/* ── Reset & Base ─────────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:          #FAFAF8;
  --bg-card:     #FFFFFF;
  --bg-alt:      #F3F3F0;
  --text-primary:   #1A1A1A;
  --text-secondary: #6B6B6B;
  --text-tertiary:  #A0A0A0;
  --border:      rgba(0, 0, 0, 0.07);
  --shadow-sm:   0 1px 4px rgba(0,0,0,0.06), 0 0 0 1px rgba(0,0,0,0.04);
  --shadow-md:   0 4px 20px rgba(0,0,0,0.08), 0 0 0 1px rgba(0,0,0,0.04);
  --radius-sm:   10px;
  --radius-md:   16px;
  --radius-lg:   24px;
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Helvetica Neue", Arial, sans-serif;
  --font-mono: "SF Mono", "Fira Code", "Cascadia Code", Menlo, monospace;
  --max-w: 1080px;
  --transition: 0.18s ease;
  /* notice colors */
  --notice-info-bg:     #EFF6FF;
  --notice-info-border: #BFDBFE;
  --notice-info-text:   #1E40AF;
  --notice-tip-bg:      #F0FDF4;
  --notice-tip-border:  #BBF7D0;
  --notice-tip-text:    #166534;
  --notice-upcoming-bg:     #FFFBEB;
  --notice-upcoming-border: #FDE68A;
  --notice-upcoming-text:   #92400E;
}

html { scroll-behavior: smooth; }

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }

/* ── i18n class toggle (guide.html) ──────────────────────────────────── */
body.lang-en .zh-only { display: none; }
body.lang-zh .en-only { display: none; }

/* ── Nav ──────────────────────────────────────────────────────────────── */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(250, 250, 248, 0.88);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
}

.nav-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 24px;
  height: 60px;
  display: flex;
  align-items: center;
  gap: 0;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-shrink: 0;
}

.logo-mark {
  font-size: 18px;
  font-weight: 700;
  letter-spacing: -0.5px;
  color: var(--text-primary);
}

.logo-text {
  font-size: 15px;
  font-weight: 600;
  color: var(--text-primary);
  letter-spacing: -0.3px;
}

/* Center nav links */
.nav-links {
  display: flex;
  align-items: center;
  gap: 2px;
  margin: 0 auto;
}

.nav-link {
  font-size: 14px;
  font-weight: 500;
  color: var(--text-secondary);
  padding: 6px 12px;
  border-radius: 8px;
  transition: var(--transition);
}

.nav-link:hover { background: var(--bg-alt); color: var(--text-primary); }

.nav-link-active {
  color: var(--text-primary);
  background: var(--bg-alt);
}

.nav-link-ext { color: var(--text-tertiary); }

.nav-actions {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-shrink: 0;
}

.lang-btn {
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 6px 12px;
  font-size: 13px;
  font-weight: 500;
  color: var(--text-secondary);
  cursor: pointer;
  font-family: var(--font);
  transition: var(--transition);
}

.lang-btn:hover { background: var(--bg-alt); color: var(--text-primary); }

.nav-cta {
  background: var(--text-primary);
  color: #fff;
  border-radius: 8px;
  padding: 7px 16px;
  font-size: 13px;
  font-weight: 600;
  transition: var(--transition);
}

.nav-cta:hover { opacity: 0.85; }

/* ── Buttons ──────────────────────────────────────────────────────────── */
.btn-primary {
  display: inline-block;
  background: var(--text-primary);
  color: #fff;
  border-radius: var(--radius-sm);
  padding: 13px 24px;
  font-size: 15px;
  font-weight: 600;
  transition: var(--transition);
}
.btn-primary:hover { opacity: 0.85; }
.btn-primary.btn-large { padding: 15px 28px; font-size: 16px; }

.btn-secondary {
  display: inline-block;
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 13px 24px;
  font-size: 15px;
  font-weight: 500;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}
.btn-secondary:hover { background: var(--bg-alt); }
.btn-secondary.btn-large { padding: 15px 28px; font-size: 16px; }

