/* ─────────────────────────────────────────────────────────────
   WA Pair Code — visual system

   Tokens and rationale live in DESIGN.md. Short version:
   near-black canvas, charcoal surface ladder, hairline borders,
   one emerald accent that only ever marks interaction or success.
   ───────────────────────────────────────────────────────────── */

:root {
  /* surfaces */
  --canvas: #08090a;
  --canvas-raised: #0b0d0f;
  --surface-1: #101214;
  --surface-2: #15181b;
  --surface-3: #1b1f23;

  /* lines & text */
  --hairline: rgba(255, 255, 255, 0.07);
  --hairline-strong: rgba(255, 255, 255, 0.13);
  --ink: #f4f6f7;
  --ink-muted: #a6aeb6;
  --ink-subtle: #8a9299; /* 6.0:1 on surface-1, 5.5:1 on canvas */
  --ink-disabled: #4a5158;

  /* accent */
  --accent: #2ee59d;
  --accent-hover: #4df0b0;
  --accent-pressed: #1fcb8a;
  --on-accent: #04140d;
  --accent-soft: rgba(46, 229, 157, 0.12);
  --accent-soft-solid: #142b24; /* accent-soft composited over surface-1 */
  --accent-ring: rgba(46, 229, 157, 0.18);

  /* semantic */
  --danger: #ff7a7a;
  --danger-soft: rgba(255, 122, 122, 0.12);
  --danger-soft-solid: #2d1e20; /* danger-soft composited over surface-1 */

  /* shape */
  --r-xs: 6px;
  --r-sm: 8px;
  --r-md: 10px;
  --r-lg: 14px;
  --r-xl: 18px;
  --r-pill: 9999px;

  /* type */
  --font-sans: Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue",
    Arial, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, "SF Mono", "Cascadia Code", Consolas, monospace;

  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

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

html {
  color-scheme: dark;
}

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background: var(--canvas);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 15px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ── Background ────────────────────────────────────────────── */
.backdrop {
  position: fixed;
  inset: 0;
  z-index: -1;
  background:
    radial-gradient(880px 520px at 16% -10%, rgba(46, 229, 157, 0.08), transparent 62%),
    radial-gradient(760px 480px at 92% 4%, rgba(122, 184, 255, 0.055), transparent 64%),
    var(--canvas);
}

.backdrop::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, rgba(255, 255, 255, 0.026) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(255, 255, 255, 0.026) 1px, transparent 1px);
  background-size: 64px 64px;
  -webkit-mask-image: radial-gradient(1100px 680px at 50% -4%, #000 0%, transparent 76%);
  mask-image: radial-gradient(1100px 680px at 50% -4%, #000 0%, transparent 76%);
}

/* ── Top bar ───────────────────────────────────────────────── */
.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 14px clamp(18px, 4vw, 40px);
  border-bottom: 1px solid var(--hairline);
  background: rgba(8, 9, 10, 0.72);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  text-decoration: none;
}

.brand__mark {
  width: 32px;
  height: 32px;
  display: grid;
  place-items: center;
  border-radius: 9px;
  border: 1px solid var(--hairline-strong);
  background: linear-gradient(180deg, var(--surface-3), var(--surface-1));
  color: var(--accent);
}

.brand__mark svg {
  width: 17px;
  height: 17px;
}

.brand__text {
  display: grid;
  line-height: 1.15;
}

.brand__text strong {
  font-size: 13.5px;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.brand__text span {
  font-size: 10px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-subtle);
}

.topbar__links {
  display: flex;
  align-items: center;
  gap: 4px;
}

.navlink {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 7px 10px;
  border: 1px solid transparent;
  border-radius: var(--r-sm);
  background: none;
  color: var(--ink-muted);
  font: inherit;
  font-size: 12.5px;
  font-weight: 500;
  text-decoration: none;
  cursor: pointer;
  transition: color 0.16s, background 0.16s, border-color 0.16s;
}

.navlink svg {
  width: 12px;
  height: 12px;
  opacity: 0.7;
}

.navlink:hover {
  color: var(--ink);
  background: var(--surface-2);
  border-color: var(--hairline);
}

.navlink:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* ── Shell ─────────────────────────────────────────────────── */
.shell {
  flex: 1;
  width: 100%;
  max-width: 1080px;
  margin: 0 auto;
  padding: clamp(40px, 8vh, 88px) clamp(18px, 4vw, 40px) 48px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 404px;
  gap: clamp(32px, 5vw, 76px);
  align-items: center;
}

/* ── Hero ──────────────────────────────────────────────────── */
.hero {
  max-width: 520px;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin: 0 0 22px;
  font-size: 10.5px;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent);
}

.eyebrow__dot {
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 4px var(--accent-soft);
  animation: pulse 2.4s ease-in-out infinite;
}

@keyframes pulse {
  0%,
  100% {
    opacity: 1;
    box-shadow: 0 0 0 4px var(--accent-soft);
  }
  50% {
    opacity: 0.65;
    box-shadow: 0 0 0 7px rgba(46, 229, 157, 0.04);
  }
}

h1 {
  margin: 0 0 18px;
  font-size: clamp(2.1rem, 4vw, 3.1rem);
  font-weight: 600;
  line-height: 1.04;
  letter-spacing: -0.04em;
}

.grad {
  background: linear-gradient(100deg, #f4f6f7 6%, #9df4d2 52%, var(--accent) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero__lede {
  margin: 0 0 30px;
  max-width: 46ch;
  color: var(--ink-muted);
  font-size: 15px;
  line-height: 1.65;
}

