/* ============================================================
   VARIABLES — n0d4 TSM Handbook Dark Theme
   ============================================================ */
:root {
  --n0d4-bg: #ffffff;
  --n0d4-surface: #ffffff;
  --n0d4-surface-2: #f8f9fa;
  --n0d4-surface-hover: #f1f3f4;
  --n0d4-border: #dadce0;
  --n0d4-border-strong: #bdc1c6;
  --n0d4-text: #202124;
  --n0d4-muted: #5f6368;
  --n0d4-faint: #80868b;
  --n0d4-accent: #1a73e8;
  --n0d4-accent-strong: #185abc;
  --n0d4-accent-dim: rgba(26,115,232,.08);
  --n0d4-link: #1a73e8;
  --n0d4-link-dim: rgba(26,115,232,.08);
  --n0d4-code-bg: #f1f3f4;
  --n0d4-table-stripe: #fbfbfc;
  --n0d4-warn: #d93025;
  --n0d4-warn-dim: rgba(217,48,37,.08);
  --n0d4-ok: #188038;
  --n0d4-ok-dim: rgba(24,128,56,.08);
  --sidebar-width: 280px;
  --header-height: 56px;
  --card-radius: 6px;
  --font-sans: "Roboto","Noto Sans JP",-apple-system,BlinkMacSystemFont,"Segoe UI","Helvetica Neue",Arial,sans-serif;
}

/* ============================================================
   RESET / BASE
   ============================================================ */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;scroll-padding-top:70px}
body{
  font-family:var(--font-sans);
  background:var(--n0d4-bg);
  color:var(--n0d4-text);line-height:1.75;font-size:16px;
  -webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale
}

/* ============================================================
   HEADER
   ============================================================ */
.header{
  position:fixed;top:0;left:0;right:0;height:var(--header-height);
  background:rgba(255,255,255,.92);
  border-bottom:1px solid var(--n0d4-border);
  display:flex;align-items:center;padding:0 24px;z-index:100;gap:12px
}
.header-logo{
  font-weight:900;font-size:15px;letter-spacing:.12em;
  color:var(--n0d4-accent);text-decoration:none;white-space:nowrap
}
.header-logo:hover{color:var(--n0d4-text)}
.header-title{font-size:13px;color:var(--n0d4-muted);overflow:hidden;text-overflow:ellipsis;white-space:nowrap;flex:1}
.menu-toggle{display:none;background:0 0;border:1px solid var(--n0d4-border);color:var(--n0d4-text);font-size:22px;cursor:pointer;padding:4px 12px;border-radius:var(--card-radius);line-height:1}
.menu-toggle:hover{background:var(--n0d4-border)}

/* ============================================================
   SIDEBAR
   ============================================================ */
.sidebar{
  position:fixed;top:var(--header-height);left:0;width:var(--sidebar-width);bottom:0;
  background:var(--n0d4-surface);border-right:1px solid var(--n0d4-border);
  overflow-y:auto;padding:16px 0;z-index:99;
  scrollbar-width:thin;scrollbar-color:var(--n0d4-border) transparent
}
.sidebar-backdrop{
  position:fixed;top:0;left:0;right:0;bottom:0;z-index:98;
  background:rgba(0,0,0,.5);
  opacity:0;pointer-events:none
}
.sidebar.open ~ .sidebar-backdrop,
.sidebar-backdrop.open{opacity:1;pointer-events:auto}
/* Sidebar close button */
.sidebar-close{
  display:none;position:absolute;top:8px;right:10px;z-index:1;
  background:0 0;border:1px solid var(--n0d4-border);color:var(--n0d4-muted);
  font-size:20px;cursor:pointer;padding:4px 10px;border-radius:var(--card-radius);line-height:1
}
.sidebar-section-title{cursor:pointer;user-select:none}
.sidebar-section.collapsed>.sidebar-link,
.sidebar-section.collapsed>.sidebar-link-sub{display:none}
.sidebar-section.collapsed>.sidebar-section-title::after{
  content:' ▶';font-size:9px;margin-left:4px;opacity:.5
}
.sidebar-section:not(.collapsed)>.sidebar-section-title::after{
  content:' ▼';font-size:9px;margin-left:4px;opacity:.5
}
.sidebar-close:hover{background:var(--n0d4-border);color:var(--n0d4-text)}
.sidebar::-webkit-scrollbar{width:4px}
.sidebar::-webkit-scrollbar-thumb{background:var(--n0d4-border);border-radius:var(--card-radius)}
.sidebar-section{margin-bottom:2px}
.sidebar-section-title{
  display:block;padding:7px 20px 7px 16px;font-size:11.5px;font-weight:700;letter-spacing:.08em;
  color:var(--n0d4-accent);text-transform:uppercase;border-left:2px solid var(--n0d4-accent)
}
.sidebar-section-title:hover{color:var(--n0d4-text)}
.sidebar-link{
  display:block;padding:5px 20px 5px 22px;font-size:13px;
  color:var(--n0d4-muted);text-decoration:none;
  border-left:2px solid transparent
}
.sidebar-link:hover{color:var(--n0d4-text);background:rgba(26,115,232,.025);border-left-color:var(--n0d4-border)}
.sidebar-link-sub{padding-left:34px;font-size:12px}

