:root {
  color-scheme: light;
  --theme-font-ui: "SF Pro Text", "SF Pro Display", "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  --theme-font-display: var(--theme-font-ui);
  --theme-page-bg: linear-gradient(180deg, #f7f9fc 0%, #f1f5fa 52%, #e7edf5 100%);
  --theme-page-bg-fixed: fixed;
  --theme-page-glow:
    radial-gradient(circle at 12% 10%, rgba(46, 93, 144, 0.1), transparent 30%),
    radial-gradient(circle at 88% 8%, rgba(15, 23, 36, 0.06), transparent 22%),
    linear-gradient(180deg, rgba(255, 255, 255, 0.58), rgba(255, 255, 255, 0));
  --theme-surface: rgba(255, 255, 255, 0.82);
  --theme-surface-strong: #ffffff;
  --theme-surface-muted: #e7edf4;
  --theme-surface-overlay: rgba(255, 255, 255, 0.72);
  --theme-border: rgba(27, 42, 60, 0.1);
  --theme-border-strong: rgba(27, 42, 60, 0.16);
  --theme-text: #0f1724;
  --theme-text-muted: #5a6779;
  --theme-text-soft: #8390a1;
  --theme-accent: #2e5d90;
  --theme-accent-strong: #1f466e;
  --theme-accent-soft: rgba(46, 93, 144, 0.1);
  --theme-accent-rgb: 46, 93, 144;
  --theme-accent-line: rgba(46, 93, 144, 0.24);
  --theme-accent-wash: linear-gradient(180deg, rgba(46, 93, 144, 0.14), rgba(46, 93, 144, 0.03));
  --theme-accent-wash-soft: linear-gradient(180deg, rgba(46, 93, 144, 0.1), rgba(46, 93, 144, 0.02));
  --theme-neutral-strong: #0f1724;
  --theme-neutral-muted: #d7e0ea;
  --theme-ink-soft-fill: rgba(15, 23, 36, 0.08);
  --theme-ink-strong-fill: rgba(15, 23, 36, 0.14);
  --theme-shadow-xs: 0 1px 2px rgba(15, 23, 36, 0.06);
  --theme-shadow-sm: 0 18px 38px rgba(15, 23, 36, 0.08);
  --theme-shadow-md: 0 32px 72px rgba(15, 23, 36, 0.14);
  --theme-shadow-lg: 0 52px 120px rgba(15, 23, 36, 0.18);
  --theme-radius-sm: 14px;
  --theme-radius-md: 22px;
  --theme-radius-lg: 30px;
  --theme-radius-pill: 999px;
  --theme-space-1: 0.5rem;
  --theme-space-2: 0.75rem;
  --theme-space-3: 1rem;
  --theme-space-4: 1.5rem;
  --theme-space-5: 2rem;
  --theme-space-6: 3rem;
  --theme-space-7: 4rem;
  --theme-card-pad: 1.3rem;
  --theme-card-pad-lg: 1.45rem;
  --theme-shell-max: 74rem;
  --theme-shell-wide: 80rem;
  --theme-header-max: 82rem;
  --theme-header-bg: rgba(249, 251, 254, 0.72);
  --theme-toggle-bg: rgba(255, 255, 255, 0.88);
  --theme-toggle-border: rgba(15, 23, 36, 0.1);
  --theme-toggle-shadow: 0 12px 28px rgba(15, 23, 36, 0.08);
  --theme-toggle-ink: #0f1724;
  --theme-toggle-muted: #6f7c8d;
  --theme-track-bg: #d3dbe5;
  --theme-knob-bg: #ffffff;
  --theme-focus: rgba(46, 93, 144, 0.52);
  --theme-motion-fast: 160ms;
  --theme-motion-mid: 240ms;
  --theme-ease: cubic-bezier(0.2, 0.65, 0.22, 1);
}

