/* ===========================================================================
   depth2normal.cobanov.dev

   One page, one job: a depth map goes in and a normal map comes out, in the
   visitor's own tab.

   The accent is not a brand colour, it is the subject. A surface facing the
   camera encodes as rgb(128, 128, 255), so every normal map is mostly this
   lavender; the page borrows it and spends it in one place, on the things you
   can act on. Everything else is film-base black and grey, so the two images
   are the only colour on the screen.

   Type is Geist for reading and JetBrains Mono for anything measured: pixel
   counts, milliseconds, file sizes, option names. If it is a number, it is
   mono.
   =========================================================================== */

:root {
  color-scheme: dark;

  --base: #0c0c0e;
  --surface: #141417;
  --surface-2: #1c1c21;
  --ink: #ecedf1;
  --muted: #8b8d99;
  --line: rgba(236, 237, 241, 0.09);
  --line-strong: rgba(236, 237, 241, 0.2);

  /* rgb(128, 128, 255) is a normal pointing at you. This is that, lifted just
     enough to clear 7:1 against the base. */
  --accent: #9d9dff;
  --accent-hover: #b8b8ff;
  --accent-quiet: rgba(157, 157, 255, 0.12);
  --on-accent: #0c0c0e;

  --sans: Geist, ui-sans-serif, system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;

  /* One base-8 scale for every gap, margin and pad. */
  --s-1: 4px;
  --s-2: 8px;
  --s-3: 12px;
  --s-4: 16px;
  --s-5: 24px;
  --s-6: 32px;
  --s-7: 48px;
  --s-8: 64px;

  --t-caption: 0.75rem;
  --t-small: 0.8125rem;
  --t-body: 1rem;
  --t-lead: clamp(1rem, 0.95rem + 0.35vw, 1.125rem);
  --t-title: clamp(1.35rem, 1.1rem + 1vw, 1.75rem);
  --t-display: clamp(2rem, 1.3rem + 3.2vw, 3.25rem);

  --measure: 1080px;
  --prose: 60ch;
  --gutter: clamp(20px, 5vw, 56px);

  --radius: 12px;
  --radius-sm: 8px;
  --pill: 999px;
  --ease: cubic-bezier(0.16, 1, 0.3, 1);
}

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

/* The controls are display:grid, which would otherwise win over [hidden]. */
[hidden] {
  display: none !important;
}

html {
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100dvh;
  background: var(--base);
  color: var(--ink);
  font-family: var(--sans);
  font-size: var(--t-body);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

@media (prefers-reduced-motion: reduce) {
  * {
    animation: none !important;
    transition: none !important;
  }
}

/* Film grain: fixed, so it sits in front of the page rather than scrolling
   with it, and far too faint to notice until it is removed. */
body::after {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 60;
  pointer-events: none;
  opacity: 0.03;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='140' height='140'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='3'/%3E%3C/filter%3E%3Crect width='140' height='140' filter='url(%23n)'/%3E%3C/svg%3E");
}

h1,
h2 {
  margin: 0;
  line-height: 1.1;
  letter-spacing: -0.03em;
  text-wrap: balance;
}

p {
  text-wrap: pretty;
}

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

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

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}

code,
kbd {
  font-family: var(--mono);
  font-size: 0.9em;
}

.mono {
  font-family: var(--mono);
  font-variant-numeric: tabular-nums;
}

.shell {
  width: min(var(--measure), 100% - var(--gutter) * 2);
  margin-inline: auto;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 100;
  padding: var(--s-3) var(--s-4);
  background: var(--accent);
  color: var(--on-accent);
  border-radius: 0 0 var(--radius-sm) 0;
  font-weight: 600;
}

.skip-link:focus {
  left: 0;
}

/* --- masthead ------------------------------------------------------------ */

.masthead {
  position: sticky;
  top: 0;
  z-index: 20;
  background: color-mix(in srgb, var(--base) 86%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}

.masthead-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--s-4);
  min-height: 56px;
}

.wordmark {
  display: inline-flex;
  align-items: center;
  gap: var(--s-2);
  color: var(--ink);
  font-family: var(--mono);
  font-weight: 500;
  letter-spacing: -0.02em;
}

.wordmark:hover {
  text-decoration: none;
}

/* The mark is a normal map of a sphere in miniature: the same lavender the
   page runs on, lit from the upper left. */
.wordmark-mark {
  width: 18px;
  height: 18px;
  border-radius: 5px;
  background:
    radial-gradient(circle at 30% 28%, #d7ffbe 0%, #8c8cff 46%, #5b5bd6 78%, #3a3aa8 100%);
}

.masthead nav {
  display: flex;
  align-items: center;
  gap: var(--s-4);
  font-size: var(--t-small);
}

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

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

.install {
  font-family: var(--mono);
  font-size: var(--t-caption);
  color: var(--muted);
  border: 1px solid var(--line);
  border-radius: var(--pill);
  padding: 4px 12px;
  white-space: nowrap;
}

@media (max-width: 640px) {
  .install {
    display: none;
  }
}

/* --- hero ---------------------------------------------------------------- */

.hero {
  padding-block: clamp(var(--s-7), 7vw, 88px) var(--s-6);
}

.hero h1 {
  font-size: var(--t-display);
  max-width: 18ch;
}

.hero .lead {
  margin: var(--s-5) 0 0;
  max-width: var(--prose);
  color: var(--muted);
  font-size: var(--t-lead);
}

