/* ==========================================================================
   Shared components — used on every page.
   Header · Buttons · Icon buttons · Segmented controls · Footer · Forms ·
   Blueprint mode
   ========================================================================== */

/* ---------- Buttons ---------- */
.btn {
  --btn-bg: var(--ink);
  --btn-fg: var(--paper);
  --btn-border: var(--btn-bg);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  min-height: 3rem;
  padding: 0 var(--space-5);
  border: 1px solid var(--btn-border);
  border-radius: var(--radius-pill);
  background: var(--btn-bg);
  color: var(--btn-fg);
  font-weight: 600;
  font-size: var(--step--1);
  letter-spacing: 0.01em;
  text-decoration: none;
  white-space: nowrap;
  transition:
    background-color var(--dur-2) var(--ease-out),
    border-color var(--dur-2) var(--ease-out),
    color var(--dur-2) var(--ease-out),
    transform var(--dur-2) var(--ease-out);
}
.btn:hover { --btn-bg: var(--signal); --btn-fg: var(--signal-ink); }
.btn:active { transform: translateY(1px); }
.btn--accent { --btn-bg: var(--signal); --btn-fg: var(--signal-ink); }
.btn--accent:hover { --btn-bg: var(--ink); --btn-fg: var(--paper); }
.btn--ghost { --btn-bg: transparent; --btn-fg: var(--ink); --btn-border: var(--line-strong); }
.btn--ghost:hover { --btn-bg: var(--ink); --btn-fg: var(--paper); --btn-border: var(--ink); }
.btn--sm { min-height: 2.5rem; padding: 0 var(--space-4); }
.btn--block { width: 100%; }

/* Arrow that nudges forward on hover */
.btn .arrow, .link-arrow .arrow {
  width: 1em; height: 1em;
  transition: transform var(--dur-2) var(--ease-out);
}
.btn:hover .arrow, .link-arrow:hover .arrow { transform: translateX(3px); }
.link-arrow:hover .arrow--out { transform: translate(2px, -2px); }

.link-arrow {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  color: var(--ink);
  font-weight: 600;
  text-decoration: none;
  border-bottom: 1px solid var(--line-strong);
  padding-bottom: 2px;
  transition: border-color var(--dur-2);
}
.link-arrow:hover { border-color: var(--signal); }

/* ---------- Icon buttons (theme, blueprint, menu) ---------- */
.icon-btn {
  display: inline-grid;
  place-items: center;
  width: 2.5rem;
  height: 2.5rem;
  flex: none;
  border-radius: var(--radius-pill);
  border: 1px solid var(--line);
  color: var(--ink);
  transition: background-color var(--dur-2), border-color var(--dur-2), color var(--dur-2);
}
.icon-btn:hover { background: var(--surface-2); border-color: var(--line-strong); }
.icon-btn[aria-pressed="true"] { background: var(--blueprint); border-color: var(--blueprint); color: #fff; }
.icon-btn svg { width: 1.15rem; height: 1.15rem; }

/* Theme toggle: shows the icon of the theme you'd switch TO. */
[data-theme-toggle] .i-sun { display: none; }
:root[data-resolved-theme="dark"] [data-theme-toggle] .i-sun { display: block; }
:root[data-resolved-theme="dark"] [data-theme-toggle] .i-moon { display: none; }

/* ---------- Site header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: var(--z-header);
  background: color-mix(in srgb, var(--paper) 86%, transparent);
  backdrop-filter: saturate(1.4) blur(14px);
  -webkit-backdrop-filter: saturate(1.4) blur(14px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--dur-3);
}
.site-header.is-scrolled { border-bottom-color: var(--line); }
.site-header__inner {
  display: flex;
  align-items: center;
  gap: var(--space-5);
  height: 4.25rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  color: var(--ink);
  text-decoration: none;
  flex: none;
}
.brand__mark { width: 2rem; height: 2rem; flex: none; }
.brand__mark-bg { fill: var(--ink); }
.brand__mark-m { stroke: var(--paper); }
.brand__mark-l { stroke: var(--signal); }
.brand__name { display: grid; line-height: 1; }
.brand__name b {
  font-weight: 800;
  font-stretch: 72%;
  font-size: 1.05rem;
  letter-spacing: 0.01em;
  text-transform: uppercase;
}
.brand__name > span:not(.visually-hidden) {
  font-family: var(--font-mono);
  font-size: 0.62rem;
  letter-spacing: 0.32em;
  text-transform: uppercase;
  color: var(--ink-3);
  margin-top: 3px;
}

.site-nav { margin-left: auto; }
.site-nav__list { display: flex; gap: var(--space-1); }
.site-nav a {
  position: relative;
  display: block;
  padding: var(--space-2) var(--space-3);
  font-size: var(--step--1);
  font-weight: 500;
  color: var(--ink-2);
  text-decoration: none;
  border-radius: var(--radius-md);
  transition: color var(--dur-2);
}
.site-nav a::after {
  content: "";
  position: absolute;
  left: var(--space-3); right: var(--space-3); bottom: 2px;
  height: 2px;
  background: var(--signal);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--dur-3) var(--ease-out);
}
.site-nav a:hover, .site-nav a[aria-current] { color: var(--ink); }
.site-nav a:hover::after, .site-nav a[aria-current]::after { transform: scaleX(1); }

