/* ==========================================================================
   kastellan.dev — shared stylesheet
   Design direction: "B1 Pure Clean" — light, airy, borders carry structure.
   One dark navy band tells the security story. No build step; plain CSS.
   ========================================================================== */

/* ---- Design tokens (locked — checked by scripts/site/check-site.sh) ----- */

:root {
  --bg: #fafbfd;          /* page background */
  --surface: #ffffff;     /* cards, nav */
  --border: #e2e8f0;
  --ink: #0f172a;         /* headings */
  --body: #475569;        /* body text */
  --muted: #64748b;
  --faint: #94a3b8;
  --accent: #4f46e5;      /* indigo */
  --dark: #0f172a;        /* landing security band */
  --dark-surface: #1e293b;
  --dark-accent: #818cf8;
  --ok: #16a34a;          /* shipped */
  --warn: #d97706;        /* in progress */

  /* derived, non-contract helpers */
  --accent-strong: #4338ca;            /* hover state of --accent */
  --tint: #f1f5f9;                     /* light gray fill (chips, notes) */
  --dark-body: #cbd5e1;                /* body text on dark surfaces */
  --font-sans: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, monospace;
  --radius-s: 8px;
  --radius-m: 12px;
  --radius-l: 16px;
}

/* ---- Base ---------------------------------------------------------------- */

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 5rem;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--body);
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4 {
  color: var(--ink);
  line-height: 1.2;
  letter-spacing: -0.015em;
  margin: 0 0 0.6em;
}

h2 { font-size: clamp(1.5rem, 3vw, 2rem); }
h3 { font-size: 1.2rem; }

p {
  margin: 0 0 1em;
}

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

a:hover {
  text-decoration: underline;
  text-underline-offset: 3px;
}

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

code, kbd, pre {
  font-family: var(--font-mono);
}

::selection {
  background: rgba(79, 70, 229, 0.15);
}

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

/* ---- Layout primitives --------------------------------------------------- */

.wrap {
  max-width: 1080px;
  margin-inline: auto;
  padding-inline: clamp(1.25rem, 4vw, 2rem);
}

.section {
  padding-block: clamp(3rem, 7vw, 5rem);
}

.center {
  text-align: center;
}

/* ---- Navigation ---------------------------------------------------------- */

.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.92);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}

.nav .wrap {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  min-height: 4rem;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--ink);
  letter-spacing: -0.01em;
  margin-right: auto;
}

.nav-logo:hover {
  text-decoration: none;
  color: var(--accent);
}

.nav-logo img {
  height: 28px;
  width: auto;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.75rem;
}

.nav-links a {
  color: var(--muted);
  font-size: 0.95rem;
  font-weight: 500;
  transition: color 0.15s ease;
}

.nav-links a:hover {
  color: var(--ink);
  text-decoration: none;
}

.nav-cta {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.45rem 1.05rem;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface);
  color: var(--ink);
  font-size: 0.9rem;
  font-weight: 600;
  white-space: nowrap;
  transition: border-color 0.15s ease, color 0.15s ease;
}

.nav-cta:hover {
  border-color: var(--accent);
  color: var(--accent);
  text-decoration: none;
}

.nav-toggle {
  display: none;
  padding: 0.6rem 0.8rem;
  min-width: 44px;
  min-height: 44px;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border);
  border-radius: var(--radius-s);
  background: var(--surface);
  color: var(--ink);
  font: inherit;
  font-size: 1.1rem;
  line-height: 1;
  cursor: pointer;
}

.nav-toggle:hover {
  border-color: var(--faint);
}

/* ---- Hero ---------------------------------------------------------------- */

.hero {
  display: flex;
  align-items: center;
  gap: clamp(2rem, 5vw, 4rem);
  padding-block: clamp(3.5rem, 8vw, 6.5rem);
  background:
    radial-gradient(1100px 480px at 85% -20%, rgba(79, 70, 229, 0.06), transparent 60%);
}

.hero > :first-child {
  flex: 1.5;
  min-width: 0;
}

.hero > :last-child {
  flex: 1;
  min-width: 0;
}

.hero h1 {
  font-size: clamp(2rem, 5vw, 3.25rem);
  line-height: 1.08;
  letter-spacing: -0.025em;
  margin-bottom: 0.5em;
}

.hero h1 .accent {
  color: var(--accent);
}

.hero p {
  font-size: clamp(1.05rem, 1.6vw, 1.2rem);
  max-width: 34em;
}

.hero blockquote {
  margin: 1.5rem 0;
  padding-left: 1rem;
  border-left: 3px solid var(--border);
  font-style: italic;
  color: var(--muted);
}

.hero blockquote p {
  font-size: 1rem;
  margin: 0;
}

.hero img {
  margin-inline: auto;
}

/* ---- Buttons ------------------------------------------------------------- */

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.7rem 1.5rem;
  border: 1px solid var(--accent);
  border-radius: 10px;
  background: var(--accent);
  color: #ffffff;
  font-size: 0.95rem;
  font-weight: 600;
  line-height: 1.3;
  cursor: pointer;
  transition: background-color 0.15s ease, border-color 0.15s ease;
}

