/* ==========================================================================
   style.css — the foundation: fonts, colours, spacing, motion, page basics.
   Change a value in :root and it updates everywhere on the site.
   ========================================================================== */

/* ----- Fonts (self-hosted, so visitors never contact a third party) ----- */
@font-face {
  font-family: "Geist";
  src: url("../fonts/geist-latin-wght-normal.woff2") format("woff2");
  font-weight: 100 900;               /* one variable file covers every weight */
  font-style: normal;
  font-display: swap;                 /* show text immediately, swap when loaded */
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA,
    U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193,
    U+2212, U+2215, U+FEFF, U+FFFD;
}

@font-face {
  font-family: "Geist Mono";
  src: url("../fonts/geist-mono-latin-wght-normal.woff2") format("woff2");
  font-weight: 100 900;
  font-style: normal;
  font-display: swap;
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA,
    U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193,
    U+2212, U+2215, U+FEFF, U+FFFD;
}

:root {
  color-scheme: dark;

  /* ----- Colour: surfaces (darkest to lightest) ----- */
  --bg: #09090d;
  --bg-section: #0e0e14;
  --surface-1: #13131a;               /* cards */
  --surface-2: #1a1a23;               /* inputs, hover, dropdowns */
  --surface-3: #22222d;               /* icon tiles, pressed states */

  /* ----- Colour: borders ----- */
  --border-subtle: rgba(255, 255, 255, 0.07);
  --border: rgba(255, 255, 255, 0.11);
  --border-strong: rgba(255, 255, 255, 0.20);

  /* ----- Colour: text ----- */
  --text-1: #f3f2f8;                  /* headings, key text */
  --text-2: #a8a6b8;                  /* body text */
  --text-3: #86849a;                  /* meta text. NOT for use on --surface-3 */

  /* ----- Colour: lime = actions and state only ----- */
  --lime: #b8ff6a;
  --lime-hover: #caff8c;
  --lime-tint: rgba(184, 255, 106, 0.12);
  --lime-border: rgba(184, 255, 106, 0.24);
  --on-lime: #0a0a0f;                 /* dark text on top of lime */

  /* ----- Colour: violet = quiet secondary accent ----- */
  --violet: #a58fff;
  --violet-text: #b9a8ff;
  --violet-tint: rgba(165, 143, 255, 0.12);
  --violet-border: rgba(165, 143, 255, 0.26);

  /* ----- Fonts ----- */
  --font-sans: "Geist", system-ui, -apple-system, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, sans-serif;
  --font-mono: "Geist Mono", ui-monospace, SFMono-Regular, Menlo, Consolas,
    monospace;

  /* ----- Spacing (4px base; 1rem = 16px) ----- */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.5rem;
  --space-6: 2rem;
  --space-7: 3rem;
  --space-8: 5rem;

  /* ----- Shape ----- */
  --radius-sm: 8px;                   /* chips, small controls */
  --radius-md: 10px;                  /* buttons, inputs */
  --radius-lg: 14px;                  /* cards, panels */
  --radius-xl: 20px;                  /* modals */

  /* ----- Layout ----- */
  --max-width: 75rem;                 /* 1200px */
  --gutter: clamp(1rem, 0.6rem + 1.6vw, 1.5rem);
  --header-height: 4rem;

  /* ----- Motion: one set of timings so everything feels consistent ----- */
  --dur-fast: 120ms;                  /* hover, press */
  --dur-base: 200ms;                  /* menus, panels */
  --dur-slow: 420ms;                  /* entrances */
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

/* ----- Reset: removes surprising browser defaults ----- */
*,
*::before,
*::after {
  box-sizing: border-box;
}

[hidden] {
  display: none !important;
}

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-height) + 1rem);
}

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;             /* keeps the footer at the bottom */
  background-color: var(--bg);
  background-image: radial-gradient(
    60rem 26rem at 85% -10%,
    rgba(165, 143, 255, 0.13),
    transparent 65%
  );
  background-repeat: no-repeat;
  color: var(--text-1);
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

main {
  flex: 1;
}

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

::selection {
  background: rgba(165, 143, 255, 0.35);
  color: var(--text-1);
}

/* ----- Typography ----- */
h1,
h2,
h3 {
  margin: 0 0 var(--space-4);
  color: var(--text-1);
  font-weight: 600;
  line-height: 1.1;
}

h1 {
  font-size: clamp(2.25rem, 1.6rem + 3.6vw, 3.5rem);   /* 36px to 56px */
  letter-spacing: -0.035em;
  line-height: 1.05;
}

h2 {
  font-size: clamp(1.75rem, 1.3rem + 1.6vw, 2.25rem);  /* 28px to 36px */
  letter-spacing: -0.025em;
}

h3 {
  font-size: 1.1875rem;                                /* 19px */
  letter-spacing: -0.015em;
}

p {
  margin: 0 0 var(--space-4);
  color: var(--text-2);
}

a {
  color: var(--text-1);
  text-decoration-color: var(--border-strong);
  text-underline-offset: 0.2em;
  transition: color var(--dur-fast) ease, text-decoration-color var(--dur-fast) ease;
}

a:hover {
  text-decoration-color: var(--lime);
}

.lead {
  max-width: 40rem;
  font-size: 1.125rem;
}

.text-muted {
  color: var(--text-3);
}

/* Small uppercase monospace label — the site's "technical detail" */
.eyebrow {
  margin: 0 0 var(--space-3);
  color: var(--violet);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.muted-line {
  display: block;                     /* second sentence of a headline starts on its own line */
  color: var(--text-3);
}

/* ----- Layout helpers ----- */
.container {
  width: min(100% - 2 * var(--gutter), var(--max-width));
  margin-inline: auto;
}

.section {
  padding-block: clamp(2.5rem, 1.5rem + 4vw, 5rem);
}

/* ----- Accessibility helpers ----- */

/* Visible keyboard focus on everything clickable */
:focus-visible {
  outline: 2px solid var(--lime);
  outline-offset: 3px;
}

/* "Skip to content" link: hidden until a keyboard user tabs to it */
.skip-link {
  position: absolute;
  left: var(--space-4);
  top: -4rem;
  z-index: 100;
  padding: var(--space-3) var(--space-4);
  background: var(--lime);
  color: var(--on-lime);
  font-weight: 600;
  border-radius: var(--radius-sm);
  text-decoration: none;
}

.skip-link:focus {
  top: var(--space-3);
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

/* ----- Motion: entrance animations ----- */

/* One keyframe: fade in while rising 12px. */
@keyframes rise {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
}

/* .enter       = plays once on page load (use for content at the top of a page)
   .reveal-in   = plays once when scrolled into view (added by app.js)
   --i sets the order for staggered items (0, 1, 2 ...).
   "backwards" means the animation does not keep holding the element afterwards,
   so hover effects still work on it. */
.enter,
.reveal-in {
  animation: rise var(--dur-slow) var(--ease) backwards;
  animation-delay: calc(var(--i, 0) * 60ms);
}

/* Below-the-fold items wait invisibly until app.js reveals them */
.reveal-hidden {
  opacity: 0;
}

/* Cross-document View Transitions are intentionally disabled.
   Browser support and opt-in state vary; normal page navigation is more reliable. */

/* ----- Respect visitors who ask their device for less motion ----- */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation: none !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  .reveal-hidden {
    opacity: 1;
  }
}