/* ==========================================================================
   Design tokens and base layer
   Colour values live in theme-light.css and theme-dark.css. Everything here is
   theme independent: type scale, spacing, radii, motion, layout and the reset.
   ========================================================================== */

:root {
  /* Typeface stacks */
  --font-display: "Space Grotesk", "Segoe UI", Roboto, system-ui, sans-serif;
  --font-body: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, system-ui, sans-serif;

  /* Type scale. Body steps use a 1.25 ratio, display sizes are fluid. */
  --text-2xs: 0.6875rem;
  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-md: 1.0625rem;
  --text-lg: 1.25rem;
  --text-xl: 1.5rem;
  --text-2xl: 1.875rem;

  --display-xs: clamp(1.375rem, 1.24rem + 0.65vw, 1.75rem);
  --display-sm: clamp(1.625rem, 1.4rem + 1.1vw, 2.25rem);
  --display-md: clamp(2rem, 1.6rem + 1.95vw, 3.125rem);
  --display-lg: clamp(2.5rem, 1.85rem + 3.1vw, 4.25rem);
  --display-xl: clamp(2.875rem, 1.9rem + 4.6vw, 5.75rem);

  --leading-tight: 1.06;
  --leading-snug: 1.22;
  --leading-normal: 1.5;
  --leading-relaxed: 1.72;

  --tracking-tight: -0.022em;
  --tracking-snug: -0.012em;
  --tracking-normal: 0;
  --tracking-wide: 0.06em;
  --tracking-caps: 0.16em;

  --weight-regular: 400;
  --weight-medium: 500;
  --weight-semibold: 600;
  --weight-bold: 700;

  /* Spacing, 4px base */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;
  --space-32: 8rem;

  /* Vertical rhythm between major page sections */
  --section-gap: clamp(3.75rem, 2.6rem + 5.2vw, 6.75rem);
  --section-gap-sm: clamp(2.75rem, 2rem + 3.4vw, 4.75rem);

  /* Radii */
  --radius-xs: 4px;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --radius-xl: 26px;
  --radius-pill: 999px;

  /* Layout */
  --container-max: 1240px;
  --container-narrow: 760px;
  --container-pad: clamp(1.25rem, 1rem + 2.4vw, 3rem);
  --header-height: 4.5rem;
  --border-width: 1px;

  /* Motion. Entering uses ease-out, leaving uses ease-in. */
  --ease-out: cubic-bezier(0.22, 1, 0.36, 1);
  --ease-in: cubic-bezier(0.64, 0, 0.78, 0);
  --ease-in-out: cubic-bezier(0.65, 0, 0.35, 1);
  --duration-fast: 150ms;
  --duration-base: 240ms;
  --duration-slow: 400ms;
  --duration-page: 480ms;

  /* Focus */
  --focus-width: 2px;
  --focus-offset: 3px;

  color-scheme: dark;
}

[data-theme="light"] {
  color-scheme: light;
}

/* --------------------------------------------------------------------------
   Reset
   -------------------------------------------------------------------------- */

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-height) + var(--space-6));
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font-body);
  font-size: var(--text-md);
  font-weight: var(--weight-regular);
  line-height: var(--leading-relaxed);
  color: var(--text);
  background-color: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  transition: background-color var(--duration-base) var(--ease-in-out),
    color var(--duration-base) var(--ease-in-out);
}

h1, h2, h3, h4, h5, h6 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: var(--weight-semibold);
  line-height: var(--leading-snug);
  letter-spacing: var(--tracking-snug);
  color: var(--text-strong);
}

p {
  margin: 0;
}

ul, ol {
  margin: 0;
  padding: 0;
}

img, svg, video {
  display: block;
  max-width: 100%;
}

img {
  height: auto;
}

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

button, input, select, textarea {
  font: inherit;
  color: inherit;
}

button {
  border: none;
  background: none;
  cursor: pointer;
}

hr {
  border: none;
  border-top: var(--border-width) solid var(--border);
  margin: 0;
}

code, pre, kbd, samp {
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
  font-size: 0.9em;
}

::selection {
  background-color: var(--accent-soft);
  color: var(--text-strong);
}

:focus-visible {
  outline: var(--focus-width) solid var(--accent-strong);
  outline-offset: var(--focus-offset);
  border-radius: var(--radius-xs);
}

:focus:not(:focus-visible) {
  outline: none;
}

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

.shell {
  width: 100%;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--container-pad);
}