.btn-inverted { background: #fff; color: var(--text-primary); }
.btn-inverted:hover { opacity: 0.9; }
.btn-inverted-secondary {
  background: transparent;
  color: rgba(255,255,255,0.8);
  border-color: rgba(255,255,255,0.25);
  box-shadow: none;
}
.btn-inverted-secondary:hover { background: rgba(255,255,255,0.1); color: #fff; }

/* ── Hero ─────────────────────────────────────────────────────────────── */
.hero {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 80px 24px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
}

.hero-inner { display: flex; flex-direction: column; align-items: flex-start; gap: 20px; }

.hero-badge {
  display: inline-block;
  background: var(--bg-alt);
  border: 1px solid var(--border);
  border-radius: 100px;
  padding: 5px 14px;
  font-size: 12px;
  font-weight: 600;
  color: var(--text-secondary);
  letter-spacing: 0.4px;
  text-transform: uppercase;
}

.hero-title {
  font-size: clamp(36px, 5vw, 56px);
  font-weight: 700;
  letter-spacing: -1.5px;
  line-height: 1.1;
}

.hero-subtitle {
  font-size: 17px;
  line-height: 1.65;
  color: var(--text-secondary);
  max-width: 420px;
}

.hero-actions { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 4px; }

/* ── Device Mockup ────────────────────────────────────────────────────── */
.hero-visual { display: flex; justify-content: center; }

.device-mockup {
  width: 280px;
  height: 480px;
  background: #1A1A1A;
  border-radius: 40px;
  padding: 12px;
  box-shadow: 0 24px 64px rgba(0,0,0,0.18);
  position: relative;
}

.device-mockup::before {
  content: '';
  position: absolute;
  top: 20px;
  left: 50%;
  transform: translateX(-50%);
  width: 100px;
  height: 6px;
  background: rgba(255,255,255,0.12);
  border-radius: 100px;
}

.device-screen { background: var(--bg-card); border-radius: 30px; height: 100%; overflow: hidden; }
.mock-editor { height: 100%; display: flex; flex-direction: column; }
.mock-toolbar {
  height: 40px;
  background: var(--bg-alt);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 0 16px;
}
.mock-dot { width: 8px; height: 8px; border-radius: 50%; }
.mock-dot.red    { background: #FF5F57; }
.mock-dot.yellow { background: #FFBD2E; }
.mock-dot.green  { background: #28CA41; }
.mock-content { padding: 20px 16px; display: flex; flex-direction: column; gap: 8px; }
.mock-spacer { height: 12px; }
.mock-line { height: 8px; background: var(--bg-alt); border-radius: 100px; }
.mock-line.h1     { height: 14px; width: 70%; background: rgba(26,26,26,0.15); }
.mock-line.full   { width: 100%; }
.mock-line.long   { width: 85%; }
.mock-line.medium { width: 65%; }
.mock-line.short  { width: 45%; }
.mock-line.code   { background: #EEECEA; height: 9px; border-radius: 4px; }

/* ── Section shared ───────────────────────────────────────────────────── */
.section { padding: 96px 24px; }
.section.philosophy { background: var(--bg); }
.section.features   { background: var(--bg-alt); }
.section.roadmap    { background: var(--bg); border-top: 1px solid var(--border); }

.section-inner { max-width: var(--max-w); margin: 0 auto; }

.section-header {
  text-align: center;
  margin-bottom: 56px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
}

.section-label {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  color: var(--text-tertiary);
}

.section-title {
  font-size: clamp(28px, 4vw, 42px);
  font-weight: 700;
  letter-spacing: -1px;
  line-height: 1.15;
}

.section-desc {
  font-size: 16px;
  color: var(--text-secondary);
  line-height: 1.7;
  max-width: 560px;
}

/* ── Philosophy Grid ──────────────────────────────────────────────────── */
.phi-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }

.phi-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 32px 28px;
  display: flex; flex-direction: column; gap: 12px;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}
.phi-card:hover { box-shadow: var(--shadow-md); transform: translateY(-2px); }
.phi-icon { font-size: 28px; line-height: 1; margin-bottom: 4px; }
.phi-card h3 { font-size: 17px; font-weight: 650; letter-spacing: -0.3px; }
.phi-card p  { font-size: 14px; line-height: 1.65; color: var(--text-secondary); }

/* ── Features Grid ────────────────────────────────────────────────────── */
.feat-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }

.feat-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 28px 24px;
  display: flex; flex-direction: column; gap: 10px;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}
.feat-card:hover { box-shadow: var(--shadow-md); transform: translateY(-2px); }
.feat-icon { font-size: 24px; line-height: 1; }
.feat-card h3 { font-size: 15px; font-weight: 650; letter-spacing: -0.2px; }
.feat-card p  { font-size: 13.5px; line-height: 1.6; color: var(--text-secondary); }

/* ── Roadmap ──────────────────────────────────────────────────────────── */
.road-list { display: flex; flex-direction: column; gap: 32px; max-width: 760px; margin: 0 auto; }
.road-list-compact { gap: 24px; max-width: 100%; margin: 0; }

.road-item {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.road-version {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 16px 24px;
  border-bottom: 1px solid var(--border);
  background: var(--bg-alt);
}

.version-badge {
  display: inline-block;
  font-size: 11px;
  font-weight: 700;
  font-family: var(--font-mono);
  letter-spacing: 0.3px;
  padding: 3px 10px;
  border-radius: 6px;
}

.version-next {
  background: #ECFDF5;
  color: #065F46;
  border: 1px solid #A7F3D0;
}

.version-future {
  background: #F5F3FF;
  color: #4C1D95;
  border: 1px solid #DDD6FE;
}

.version-label {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-secondary);
}

.road-features {
  padding: 8px 0;
}

.road-feat {
  display: flex;
  gap: 14px;
  padding: 14px 24px;
  border-bottom: 1px solid var(--border);
  align-items: flex-start;
}

.road-feat:last-child { border-bottom: none; }

.road-feat-icon {
  font-size: 18px;
  line-height: 1.4;
  flex-shrink: 0;
  width: 24px;
  text-align: center;
}

.road-feat strong {
  font-size: 14px;
  font-weight: 600;
  display: block;
  margin-bottom: 3px;
}

.road-feat p, .road-feat div > :not(strong) {
  font-size: 13.5px;
  color: var(--text-secondary);
  line-height: 1.55;
}

/* ── CTA Band ─────────────────────────────────────────────────────────── */
.cta-band {
  background: var(--text-primary);
  padding: 96px 24px;
}

.cta-band-inner {
  max-width: 640px;
  margin: 0 auto;
  text-align: center;
  display: flex; flex-direction: column; align-items: center; gap: 16px;
}

.cta-band h2 {
  font-size: clamp(28px, 4vw, 42px);
  font-weight: 700;
  letter-spacing: -1px;
  line-height: 1.2;
  color: #fff;
}

.cta-band p { font-size: 16px; color: rgba(255,255,255,0.5); }

.cta-band-actions { display: flex; gap: 10px; flex-wrap: wrap; justify-content: center; margin-top: 8px; }

/* ── Footer ───────────────────────────────────────────────────────────── */
.footer {
  background: var(--bg);
  border-top: 1px solid var(--border);
  padding: 28px 24px;
}

.footer-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.footer-left { display: flex; align-items: center; gap: 10px; }
.footer-copy { font-size: 13px; color: var(--text-tertiary); }
.footer-right { display: flex; gap: 20px; }
.footer-right a { font-size: 13px; color: var(--text-secondary); font-weight: 500; transition: var(--transition); }
.footer-right a:hover { color: var(--text-primary); }

/* ── Guide Layout ─────────────────────────────────────────────────────── */
.guide-layout {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 24px;
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 48px;
  align-items: start;
  min-height: 80vh;
}