.btn:hover {
  background: var(--accent-strong);
  border-color: var(--accent-strong);
  color: #ffffff;
  text-decoration: none;
}

.btn:focus-visible {
  outline-color: var(--ink);
}

.btn-ghost {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.7rem 1.1rem;
  border-radius: 10px;
  color: var(--accent);
  font-size: 0.95rem;
  font-weight: 600;
  line-height: 1.3;
  cursor: pointer;
  transition: background-color 0.15s ease;
}

.btn-ghost:hover {
  background: rgba(79, 70, 229, 0.07);
  text-decoration: none;
}

/* ---- Chips (mono one-liners and code blocks) ------------------------------ */

.chip {
  display: inline-block;
  padding: 0.6rem 1rem;
  background: var(--tint);
  border: 1px solid var(--border);
  border-radius: var(--radius-s);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  line-height: 1.7;
  color: var(--ink);
}

pre.chip {
  display: block;
  margin: 1.25rem 0;
  padding: 1rem 1.25rem;
  overflow-x: auto;
  white-space: pre;
  text-align: left;
}

.chip-comment {
  color: var(--body);
}

/* ---- Pills --------------------------------------------------------------- */

.pills {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 1.25rem 0;
}

.pill {
  display: inline-flex;
  align-items: center;
  padding: 0.35rem 0.9rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 999px;
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--body);
  white-space: nowrap;
}

/* ---- Dark band (landing security story) ----------------------------------- */

.band {
  background: var(--dark);
  color: var(--dark-body);
  padding-block: clamp(3.5rem, 7vw, 5.5rem);
}

.band-label {
  display: block;
  margin-bottom: 0.75rem;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--dark-accent);
}

.band-title {
  color: #ffffff;
  font-size: clamp(1.5rem, 3vw, 2.1rem);
  font-weight: 700;
  margin-bottom: 1.5rem;
}

.band-cards {
  display: flex;
  flex-wrap: wrap;
  gap: 1.25rem;
  margin-block: 2rem;
}

.band-card {
  flex: 1 1 240px;
  padding: 1.5rem;
  background: var(--dark-surface);
  border: 1px solid rgba(148, 163, 184, 0.15);
  border-radius: var(--radius-m);
  font-size: 0.92rem;
  line-height: 1.55;
}

.band-card p {
  margin: 0;
}

.band-card-title {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 600;
  font-size: 1rem;
  color: var(--dark-accent);
}

.band-link {
  color: var(--faint);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.band-link:hover {
  color: var(--dark-body);
}

.band :focus-visible,
.callout :focus-visible {
  outline-color: var(--dark-accent);
}

/* ---- Card grids ----------------------------------------------------------- */

.grid-3,
.grid-2 {
  display: grid;
  gap: 1.25rem;
  margin-block: 2rem;
}

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

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

.card {
  padding: 1.5rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-m);
  transition: border-color 0.15s ease;
}

.card:hover {
  border-color: var(--faint);
}

.card-title {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 600;
  font-size: 1.02rem;
  color: var(--ink);
}

.card-text {
  margin: 0;
  font-size: 0.9rem;
  line-height: 1.55;
  color: var(--muted);
}

/* ---- Status badges --------------------------------------------------------- */

.badge-done,
.badge-wip,
.badge-plan {
  display: inline-block;
  padding: 0.18rem 0.6rem;
  border-radius: 999px;
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  vertical-align: middle;
  white-space: nowrap;
}

.badge-done {
  background: #dcfce7;
  color: #15803d;
}

.badge-wip {
  background: #fef3c7;
  color: #b45309;
}

.badge-plan {
  background: var(--tint);
  color: var(--body);
}

/* ---- Stats row -------------------------------------------------------------- */

.stats {
  display: flex;
  flex-wrap: wrap;
  gap: clamp(2rem, 5vw, 4rem);
  margin-block: 2rem;
}

.stat {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
}

.stat > :first-child {
  font-size: clamp(1.7rem, 3vw, 2.2rem);
  font-weight: 700;
  line-height: 1.15;
  color: var(--ink);
  letter-spacing: -0.02em;
}

.stat > :last-child {
  font-size: 0.85rem;
  color: var(--muted);
}

/* ---- Timeline (roadmap) ------------------------------------------------------ */

.timeline {
  list-style: none;
  margin: 2rem 0;
  padding: 0.25rem 0 0.25rem 1.75rem;
  border-left: 2px solid var(--border);
}

.timeline-item {
  position: relative;
  margin-bottom: 2.25rem;
}

.timeline-item:last-child {
  margin-bottom: 0;
}

.dot-done,
.dot-wip,
.dot-plan {
  display: inline-block;
  vertical-align: -1px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  box-shadow: 0 0 0 4px var(--bg);
}