.shell--narrow {
  max-width: var(--container-narrow);
}

.section {
  padding-block: var(--section-gap);
}

.section--tight {
  padding-block: var(--section-gap-sm);
}

.section--divided {
  border-top: var(--border-width) solid var(--border);
}

.stack {
  display: flex;
  flex-direction: column;
}

.stack-2 { gap: var(--space-2); }
.stack-3 { gap: var(--space-3); }
.stack-4 { gap: var(--space-4); }
.stack-6 { gap: var(--space-6); }
.stack-8 { gap: var(--space-8); }
.stack-12 { gap: var(--space-12); }

.cluster {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-3);
}

.grid-auto {
  display: grid;
  gap: var(--space-6);
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 17rem), 1fr));
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: absolute;
  top: var(--space-3);
  left: var(--space-3);
  z-index: 200;
  padding: var(--space-3) var(--space-5);
  border-radius: var(--radius-sm);
  background-color: var(--accent-strong);
  color: var(--accent-contrast);
  font-family: var(--font-display);
  font-size: var(--text-sm);
  font-weight: var(--weight-semibold);
  transform: translateY(-160%);
  transition: transform var(--duration-base) var(--ease-out);
}

.skip-link:focus-visible {
  transform: translateY(0);
}

/* --------------------------------------------------------------------------
   Type primitives
   -------------------------------------------------------------------------- */

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  font-family: var(--font-display);
  font-size: var(--text-xs);
  font-weight: var(--weight-medium);
  letter-spacing: var(--tracking-caps);
  text-transform: uppercase;
  color: var(--accent-strong);
}

.eyebrow::before {
  content: "";
  width: 1.75rem;
  height: 1px;
  background-color: currentColor;
  opacity: 0.55;
}

.eyebrow--plain::before {
  display: none;
}

.display-xl { font-size: var(--display-xl); line-height: var(--leading-tight); letter-spacing: var(--tracking-tight); }
.display-lg { font-size: var(--display-lg); line-height: var(--leading-tight); letter-spacing: var(--tracking-tight); }
.display-md { font-size: var(--display-md); }
.display-sm { font-size: var(--display-sm); }
.display-xs { font-size: var(--display-xs); }

.lede {
  font-size: var(--text-lg);
  line-height: var(--leading-normal);
  color: var(--text-secondary);
  max-width: 62ch;
}

.body-text {
  color: var(--text-secondary);
  max-width: 68ch;
}

.meta-text {
  font-family: var(--font-display);
  font-size: var(--text-xs);
  letter-spacing: var(--tracking-wide);
  text-transform: uppercase;
  color: var(--text-muted);
}

.text-strong { color: var(--text-strong); }
.text-muted { color: var(--text-muted); }
.text-accent { color: var(--accent-strong); }

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

.btn {
  --btn-bg: transparent;
  --btn-fg: var(--text-strong);
  --btn-border: var(--border-strong);
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-3);
  min-height: 2.875rem;
  padding: var(--space-3) var(--space-6);
  border: var(--border-width) solid var(--btn-border);
  border-radius: var(--radius-pill);
  background-color: var(--btn-bg);
  color: var(--btn-fg);
  font-family: var(--font-display);
  font-size: var(--text-sm);
  font-weight: var(--weight-medium);
  letter-spacing: 0.01em;
  white-space: nowrap;
  cursor: pointer;
  transition: background-color var(--duration-base) var(--ease-out),
    border-color var(--duration-base) var(--ease-out),
    color var(--duration-base) var(--ease-out),
    transform var(--duration-fast) var(--ease-out),
    box-shadow var(--duration-base) var(--ease-out);
}

.btn:active {
  transform: scale(0.975);
}

.btn__icon {
  display: inline-flex;
  transition: transform var(--duration-base) var(--ease-out);
}

.btn:hover .btn__icon {
  transform: translateX(4px);
}

.btn--primary {
  --btn-bg: var(--btn-primary-bg);
  --btn-fg: var(--btn-primary-fg);
  --btn-border: var(--btn-primary-bg);
  box-shadow: var(--shadow-sm);
}

.btn--primary:hover {
  --btn-bg: var(--btn-primary-bg-hover);
  --btn-border: var(--btn-primary-bg-hover);
  box-shadow: var(--shadow-md);
}

.btn--secondary {
  --btn-bg: transparent;
  --btn-fg: var(--text-strong);
  --btn-border: var(--border-strong);
}

.btn--secondary:hover {
  --btn-border: var(--accent-strong);
  --btn-fg: var(--accent-strong);
  background-color: var(--accent-wash);
}