/* SIDEBAR */
.guide-sidebar {
  position: sticky;
  top: 76px;
  padding: 32px 0;
  max-height: calc(100vh - 96px);
  overflow-y: auto;
}

.sidebar-nav { display: flex; flex-direction: column; gap: 28px; }

.sidebar-section { display: flex; flex-direction: column; gap: 2px; }

.sidebar-section-title {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 1px;
  text-transform: uppercase;
  color: var(--text-tertiary);
  padding: 0 12px;
  margin-bottom: 4px;
}

.sidebar-link {
  font-size: 14px;
  color: var(--text-secondary);
  padding: 6px 12px;
  border-radius: 8px;
  display: block;
  transition: var(--transition);
}

.sidebar-link:hover { background: var(--bg-alt); color: var(--text-primary); }
.sidebar-link-active { background: var(--bg-alt); color: var(--text-primary); font-weight: 500; }

/* CONTENT */
.guide-content {
  padding: 40px 0 80px;
  min-width: 0;
}

.guide-section {
  padding: 40px 0;
  border-bottom: 1px solid var(--border);
}

.guide-section:last-child { border-bottom: none; }

.guide-h1 {
  font-size: 36px;
  font-weight: 700;
  letter-spacing: -1px;
  line-height: 1.15;
  margin-bottom: 12px;
}

.guide-lead {
  font-size: 18px;
  color: var(--text-secondary);
  margin-bottom: 28px;
  line-height: 1.6;
}

.guide-h2 {
  font-size: 24px;
  font-weight: 700;
  letter-spacing: -0.5px;
  margin-bottom: 16px;
}

.guide-h3 {
  font-size: 16px;
  font-weight: 650;
  margin: 24px 0 10px;
}

.guide-section p { font-size: 15px; line-height: 1.7; color: var(--text-secondary); margin-bottom: 12px; }
.guide-section p:last-child { margin-bottom: 0; }

.guide-ol {
  padding-left: 20px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin: 12px 0;
}

.guide-ol li { font-size: 15px; line-height: 1.6; color: var(--text-secondary); }
.guide-ol li strong { color: var(--text-primary); }

/* ── Steps ─────────────────────────────────────────────────────────────── */
.steps { display: flex; flex-direction: column; gap: 12px; margin-top: 4px; }

.step {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 16px 18px;
  box-shadow: var(--shadow-sm);
  font-size: 15px;
  line-height: 1.5;
}

.step-num {
  width: 26px;
  height: 26px;
  background: var(--text-primary);
  color: #fff;
  border-radius: 50%;
  font-size: 13px;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

/* ── Notice Boxes ─────────────────────────────────────────────────────── */
.notice {
  border-radius: var(--radius-sm);
  padding: 14px 16px;
  font-size: 13.5px;
  line-height: 1.6;
  margin: 16px 0;
  border-left: 3px solid;
}

.notice strong { display: block; margin-bottom: 3px; font-weight: 650; }

.notice-info {
  background: var(--notice-info-bg);
  border-color: var(--notice-info-border);
  color: var(--notice-info-text);
}

.notice-tip {
  background: var(--notice-tip-bg);
  border-color: var(--notice-tip-border);
  color: var(--notice-tip-text);
}

.notice-upcoming {
  background: var(--notice-upcoming-bg);
  border-color: var(--notice-upcoming-border);
  color: var(--notice-upcoming-text);
}

code {
  font-family: var(--font-mono);
  font-size: 0.88em;
  background: rgba(0,0,0,0.06);
  border-radius: 4px;
  padding: 1px 5px;
}

/* ── Guide Table ──────────────────────────────────────────────────────── */
.guide-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
  margin: 16px 0;
}

.guide-table th {
  text-align: left;
  padding: 10px 14px;
  background: var(--bg-alt);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  color: var(--text-secondary);
  border-bottom: 1px solid var(--border);
}