.site-header__tools { display: flex; align-items: center; gap: var(--space-2); }
.nav-toggle { display: none; }

/* Mobile menu panel */
.mobile-menu {
  border-top: 1px solid var(--line);
  background: var(--paper);
  padding: var(--space-4) var(--gutter) var(--space-6);
}
.mobile-menu ul { display: grid; }
.mobile-menu a:not(.btn) {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  padding: var(--space-4) 0;
  border-bottom: 1px solid var(--line);
  color: var(--ink);
  font-size: var(--step-2);
  font-weight: 700;
  font-stretch: var(--stretch-display);
  text-decoration: none;
}
.mobile-menu a:not(.btn) small { font-family: var(--font-mono); font-size: var(--step--2); color: var(--ink-3); font-weight: 400; }
.mobile-menu .btn { margin-top: var(--space-5); }

@media (max-width: 60rem) {
  .site-nav { display: none; }
  .site-header__tools { margin-left: auto; }
  .js .nav-toggle { display: inline-grid; }
  /* Without JS the menu button can't work, so show the nav as a scrollable row instead. */
  html:not(.js) .site-nav {
    display: block;
    position: absolute;
    top: 100%; left: 0; right: 0;
    overflow-x: auto;
    background: var(--paper);
    border-bottom: 1px solid var(--line);
  }
}
@media (max-width: 35rem) {
  .site-header__cta { display: none; }
}
/* Smallest phones: the blueprint toggle stays available in the Under-the-hood section. */
@media (max-width: 24rem) {
  .site-header__tools [data-blueprint-toggle] { display: none; }
}

/* Hamburger → close icon */
.nav-toggle__bars, .nav-toggle__bars::before, .nav-toggle__bars::after {
  display: block;
  width: 1.1rem;
  height: 2px;
  background: currentColor;
  transition: transform var(--dur-2) var(--ease-out), opacity var(--dur-1);
}
.nav-toggle__bars { position: relative; }
.nav-toggle__bars::before, .nav-toggle__bars::after { content: ""; position: absolute; left: 0; }
.nav-toggle__bars::before { top: -6px; }
.nav-toggle__bars::after { top: 6px; }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars { background: transparent; }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::before { transform: translateY(6px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::after { transform: translateY(-6px) rotate(-45deg); }

/* ---------- Segmented control (filters, view toggles) ---------- */
.segmented {
  display: inline-flex;
  flex-wrap: wrap;
  gap: var(--space-1);
  padding: var(--space-1);
  border: 1px solid var(--line);
  border-radius: var(--radius-pill);
  background: var(--surface);
}
.segmented button {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  min-height: 2.5rem;
  padding: 0 var(--space-4);
  border-radius: var(--radius-pill);
  font-size: var(--step--1);
  font-weight: 500;
  color: var(--ink-2);
  transition: background-color var(--dur-2) var(--ease-out), color var(--dur-2);
}
.segmented button:hover { color: var(--ink); background: var(--surface-2); }
.segmented button[aria-pressed="true"] { background: var(--ink); color: var(--paper); }
.segmented .count {
  font-family: var(--font-mono);
  font-size: var(--step--2);
  opacity: .7;
}

/* ---------- Forms ---------- */
.field { display: grid; gap: var(--space-2); }
.field label { font-size: var(--step--1); font-weight: 600; color: var(--ink); }
.field .hint { font-size: var(--step--2); color: var(--ink-3); font-weight: 400; }
.input {
  width: 100%;
  min-height: 3rem;
  padding: var(--space-3) var(--space-4);
  border: 1px solid var(--control);
  border-radius: var(--radius-md);
  background: var(--surface);
  color: var(--ink);
  transition: border-color var(--dur-2), box-shadow var(--dur-2);
}
.input::placeholder { color: var(--ink-3); }
.input:hover { border-color: var(--ink-3); }
.input:focus-visible { outline: none; border-color: var(--focus); box-shadow: 0 0 0 3px color-mix(in srgb, var(--focus) 30%, transparent); }
textarea.input { min-height: 8rem; resize: vertical; }
select.input {
  appearance: none;
  background-image: linear-gradient(45deg, transparent 50%, var(--ink-3) 50%), linear-gradient(135deg, var(--ink-3) 50%, transparent 50%);
  background-position: calc(100% - 1.25rem) 55%, calc(100% - 0.9rem) 55%;
  background-size: 0.35rem 0.35rem;
  background-repeat: no-repeat;
  padding-right: 2.5rem;
}
.input[aria-invalid="true"] { border-color: var(--danger); }
.field-error { font-size: var(--step--1); color: var(--danger); }
.field-error:empty { display: none; }