.btn--ghost {
  --btn-border: transparent;
  padding-inline: var(--space-3);
}

.btn--ghost:hover {
  --btn-fg: var(--accent-strong);
}

.btn--block {
  width: 100%;
}

.btn--sm {
  min-height: 2.375rem;
  padding: var(--space-2) var(--space-5);
  font-size: var(--text-xs);
}

/* Text link with an underline that draws in on hover */
.link-underline {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  color: var(--accent-strong);
  font-family: var(--font-display);
  font-size: var(--text-sm);
  font-weight: var(--weight-medium);
}

.link-underline::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -2px;
  width: 100%;
  height: 1px;
  background-color: currentColor;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--duration-base) var(--ease-out);
}

.link-underline:hover::after,
.link-underline:focus-visible::after {
  transform: scaleX(1);
}

.link-underline svg,
.link-underline .icon {
  transition: transform var(--duration-base) var(--ease-out);
}

.link-underline:hover svg,
.link-underline:hover .icon {
  transform: translateX(4px);
}

/* --------------------------------------------------------------------------
   Surfaces
   -------------------------------------------------------------------------- */

.panel {
  position: relative;
  border: var(--border-width) solid var(--border);
  border-radius: var(--radius-lg);
  background-color: var(--surface);
  transition: border-color var(--duration-base) var(--ease-out),
    background-color var(--duration-base) var(--ease-out),
    box-shadow var(--duration-base) var(--ease-out),
    transform var(--duration-base) var(--ease-out);
}

.panel--raised {
  background-color: var(--surface-raised);
  box-shadow: var(--shadow-sm);
}

.panel--interactive:hover {
  transform: translateY(-6px);
  border-color: var(--border-strong);
  box-shadow: var(--shadow-lg);
}

.panel--pad {
  padding: var(--space-8);
}

/* Small technical corner brackets, used on featured surfaces */
.bracketed::before,
.bracketed::after {
  content: "";
  position: absolute;
  width: 14px;
  height: 14px;
  border-color: var(--accent-strong);
  opacity: 0;
  transition: opacity var(--duration-base) var(--ease-out);
  pointer-events: none;
}

.bracketed::before {
  top: 10px;
  left: 10px;
  border-top: 1.5px solid;
  border-left: 1.5px solid;
}

.bracketed::after {
  bottom: 10px;
  right: 10px;
  border-bottom: 1.5px solid;
  border-right: 1.5px solid;
}

.bracketed:hover::before,
.bracketed:hover::after {
  opacity: 0.8;
}

/* Badges and chips */
.chip {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-1) var(--space-3);
  border: var(--border-width) solid var(--border);
  border-radius: var(--radius-pill);
  background-color: var(--surface-sunken);
  font-family: var(--font-display);
  font-size: var(--text-xs);
  font-weight: var(--weight-medium);
  letter-spacing: 0.02em;
  color: var(--text-secondary);
  white-space: nowrap;
}

.chip--accent {
  border-color: var(--accent-border);
  background-color: var(--accent-wash);
  color: var(--accent-strong);
}

.chip--status {
  text-transform: uppercase;
  letter-spacing: var(--tracking-wide);
  font-size: var(--text-2xs);
}

.chip__dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background-color: var(--accent-strong);
  flex: none;
}

/* Icons rendered from an SVG file, masked so they inherit the text colour */
.icon-mask {
  display: inline-block;
  width: 1em;
  height: 1em;
  background-color: currentColor;
  -webkit-mask-position: center;
  mask-position: center;
  -webkit-mask-repeat: no-repeat;
  mask-repeat: no-repeat;
  -webkit-mask-size: contain;
  mask-size: contain;
  flex: none;
}

/* --------------------------------------------------------------------------
   Scroll reveal
   Elements start shifted and transparent, then settle when observed. The
   no-js and reduced-motion cases both fall back to fully visible.
   -------------------------------------------------------------------------- */

[data-reveal] {
  opacity: 0;
  transform: translateY(22px);
  transition: opacity var(--duration-slow) var(--ease-out),
    transform var(--duration-slow) var(--ease-out);
  transition-delay: var(--reveal-delay, 0ms);
}

[data-reveal].is-revealed {
  opacity: 1;
  transform: none;
}

html.no-js [data-reveal] {
  opacity: 1;
  transform: none;
}

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

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

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

  [data-reveal] {
    opacity: 1;
    transform: none;
  }

  .panel--interactive:hover {
    transform: none;
  }

  .btn:active {
    transform: none;
  }
}