.timeline-item > .dot-done,
.timeline-item > .dot-wip,
.timeline-item > .dot-plan {
  position: absolute;
  left: calc(-1.75rem - 7px);
  top: 0.35em;
}

.dot-done { background: var(--ok); }
.dot-wip  { background: var(--warn); }
.dot-plan { background: var(--faint); }

.timeline-title {
  display: block;
  margin-bottom: 0.35rem;
  font-weight: 600;
  font-size: 1.02rem;
  color: var(--ink);
}

.timeline-title .badge-done,
.timeline-title .badge-wip,
.timeline-title .badge-plan {
  margin-left: 0.5rem;
}

.timeline-text {
  margin: 0;
  font-size: 0.92rem;
  color: var(--body);
}

/* ---- Callout (dark box) ------------------------------------------------------- */

.callout {
  margin-block: 2rem;
  padding: clamp(1.5rem, 3vw, 2.25rem);
  background: var(--dark);
  border-radius: var(--radius-l);
  color: var(--dark-body);
  font-size: 0.95rem;
  line-height: 1.6;
}

.callout-label {
  display: block;
  margin-bottom: 0.6rem;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--dark-accent);
}

.callout p:last-child {
  margin-bottom: 0;
}

.callout a {
  color: var(--dark-accent);
}

/* ---- Note (light info box) ------------------------------------------------------ */

.note {
  margin-block: 1.5rem;
  padding: 1rem 1.25rem;
  background: var(--tint);
  border: 1px solid var(--border);
  border-radius: 10px;
  font-size: 0.9rem;
  line-height: 1.55;
  color: var(--body);
}

.note p:last-child {
  margin-bottom: 0;
}

.note a {
  color: var(--accent);
  font-weight: 500;
}

/* ---- Subpage header --------------------------------------------------------------- */

.page-head {
  padding-block: clamp(2.5rem, 6vw, 4rem) 0;
}

.page-head h1 {
  font-size: clamp(1.9rem, 4vw, 2.6rem);
  letter-spacing: -0.02em;
  margin-bottom: 0.3em;
}

.page-head .subtitle {
  font-size: 1.1rem;
  color: var(--muted);
  max-width: 42em;
}

/* ---- Diagram figures ----------------------------------------------------------------- */

figure.diagram {
  margin: 2.5rem auto;
  text-align: center;
}

figure.diagram img {
  margin-inline: auto;
  border: 1px solid var(--border);
  border-radius: var(--radius-m);
  background: var(--surface);
}

figure.diagram figcaption {
  margin-top: 0.85rem;
  font-size: 0.85rem;
  color: var(--muted);
}

/* ---- Defence-in-depth ordered list (security.html) --------------------------------- */
/* Gives the <ol> breathing room; padding-left on li adds a gap between marker and text */

ol.defence {
  margin: 1.75rem 0;
  padding-left: 2.25rem;
}

ol.defence li {
  margin-bottom: 1.25rem;
  padding-left: 0.5rem;
}

ol.defence li:last-child {
  margin-bottom: 0;
}

ol.defence li p {
  margin: 0;
}

/* ---- House rules list (contributing.html) ------------------------------------------ */
/* Gives the <ul> breathing room matching the defence-in-depth ol above it */

ul.rules {
  margin: 1.75rem 0;
  padding-left: 2.25rem;
}

ul.rules li {
  margin-bottom: 1rem;
  padding-left: 0.5rem;
  line-height: 1.6;
}

ul.rules li:last-child {
  margin-bottom: 0;
}

/* ---- Footer ------------------------------------------------------------------------ */

.footer {
  margin-top: clamp(3rem, 7vw, 5rem);
  border-top: 1px solid var(--border);
}

.footer .wrap {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem 2rem;
  padding-block: 2rem;
  font-size: 0.85rem;
  color: var(--muted);
}

.footer p {
  margin: 0;
}

.footer a {
  color: var(--muted);
}

.footer a:hover {
  color: var(--ink);
}

/* ---- Responsive: single 960px tweak + the 720px breakpoint --------------------------- */

@media (max-width: 960px) {
  .grid-3 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 719.98px) {
  .nav-toggle {
    display: inline-flex;
  }

  .nav-links {
    display: none;
  }

  .nav-links.open {
    display: flex;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    box-shadow: 0 12px 24px -16px rgba(15, 23, 42, 0.25);
    padding: 0.5rem 0;
  }

  .nav-links.open a {
    padding: 0.85rem clamp(1.25rem, 4vw, 2rem);
  }

  .nav-links.open a:hover {
    background: var(--tint);
  }

  .hero {
    flex-direction: column;
    align-items: stretch;
    text-align: left;
  }

  .hero > :last-child {
    max-width: 320px;
    margin-inline: auto;
  }

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

  .stats {
    gap: 1.5rem 2.5rem;
  }

  .band-cards {
    flex-direction: column;
  }
}

/* ---- Reduced motion -------------------------------------------------------------------- */

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}