var(--grid-border);
}

.article-table th:last-child,
.article-table td:last-child {
  border-right: none;
}

.article-table th {
  background-color: var(--ink-black);
  color: var(--surface-white);
  font-family: var(--font-mono);
  font-weight: 800;
}

.article-table tr:last-child td {
  border-bottom: none;
}

.article-cta-box {
  background-color: var(--surface-white);
  border: var(--grid-border-heavy);
  box-shadow: 6px 6px 0 var(--accent-vermilion);
  padding: 2.25rem;
  text-align: left;
  margin: 3rem 0;
}

.article-cta-box h3 {
  font-size: 1.45rem;
  font-weight: 900;
  color: var(--ink-black);
  margin-bottom: 0.5rem;
}

.article-cta-box p {
  color: var(--ink-muted);
  margin-bottom: 1.5rem;
}

.related-articles {
  border-top: var(--grid-border-heavy);
  padding-top: 2rem;
  margin-top: 2.75rem;
}

.related-articles h3 {
  font-family: var(--font-mono);
  font-size: 1.2rem;
  font-weight: 900;
  color: var(--ink-black);
  margin-bottom: 1rem;
}

.related-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.related-list li a {
  font-size: 0.98rem;
  font-weight: 800;
  color: var(--ink-black);
}

.related-list li a:hover {
  color: var(--accent-vermilion);
}

/* Legal & Compliance Pages */
.legal-page {
  padding: 3rem 0 4rem;
}

.legal-header {
  margin-bottom: 2rem;
  padding-bottom: 1.5rem;
  border-bottom: var(--grid-border-heavy);
}

.legal-header h1 {
  font-size: 2.15rem;
  font-weight: 900;
  color: var(--ink-black);
  margin-bottom: 0.5rem;
}

.legal-updated {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--accent-vermilion);
  font-weight: 800;
}

.legal-content h2 {
  font-family: var(--font-mono);
  font-size: 1.3rem;
  font-weight: 900;
  color: var(--ink-black);
  margin-top: 2.25rem;
  margin-bottom: 0.75rem;
  padding-left: 0.75rem;
  border-left: 4px solid var(--accent-vermilion);
}

.legal-content p {
  font-size: 0.98rem;
  line-height: 1.8;
  color: var(--ink-black);
  margin-bottom: 1.25rem;
}

.legal-content ul {
  margin-bottom: 1.25rem;
  padding-left: 1.5rem;
  color: var(--ink-black);
}

.legal-content li {
  margin-bottom: 0.65rem;
  line-height: 1.75;
}

/* ==========================================================================
   Responsive Breakpoints
   ========================================================================== */
@media (min-width: 640px) {
  .hero-proclamation h1 {
    font-size: 2.85rem;
  }
  .features-matrix {
    grid-template-columns: repeat(2, 1fr);
  }
  .usecases-scroll {
    grid-template-columns: repeat(3, 1fr);
  }
  .streaming-scroll-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .ai-atelier-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .guides-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 880px) {
  .nav-toggle {
    display: none;
  }
  .site-nav {
    display: flex;
    flex-direction: row;
    align-items: center;
    position: static;
    background: transparent;
    padding: 0;
    box-shadow: none;
    border: none;
  }
  .nav-menu {
    flex-direction: row;
    gap: 1.25rem;
    margin-bottom: 0;
    margin-right: 1.5rem;
  }
  .nav-link {
    border-left: none;
    border-bottom: 3px solid transparent;
  }
  .nav-link:hover,
  .nav-link[aria-current="page"] {
    border-left-color: transparent;
    border-bottom-color: var(--accent-vermilion);
  }
  .nav-cta {
    width: auto;
  }
  .astrolabe-grid {
    grid-template-columns: 1.05fr 0.95fr;
  }
  .astrolabe-visual-box {
    border-bottom: none;
    border-right: var(--grid-border);
  }
  .section-banner {
    grid-template-columns: 260px 1fr;
    align-items: end;
  }
  .section-banner .section-header-main {
    grid-column: 2;
  }
  .features-matrix {
    grid-template-columns: repeat(4, 1fr);
  }
  .pricing-plaque-grid {
    grid-template-columns: repeat(3, 1fr);
    align-items: stretch;
  }
  .pricing-plaque--recommend {
    transform: translateY(-6px);
  }
  .streaming-scroll-grid {
    grid-template-columns: repeat(3, 1fr);
  }
  .ai-atelier-grid {
    grid-template-columns: repeat(3, 1fr);
  }
  .guides-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (prefers-reduced-motion: reduce) {
  * {
    animation: none !important;
    transition: none !important;
    scroll-behavior: auto !important;
  }
}