html[data-theme="dark"] {
  color-scheme: dark;
  --theme-page-bg: linear-gradient(180deg, #0b1118 0%, #0d141d 52%, #111b26 100%);
  --theme-page-bg-fixed: fixed;
  --theme-page-glow:
    radial-gradient(circle at 14% 12%, rgba(127, 177, 236, 0.12), transparent 28%),
    radial-gradient(circle at 86% 8%, rgba(255, 255, 255, 0.03), transparent 22%),
    linear-gradient(180deg, rgba(255, 255, 255, 0.02), rgba(255, 255, 255, 0));
  --theme-surface: rgba(18, 25, 35, 0.88);
  --theme-surface-strong: #121a24;
  --theme-surface-muted: #1b2634;
  --theme-surface-overlay: rgba(17, 24, 34, 0.78);
  --theme-border: rgba(210, 223, 237, 0.09);
  --theme-border-strong: rgba(210, 223, 237, 0.15);
  --theme-text: #edf4fb;
  --theme-text-muted: #a8b6c7;
  --theme-text-soft: #728092;
  --theme-accent: #7fb1ec;
  --theme-accent-strong: #9ac5f5;
  --theme-accent-soft: rgba(127, 177, 236, 0.14);
  --theme-accent-rgb: 127, 177, 236;
  --theme-accent-line: rgba(127, 177, 236, 0.28);
  --theme-accent-wash: linear-gradient(180deg, rgba(127, 177, 236, 0.16), rgba(127, 177, 236, 0.04));
  --theme-accent-wash-soft: linear-gradient(180deg, rgba(127, 177, 236, 0.11), rgba(127, 177, 236, 0.03));
  --theme-neutral-strong: #edf4fb;
  --theme-neutral-muted: #283549;
  --theme-ink-soft-fill: rgba(237, 244, 251, 0.08);
  --theme-ink-strong-fill: rgba(237, 244, 251, 0.14);
  --theme-shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.2);
  --theme-shadow-sm: 0 20px 42px rgba(0, 0, 0, 0.28);
  --theme-shadow-md: 0 34px 78px rgba(0, 0, 0, 0.38);
  --theme-shadow-lg: 0 50px 128px rgba(0, 0, 0, 0.5);
  --theme-header-bg: rgba(12, 18, 27, 0.8);
  --theme-toggle-bg: rgba(16, 24, 35, 0.88);
  --theme-toggle-border: rgba(210, 223, 237, 0.08);
  --theme-toggle-shadow: 0 14px 30px rgba(0, 0, 0, 0.24);
  --theme-toggle-ink: #edf4fb;
  --theme-toggle-muted: #8d9caf;
  --theme-track-bg: #334254;
  --theme-knob-bg: #f6fbff;
  --theme-focus: rgba(127, 177, 236, 0.58);
}

html,
body {
  min-height: 100%;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--theme-page-bg);
  background-attachment: var(--theme-page-bg-fixed);
  color: var(--theme-text);
  font-family: var(--theme-font-ui);
  transition:
    background var(--theme-motion-mid) var(--theme-ease),
    color var(--theme-motion-fast) var(--theme-ease);
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background: var(--theme-page-glow);
}

a,
button {
  transition:
    color var(--theme-motion-fast) var(--theme-ease),
    background-color var(--theme-motion-fast) var(--theme-ease),
    border-color var(--theme-motion-fast) var(--theme-ease),
    box-shadow var(--theme-motion-mid) var(--theme-ease),
    transform var(--theme-motion-mid) var(--theme-ease);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  width: min(var(--theme-header-max), calc(100vw - 2rem));
  margin: 0 auto;
  padding: 1rem 0 0;
}

.site-header-inner {
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 1rem;
  padding: 0.9rem 1rem;
  border: 1px solid var(--theme-border-strong);
  border-radius: var(--theme-radius-lg);
  background: var(--theme-header-bg);
  box-shadow: var(--theme-shadow-sm);
  backdrop-filter: blur(20px);
}

.site-brand {
  display: grid;
  gap: 0.15rem;
  text-decoration: none;
  color: inherit;
}

.site-brand-mark {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--theme-accent);
}

.site-brand-copy {
  font-size: 0.88rem;
  line-height: 1.3;
  color: var(--theme-text-soft);
}

.site-nav {
  display: flex;
  justify-content: center;
  gap: 1rem;
  flex-wrap: wrap;
}

.site-nav a {
  position: relative;
  padding-bottom: 0.14rem;
  color: var(--theme-text-muted);
  text-decoration: none;
  font-size: 0.76rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.site-nav a::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 1px;
  background: var(--theme-accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--theme-motion-mid) var(--theme-ease);
}