/* ============================================================
   MAIN LAYOUT
   ============================================================ */
.main{margin-left:var(--sidebar-width);margin-top:var(--header-height);padding:48px 56px 100px;max-width:1000px}

/* ============================================================
   TYPOGRAPHY
   ============================================================ */
h1{
  font-size:28px;font-weight:700;margin-bottom:16px;color:var(--n0d4-text);
  letter-spacing:-.02em;line-height:1.4
}
h2{
  font-size:22px;font-weight:700;margin:48px 0 20px;color:var(--n0d4-text);letter-spacing:-.01em
}
h3{
  font-size:19px;font-weight:600;margin:32px 0 16px;color:var(--n0d4-text);letter-spacing:.01em
}
h4{
  font-size:16px;font-weight:600;margin:24px 0 12px;color:var(--n0d4-text);letter-spacing:.01em
}
p{margin-bottom:16px;max-width:75ch}
a{color:var(--n0d4-link);text-decoration:none}
a:hover{text-decoration:underline;color:#1a73e8}
strong{color:var(--n0d4-text);font-weight:600}
em{color:var(--n0d4-accent);font-style:normal;font-weight:500}

blockquote{
  border-left:3px solid var(--n0d4-accent);padding:16px 28px;margin:20px 0 28px;
  background:rgba(26,115,232,.04);border-radius:var(--card-radius);
  font-size:14.5px;color:var(--n0d4-muted);line-height:1.8
}
blockquote p{margin-bottom:8px}
blockquote p:last-child{margin-bottom:0}
ul,ol{margin:12px 0 20px 24px}
li{margin-bottom:6px}
code{
  font-family:"SF Mono","Fira Code","Cascadia Code",monospace;font-size:13px;
  background:var(--n0d4-code-bg);padding:2px 8px;border-radius:var(--card-radius);color:#b8860b
}
hr{border:none;height:1px;background:linear-gradient(to right,transparent,var(--n0d4-border),transparent);margin:64px 0}

/* ============================================================
   TABLE
   ============================================================ */
.table-wrap{overflow-x:auto;margin:20px 0 28px;border-radius:var(--card-radius);border:1px solid var(--n0d4-border)}
table{width:100%;border-collapse:collapse;font-size:13.5px}
thead{background:var(--n0d4-surface)}
th{
  padding:12px 18px;text-align:left;font-weight:700;font-size:12.5px;letter-spacing:.04em;
  color:var(--n0d4-accent);border-bottom:2px solid var(--n0d4-border);white-space:nowrap
}
td{padding:11px 18px;border-bottom:1px solid var(--n0d4-border);vertical-align:top;line-height:1.75}
tbody tr:nth-child(even){background:var(--n0d4-table-stripe)}
tbody tr:hover{background:var(--n0d4-accent-dim)}

/* ============================================================
   COMPONENTS
   ============================================================ */

/* Hero */
.hero{margin-bottom:40px}
.hero-meta{font-size:14px;color:var(--n0d4-muted);margin-top:12px}
.hero-tag{
  display:inline-block;padding:3px 14px;border:1px solid var(--n0d4-accent);
  color:var(--n0d4-accent);font-size:11px;font-weight:700;letter-spacing:.1em;
  border-radius:var(--card-radius);margin-right:10px;text-transform:uppercase
}

/* Insight */
.insight{
  border:1px solid var(--n0d4-accent);border-radius:var(--card-radius);padding:18px 26px;
  margin:20px 0 28px;background:var(--n0d4-accent-dim);font-size:14.5px;line-height:1.8
}
.insight strong{color:var(--n0d4-accent)}