.hero .lead strong {
  color: var(--ink);
  font-weight: 500;
}

/* --- stage --------------------------------------------------------------- */

.stage {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--s-4);
}

.stage.empty {
  grid-template-columns: 1fr;
}

.stage.empty .panel {
  display: none;
}

.stage:not(.empty) .dropzone {
  display: none;
}

.dropzone {
  border: 1px dashed var(--line-strong);
  border-radius: var(--radius);
  padding: clamp(var(--s-7), 9vw, 96px) var(--s-5);
  text-align: center;
  transition: border-color 0.2s var(--ease), background 0.2s var(--ease);
}

.dropzone.over {
  border-color: var(--accent);
  background: var(--accent-quiet);
}

.dropzone h2 {
  font-size: var(--t-title);
  font-weight: 500;
}

.dropzone p {
  margin: var(--s-3) 0 0;
  color: var(--muted);
  font-size: var(--t-small);
}

.panel {
  margin: 0;
  min-width: 0;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--s-3);
  display: grid;
  gap: var(--s-3);
}

.panel figcaption {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--s-3);
  font-family: var(--mono);
  font-size: var(--t-caption);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--muted);
}

.panel figcaption .value {
  color: var(--accent);
  text-transform: none;
  letter-spacing: 0;
}

canvas {
  display: block;
  width: 100%;
  height: auto;
  max-height: 60vh;
  object-fit: contain;
  border-radius: var(--radius-sm);
  background: transparent;
}

/* --- controls ------------------------------------------------------------ */

.controls {
  margin-top: var(--s-4);
  padding: var(--s-5);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: var(--s-5);
  align-items: end;
}

.field {
  display: grid;
  gap: var(--s-2);
  min-width: 0;
}

.field > .label {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: var(--s-2);
  font-family: var(--mono);
  font-size: var(--t-caption);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
}

.field .label output {
  color: var(--accent);
  text-transform: none;
  letter-spacing: 0;
}

select {
  width: 100%;
  font: inherit;
  font-size: var(--t-small);
  color: var(--ink);
  background: var(--surface-2);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 9px 10px;
}

select:hover {
  border-color: var(--line-strong);
}

/* A slider that looks like the rest of the page rather than like the OS. */
input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 22px;
  background: transparent;
  cursor: pointer;
}

input[type="range"]::-webkit-slider-runnable-track {
  height: 3px;
  border-radius: 2px;
  background: var(--line-strong);
}

input[type="range"]::-moz-range-track {
  height: 3px;
  border-radius: 2px;
  background: var(--line-strong);
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 14px;
  height: 14px;
  margin-top: -5.5px;
  border-radius: 50%;
  background: var(--accent);
}

input[type="range"]::-moz-range-thumb {
  width: 14px;
  height: 14px;
  border: 0;
  border-radius: 50%;
  background: var(--accent);
}

.toggle {
  display: flex;
  align-items: center;
  gap: var(--s-2);
  font-size: var(--t-small);
  color: var(--muted);
  cursor: pointer;
}

.toggle input {
  accent-color: var(--accent);
  width: 15px;
  height: 15px;
}

.actions {
  grid-column: 1 / -1;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--s-3);
  padding-top: var(--s-1);
  border-top: 1px solid var(--line);
}

button {
  font-family: var(--mono);
  font-size: var(--t-small);
  color: var(--ink);
  background: var(--surface-2);
  border: 1px solid var(--line);
  border-radius: var(--pill);
  padding: 8px 16px;
  cursor: pointer;
  transition: border-color 0.15s var(--ease), color 0.15s var(--ease);
}

button:hover:not(:disabled) {
  border-color: var(--accent);
  color: var(--accent);
}

button:disabled {
  opacity: 0.45;
  cursor: default;
}

button.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--on-accent);
  font-weight: 600;
}

button.primary:hover:not(:disabled) {
  background: var(--accent-hover);
  border-color: var(--accent-hover);
  color: var(--on-accent);
}

button.quiet {
  background: none;
  border-color: transparent;
  color: var(--muted);
  padding-inline: var(--s-2);
}

.link-button {
  background: none;
  border: 0;
  padding: 0;
  font: inherit;
  color: var(--accent);
  cursor: pointer;
  text-decoration: underline;
  text-underline-offset: 3px;
}

.status {
  margin: var(--s-4) auto 0;
  min-height: 1.6em;
  font-family: var(--mono);
  font-size: var(--t-small);
  color: var(--muted);
}

.status[data-busy="true"]::after {
  content: "";
  display: inline-block;
  width: 6px;
  height: 6px;
  margin-left: 8px;
  border-radius: 50%;
  background: var(--accent);
  animation: pulse 1s var(--ease) infinite;
  vertical-align: middle;
}

@keyframes pulse {
  0%, 100% { opacity: 0.25; }
  50% { opacity: 1; }
}

/* --- notes --------------------------------------------------------------- */

.notes {
  padding-block: clamp(var(--s-7), 8vw, 96px) var(--s-6);
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: var(--s-6);
}

.note h2 {
  font-size: var(--t-caption);
  font-family: var(--mono);
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
}

.note p {
  margin: var(--s-3) 0 0;
  color: var(--muted);
  font-size: var(--t-small);
  max-width: 46ch;
}

.note code {
  color: var(--ink);
}

/* --- footer -------------------------------------------------------------- */

footer {
  border-top: 1px solid var(--line);
  padding-block: var(--s-6) var(--s-8);
}

footer .shell {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: var(--s-4);
  font-size: var(--t-small);
  color: var(--muted);
}

@media (max-width: 720px) {
  .stage {
    grid-template-columns: 1fr;
  }

  .controls {
    padding: var(--s-4);
    gap: var(--s-4);
  }
}