.site-nav a:hover,
.site-nav a[aria-current="page"],
.site-nav a:focus-visible {
  color: var(--theme-text);
  outline: none;
}

.site-nav a:hover::after,
.site-nav a[aria-current="page"]::after,
.site-nav a:focus-visible::after {
  transform: scaleX(1);
}

.theme-toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.65rem;
  padding: 0.58rem 0.7rem 0.58rem 0.82rem;
  border: 1px solid var(--theme-toggle-border);
  border-radius: var(--theme-radius-pill);
  background: var(--theme-toggle-bg);
  box-shadow: var(--theme-toggle-shadow);
  color: var(--theme-toggle-ink);
  font: inherit;
  cursor: pointer;
  backdrop-filter: blur(14px);
}

.theme-toggle-label {
  font-size: 0.74rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.theme-toggle-state {
  font-size: 0.68rem;
  color: var(--theme-toggle-muted);
  text-transform: uppercase;
  letter-spacing: 0.14em;
}

.theme-toggle-switch {
  position: relative;
  width: 3rem;
  height: 1.5rem;
  border-radius: var(--theme-radius-pill);
  background: var(--theme-track-bg);
  flex: 0 0 auto;
  transition: background var(--theme-motion-fast) var(--theme-ease);
}

.theme-toggle-switch::after {
  content: "";
  position: absolute;
  top: 0.19rem;
  left: 0.2rem;
  width: 1.08rem;
  height: 1.08rem;
  border-radius: 50%;
  background: var(--theme-knob-bg);
  box-shadow: 0 3px 8px rgba(0, 0, 0, 0.16);
  transition: transform var(--theme-motion-mid) var(--theme-ease);
}

html[data-theme="dark"] .theme-toggle-switch::after {
  transform: translateX(1.48rem);
}

.theme-toggle:hover {
  border-color: var(--theme-border-strong);
}

.theme-toggle:focus-visible {
  outline: 2px solid var(--theme-focus);
  outline-offset: 3px;
}

.specimen-shell {
  width: min(68rem, calc(100vw - 2rem));
  margin: 0 auto;
  padding: clamp(2.5rem, 5vw, 4.5rem) 0 2.5rem;
}

.specimen-intro {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  gap: 1.5rem;
  margin-bottom: 1.5rem;
}

.specimen-kicker {
  margin: 0 0 0.4rem;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--theme-accent);
}

.specimen-title {
  margin: 0;
  font-size: clamp(2rem, 5vw, 3.8rem);
  line-height: 0.92;
  letter-spacing: -0.07em;
  font-weight: 650;
  color: var(--theme-text);
}

.specimen-note {
  max-width: 28rem;
  margin: 0;
  font-size: 1rem;
  line-height: 1.75;
  color: var(--theme-text-muted);
}

.specimen-stage {
  position: relative;
  overflow: hidden;
  display: grid;
  place-items: center;
  padding: clamp(1.4rem, 4vw, 2.75rem);
  border: 1px solid var(--theme-border-strong);
  border-radius: var(--theme-radius-lg);
  background:
    linear-gradient(180deg, var(--theme-surface-strong) 0%, var(--theme-surface) 100%);
  box-shadow: var(--theme-shadow-md);
}

.specimen-stage::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    var(--theme-accent-wash-soft),
    linear-gradient(var(--theme-border), var(--theme-border)),
    linear-gradient(90deg, var(--theme-border), var(--theme-border));
  background-size: auto, 100% 1px, 1px 100%;
  background-position: 0 0, center center, center center;
  background-repeat: no-repeat;
  opacity: 0.72;
  pointer-events: none;
}

.specimen-stage > * {
  position: relative;
  z-index: 1;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

@media (max-width: 980px) {
  .site-header-inner {
    grid-template-columns: 1fr;
    justify-items: start;
  }

  .site-nav {
    justify-content: flex-start;
  }

  .theme-toggle {
    justify-self: start;
  }

  .specimen-intro {
    flex-direction: column;
    align-items: flex-start;
  }
}

@media (prefers-reduced-motion: reduce) {
  body,
  a,
  button,
  .site-nav a::after,
  .theme-toggle-switch,
  .theme-toggle-switch::after {
    transition: none;
  }
}