/* Footer */
.footer{margin-top:72px;padding-top:28px;border-top:1px solid var(--n0d4-border);font-size:13px;color:var(--n0d4-muted);text-align:center;line-height:1.8}

/* Reference Links */
.ref-links{margin:16px 0 24px;padding:18px 22px;background:var(--n0d4-surface);border:1px solid var(--n0d4-border);border-radius:var(--card-radius)}
.ref-links-title{font-size:12px;font-weight:700;letter-spacing:.06em;color:var(--n0d4-muted);text-transform:uppercase;margin-bottom:12px}
.ref-links a{
  display:inline-block;margin:3px 6px 3px 0;font-size:13px;padding:4px 12px;
  background:rgba(26,115,232,.06);border:1px solid var(--n0d4-border);
  border-radius:var(--card-radius);color:var(--n0d4-link);white-space:normal
}
.ref-links a:hover{background:rgba(26,115,232,.12);border-color:var(--n0d4-link);text-decoration:none}

/* ============================================================
   TACTIC CARD GRID
   ============================================================ */
.tactic-grid{
  display:grid;
  grid-template-columns:repeat(auto-fill, minmax(340px, 1fr));
  gap:20px;
  margin:20px 0 28px;
}
.tactic-card{
  background:var(--n0d4-surface);border:1px solid var(--n0d4-border);border-radius:var(--card-radius);
  padding:20px;display:flex;flex-direction:column;gap:10px;
  position:relative;overflow:hidden;
}
.tactic-card:hover{
  border-color:var(--n0d4-accent);
}
.tactic-card-header{
  display:flex;align-items:flex-start;justify-content:space-between;gap:8px;
}
.tactic-card-title{
  font-size:15px;font-weight:700;color:var(--n0d4-text);line-height:1.4;flex:1;
}
.tactic-card-badge{
  display:inline-flex;align-items:center;gap:4px;
  padding:2px 10px;border-radius:var(--card-radius);font-size:10.5px;font-weight:700;
  letter-spacing:.04em;white-space:nowrap;flex-shrink:0;
}
.tactic-card-badge.cat{background:var(--n0d4-accent-dim);color:var(--n0d4-accent);border:1px solid rgba(26,115,232,.14)}
.tactic-card-badge.diff{background:rgba(26,115,232,.07);color:#7c7c88;border:1px solid rgba(26,115,232,.12)}
.tactic-card-badge.metric{background:rgba(26,115,232,.07);color:#a8a8b3;border:1px solid rgba(26,115,232,.12)}
.tactic-card-desc{
  font-size:13.5px;color:var(--n0d4-text);line-height:1.75;
}
.tactic-card-meta{
  display:flex;flex-wrap:wrap;gap:6px;margin-top:auto;padding-top:10px;
  border-top:1px solid rgba(26,115,232,.04);
}
.tactic-card-meta-item{
  font-size:12px;color:var(--n0d4-muted);line-height:1.5;
}
.tactic-card-meta-item strong{color:var(--n0d4-accent);font-weight:600;font-size:12px}

/* ============================================================
   BACK TO TOP LINK
   ============================================================ */
.back-link{
  display:inline-flex;align-items:center;gap:6px;margin-bottom:24px;
  font-size:13px;color:var(--n0d4-muted);text-decoration:none
}
.back-link:hover{color:var(--n0d4-accent);text-decoration:none}
.back-link::before{content:'←';font-size:14px}

/* ============================================================
   SEARCH INPUT
   ============================================================ */
.search-input{
  width:100%;max-width:180px;padding:4px 10px;
  background:var(--n0d4-surface-2);border:1px solid #000;
  color:var(--n0d4-text);font-family:var(--font-sans);font-size:13px;
  outline:none
}
.search-input:focus{border-color:var(--n0d4-accent)}
.search-input::placeholder{color:var(--n0d4-muted)}

/* ============================================================
   BACK TO TOP
   ============================================================ */
.back-to-top{
  position:fixed;bottom:32px;right:32px;z-index:1000;
  width:44px;height:44px;
  background:var(--n0d4-surface);border:1px solid #000;
  color:var(--n0d4-accent);font-size:20px;cursor:pointer;
  display:flex;align-items:center;justify-content:center;
  opacity:0;pointer-events:none
}
.back-to-top.visible{opacity:1;pointer-events:auto}
.back-to-top:hover{background:var(--n0d4-border)}