/* ---------- Site footer ---------- */
.site-footer {
  border-top: 1px solid var(--line);
  padding-block: var(--space-8) var(--space-6);
  font-size: var(--step--1);
}
.site-footer__top {
  display: grid;
  gap: var(--space-7);
  grid-template-columns: minmax(0, 1.2fr) minmax(0, 2fr);
  padding-bottom: var(--space-7);
}
.site-footer__about p { margin-top: var(--space-4); max-width: 22rem; color: var(--ink-3); }
.site-footer__cols {
  display: grid;
  gap: var(--space-6);
  grid-template-columns: repeat(auto-fit, minmax(9rem, 1fr));
}
.site-footer h2 {
  font-family: var(--font-mono);
  font-size: var(--step--2);
  font-weight: 500;
  letter-spacing: var(--tracking-caps);
  text-transform: uppercase;
  color: var(--ink-3);
  margin-bottom: var(--space-4);
}
.site-footer__cols li + li { margin-top: var(--space-2); }
.site-footer a { color: var(--ink-2); text-decoration: none; }
.site-footer a:hover { color: var(--ink); text-decoration: underline; text-decoration-color: var(--signal); }
.socials { display: flex; gap: var(--space-2); margin-top: var(--space-5); }
.socials a { display: grid; place-items: center; width: 2.5rem; height: 2.5rem; border: 1px solid var(--line); border-radius: var(--radius-pill); }
.socials a:hover { border-color: var(--ink); }
.socials svg { width: 1rem; height: 1rem; }
.site-footer__bottom {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: var(--space-4);
  padding-top: var(--space-5);
  border-top: 1px solid var(--line);
  color: var(--ink-3);
  font-family: var(--font-mono);
  font-size: var(--step--2);
}
@media (max-width: 48rem) {
  .site-footer__top { grid-template-columns: 1fr; }
}

/* ==========================================================================
   Blueprint mode — toggled from the header. Outlines every component, labels
   it with its name, overlays the 12-column grid and shows live page metrics.
   ========================================================================== */
.blueprint-on body {
  background-image:
    linear-gradient(color-mix(in srgb, var(--blueprint) 10%, transparent) 1px, transparent 1px),
    linear-gradient(90deg, color-mix(in srgb, var(--blueprint) 10%, transparent) 1px, transparent 1px);
  background-size: 8px 8px;
}
.blueprint-on [data-component] {
  outline: 1px dashed var(--blueprint);
  outline-offset: -1px;
}
.blueprint-on [data-component]:not(.site-header) { position: relative; }
.blueprint-on [data-component]::after {
  content: "<" attr(data-component) ">";
  position: absolute;
  top: 0; left: 0;
  z-index: var(--z-blueprint);
  padding: 2px 6px;
  background: var(--blueprint);
  color: #fff;
  font: 500 10px/1.4 var(--font-mono);
  letter-spacing: 0.02em;
  pointer-events: none;
}

.bp-grid {
  position: fixed;
  inset: 0;
  z-index: var(--z-overlay);
  pointer-events: none;
}
.bp-grid .wrap {
  height: 100%;
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: var(--space-5);
}
.bp-grid i { background: color-mix(in srgb, var(--blueprint) 7%, transparent); border-inline: 1px solid color-mix(in srgb, var(--blueprint) 25%, transparent); }
@media (max-width: 48rem) {
  .bp-grid .wrap { grid-template-columns: repeat(4, 1fr); gap: var(--space-4); }
  .bp-grid i:nth-child(n + 5) { display: none; }
}

.bp-hud {
  position: fixed;
  left: var(--space-4);
  bottom: var(--space-4);
  z-index: var(--z-toast);
  width: min(19rem, calc(100vw - 2rem));
  padding: var(--space-4);
  border-radius: var(--radius-lg);
  background: color-mix(in srgb, #0b1330 94%, transparent);
  color: #dfe7ff;
  font: 400 11.5px/1.7 var(--font-mono);
  box-shadow: var(--shadow-lg);
  backdrop-filter: blur(8px);
}
.bp-hud__title { display: flex; justify-content: space-between; align-items: center; color: #fff; font-weight: 600; letter-spacing: 0.1em; margin-bottom: var(--space-2); }
.bp-hud dl { display: grid; grid-template-columns: auto 1fr; column-gap: var(--space-4); }
.bp-hud dt { color: #93a4d6; }
.bp-hud dd { text-align: right; color: #fff; font-variant-numeric: tabular-nums; }
.bp-hud button { color: #fff; border: 1px solid #3a4a80; border-radius: var(--radius-sm); padding: 0 var(--space-2); font-size: 11px; }
.bp-hud button:hover { background: #1b2a5c; }
.bp-hud__note { margin-top: var(--space-2); color: #93a4d6; font-size: 10.5px; line-height: 1.5; }
.site-footer__legal { display: flex; flex-wrap: wrap; gap: var(--space-4); }

/* Theme switch: replace the default cross-fade with a circular reveal (driven from theme.js). */
html.theme-vt::view-transition-old(root),
html.theme-vt::view-transition-new(root) { animation: none; mix-blend-mode: normal; }