.guide-table th:first-child { border-radius: 8px 0 0 0; }
.guide-table th:last-child  { border-radius: 0 8px 0 0; }

.guide-table td {
  padding: 11px 14px;
  border-bottom: 1px solid var(--border);
  color: var(--text-secondary);
  line-height: 1.5;
}

.guide-table td:first-child { color: var(--text-primary); font-weight: 500; white-space: nowrap; }
.guide-table tr:last-child td { border-bottom: none; }

/* ── Mode Cards ───────────────────────────────────────────────────────── */
.mode-cards { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin: 16px 0; }

.mode-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 18px 20px;
  box-shadow: var(--shadow-sm);
}

.mode-card strong { font-size: 14px; font-weight: 650; display: block; margin-bottom: 6px; }
.mode-card p { font-size: 13.5px; line-height: 1.6; color: var(--text-secondary); margin: 0; }

/* ── Font Size Demo ───────────────────────────────────────────────────── */
.size-demo {
  display: flex;
  align-items: baseline;
  gap: 24px;
  padding: 20px 24px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  margin: 16px 0;
  box-shadow: var(--shadow-sm);
}

.size-demo span { font-weight: 600; color: var(--text-primary); }

/* ── FAQ ──────────────────────────────────────────────────────────────── */
.faq-list { display: flex; flex-direction: column; gap: 8px; }

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.faq-item summary {
  padding: 16px 20px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  color: var(--text-primary);
  transition: var(--transition);
}

.faq-item summary:hover { background: var(--bg-alt); }
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after { content: '+'; font-size: 18px; font-weight: 300; color: var(--text-tertiary); }
.faq-item[open] summary::after { content: '−'; }

.faq-item p {
  padding: 0 20px 16px;
  font-size: 14px;
  line-height: 1.65;
  color: var(--text-secondary);
  margin: 0;
}

/* ── Badge ────────────────────────────────────────────────────────────── */
.badge-recommended {
  display: inline-block;
  font-size: 10px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  background: #ECFDF5;
  color: #065F46;
  border: 1px solid #A7F3D0;
  border-radius: 6px;
  padding: 2px 7px;
  vertical-align: middle;
  margin-left: 4px;
}

/* ── Responsive ───────────────────────────────────────────────────────── */
@media (max-width: 960px) {
  .phi-grid  { grid-template-columns: repeat(2, 1fr); }
  .feat-grid { grid-template-columns: repeat(2, 1fr); }
  .guide-layout { grid-template-columns: 180px 1fr; gap: 32px; }
}

@media (max-width: 720px) {
  .hero {
    grid-template-columns: 1fr;
    padding: 56px 20px;
    gap: 48px;
    text-align: center;
  }
  .hero-inner { align-items: center; }
  .hero-subtitle { max-width: 100%; }
  .hero-visual { order: -1; }
  .device-mockup { width: 220px; height: 380px; }

  .nav-links { display: none; }
  .logo-text { display: none; }

  .phi-grid,
  .feat-grid,
  .mode-cards { grid-template-columns: 1fr; }

  .section { padding: 72px 20px; }
  .section-header { margin-bottom: 40px; }

  .guide-layout {
    grid-template-columns: 1fr;
    padding: 0 20px;
  }

  .guide-sidebar {
    position: static;
    padding: 24px 0 0;
    max-height: none;
    overflow: visible;
    border-bottom: 1px solid var(--border);
    margin-bottom: 8px;
  }

  .sidebar-nav { flex-direction: row; flex-wrap: wrap; gap: 0; }
  .sidebar-section { flex-direction: row; flex-wrap: wrap; gap: 0; align-items: center; }
  .sidebar-section-title { display: none; }
  .sidebar-link { font-size: 13px; padding: 5px 10px; }
}

@media (max-width: 480px) {
  .nav-inner { padding: 0 16px; }
  .hero-actions,
  .cta-band-actions { flex-direction: column; width: 100%; }
  .hero-actions a,
  .cta-band-actions a { text-align: center; }
}