/* ============================================================
   READING PROGRESS BAR
   ============================================================ */
.progress-bar{
  position:fixed;top:var(--header-height);left:0;height:2px;width:0%;
  background:var(--n0d4-accent);z-index:99;transition:none
}

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media(max-width:768px){
  .menu-toggle{display:block}
  .sidebar{transform:translateX(-100%);will-change:transform}
  .sidebar.open{transform:translateX(0)}
  .sidebar-backdrop{display:block}
  .sidebar-close{display:block}
  .sidebar-link{padding:11px 20px 11px 22px;min-height:44px;display:flex;align-items:center}
  .sidebar-link-sub{padding-left:34px}
  .main{margin-left:0;padding:24px 20px 60px}
  .search-input{max-width:120px}
  .header-title{display:none}
  .tactic-grid{grid-template-columns:1fr}
  .progress-bar{z-index:101}
  h1{font-size:26px}
  h2{font-size:21px}
  body{font-size:15px;line-height:1.8}
  th{white-space:normal;padding:10px 12px}
  td{padding:9px 12px}
  ul,ol{margin-left:18px}
  blockquote{padding:14px 20px}
  p{max-width:100%;overflow-wrap:break-word;word-break:break-word}
  pre,code{white-space:pre-wrap;word-break:break-word}
  .tactic-card-desc{overflow-wrap:break-word}
  .main{overflow-x:hidden}
}

@media(max-width:480px){
  h1{font-size:22px}
  h2{font-size:17px}
  body{font-size:14px;line-height:1.75}
  .main{padding:16px 14px 40px}
  .tactic-card{padding:16px}
  .insight{padding:14px 18px}
  .table-wrap{margin:14px 0 20px}
  th{padding:8px 10px;font-size:11.5px}
  td{padding:7px 10px;font-size:12.5px}
  blockquote{padding:12px 16px;margin:14px 0 20px}
  ul,ol{margin-left:14px}
  .hero h1{font-size:20px}
  .sidebar-link{font-size:12.5px;padding:10px 16px 10px 18px}
  .sidebar-link-sub{padding-left:28px}
}

/* ============================================================
   PRINT
   ============================================================ */
@media print {
  .sidebar,.header,.menu-toggle{display:none!important}
  .main{margin:0;padding:20px;max-width:none}
  body{background:#fff;color:#000;font-size:11px;line-height:1.5}
  table{font-size:10px}
  a{color:#000}
  .insight,.tactic-card{border-color:var(--n0d4-muted);background:#f8f8fa}
}

@media (prefers-reduced-motion: reduce) {
  *,*::before,*::after{
    animation-duration:0.01ms!important;animation-iteration-count:1!important;
    transition-duration:0.01ms!important;scroll-behavior:auto!important
  }
}


/* Deep dive additions */
.kicker{font-size:12px;font-weight:700;letter-spacing:.12em;color:var(--n0d4-accent);text-transform:uppercase;margin-bottom:10px}
.lead{font-size:17px;line-height:1.75;color:var(--n0d4-muted);max-width:78ch;margin-bottom:24px}
.page-nav{display:flex;flex-wrap:wrap;gap:8px;margin:24px 0 36px;padding:18px;background:var(--n0d4-surface);border:1px solid var(--n0d4-border)}
.page-nav a{font-size:12.5px;padding:5px 10px;border:1px solid var(--n0d4-border);background:rgba(26,115,232,.05)}
.framework-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:16px;margin:22px 0 30px}
.framework-card{background:var(--n0d4-surface);border:1px solid var(--n0d4-border);padding:18px}
.framework-card h4{margin:0 0 8px;color:var(--n0d4-text);font-size:15px}.framework-card p{font-size:13.5px;color:var(--n0d4-muted);margin:0;line-height:1.8}
.template-box{background:#111;border:1px solid var(--n0d4-border);padding:18px 20px;margin:16px 0 24px}.template-box h4{margin-top:0}.template-box code{display:block;white-space:pre-wrap;line-height:1.8;padding:14px;margin-top:8px;color:#e6e6eb;background:#fafafb;border:1px solid #000}
.decision-table td:first-child{font-weight:700;color:var(--n0d4-text);white-space:nowrap}.metric-pill{display:inline-block;font-size:11px;color:#a8a8b3;border:1px solid rgba(26,115,232,.14);padding:2px 8px;margin:2px;background:rgba(26,115,232,.07)}
@media(max-width:768px){.lead{font-size:15px}.page-nav{padding:14px}.framework-grid{grid-template-columns:1fr}.decision-table td:first-child{white-space:normal}}