.features {
  list-style: none;
  margin: 0 0 30px;
  padding: 0;
  display: grid;
  gap: 16px;
}

.features li {
  display: flex;
  align-items: flex-start;
  gap: 12px;
}

.features__icon {
  flex: none;
  width: 28px;
  height: 28px;
  display: grid;
  place-items: center;
  border-radius: var(--r-sm);
  border: 1px solid var(--hairline);
  background: var(--surface-1);
  color: var(--accent);
}

.features__icon svg {
  width: 13px;
  height: 13px;
}

.features b {
  display: block;
  font-size: 13.5px;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.features span {
  font-size: 12.5px;
  color: var(--ink-subtle);
}

.features code,
.success code {
  font-family: var(--font-mono);
  font-size: 11.5px;
  padding: 1px 5px;
  border-radius: 5px;
  background: rgba(0, 0, 0, 0.32);
  color: var(--ink-muted);
}

.hero__foot {
  margin: 0;
  padding-left: 12px;
  border-left: 2px solid var(--hairline-strong);
  font-size: 12px;
  line-height: 1.65;
  color: var(--ink-subtle);
}

/* ── Card ──────────────────────────────────────────────────── */
.card {
  position: relative;
  padding: 24px;
  border: 1px solid var(--hairline);
  border-radius: var(--r-xl);
  background: linear-gradient(180deg, #131619 0%, var(--surface-1) 100%);
  box-shadow:
    0 40px 80px -32px rgba(0, 0, 0, 0.85),
    inset 0 1px 0 rgba(255, 255, 255, 0.05);
}

.card__head {
  margin-bottom: 18px;
}

.card__head h2 {
  margin: 0 0 3px;
  font-size: 17px;
  font-weight: 600;
  letter-spacing: -0.02em;
}

.card__head p {
  margin: 0;
  font-size: 12.5px;
  color: var(--ink-subtle);
}

/* ── Segmented control ─────────────────────────────────────── */
.segmented {
  position: relative;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4px;
  padding: 4px;
  margin-bottom: 20px;
  border: 1px solid var(--hairline);
  border-radius: 12px;
  background: var(--canvas-raised);
}

.segmented__thumb {
  position: absolute;
  top: 4px;
  left: 4px;
  width: calc(50% - 6px);
  height: 34px;
  border-radius: var(--r-sm);
  border: 1px solid var(--hairline-strong);
  background: linear-gradient(180deg, var(--surface-3), var(--surface-2));
  box-shadow: 0 1px 0 rgba(255, 255, 255, 0.04) inset;
  transition: transform 0.22s var(--ease);
}

.segmented[data-mode="qr"] .segmented__thumb {
  transform: translateX(calc(100% + 4px));
}

.segmented__btn {
  position: relative;
  z-index: 1;
  height: 34px;
  border: 0;
  border-radius: var(--r-sm);
  background: none;
  color: var(--ink-muted); /* 8.7:1 on canvas-raised — AA at this size */
  font: inherit;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  transition: color 0.18s;
}

.segmented__btn.is-active {
  color: var(--ink);
}

.segmented__btn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

.segmented__btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

/* ── Form ──────────────────────────────────────────────────── */
.panel {
  display: grid;
  gap: 14px;
}

.panel__note {
  margin: 0;
  padding: 12px 14px;
  border: 1px dashed var(--hairline-strong);
  border-radius: var(--r-md);
  color: var(--ink-subtle);
  font-size: 12.5px;
  line-height: 1.6;
}

.field {
  display: grid;
  gap: 7px;
}

.field__label {
  font-size: 11.5px;
  font-weight: 500;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--ink-muted);
}

.field__control {
  display: flex;
  align-items: center;
  height: 48px;
  border: 1px solid var(--hairline-strong);
  border-radius: var(--r-md);
  background: var(--canvas-raised);
  transition: border-color 0.18s, box-shadow 0.18s;
}

.field__control:focus-within {
  border-color: rgba(46, 229, 157, 0.5);
  box-shadow: 0 0 0 3px var(--accent-ring);
}

.field__prefix {
  padding-left: 14px;
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--ink-subtle);
}

.field__input {
  flex: 1;
  min-width: 0;
  height: 100%;
  padding: 0 14px 0 7px;
  border: 0;
  background: none;
  color: var(--ink);
  font: inherit;
  font-size: 15px;
  letter-spacing: 0.01em;
  outline: none;
}

.field__input::placeholder {
  color: var(--ink-disabled);
}

.field__hint {
  font-size: 11.5px;
  color: var(--ink-subtle);
}

/* ── Buttons ───────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  width: 100%;
  height: 48px;
  padding: 0 18px;
  border: 1px solid transparent;
  border-radius: var(--r-md);
  font: inherit;
  font-size: 14px;
  font-weight: 600;
  letter-spacing: -0.01em;
  text-decoration: none;
  cursor: pointer;
  transition: background 0.16s, border-color 0.16s, transform 0.06s, opacity 0.16s;
}

.btn--primary {
  background: var(--accent);
  color: var(--on-accent);
  box-shadow: 0 10px 30px -14px rgba(46, 229, 157, 0.55);
}

.btn--primary:hover {
  background: var(--accent-hover);
}

.btn--primary:active {
  background: var(--accent-pressed);
  transform: translateY(1px);
}

.btn--ghost {
  height: 44px;
  background: var(--surface-2);
  border-color: var(--hairline);
  color: var(--ink);
}

.btn--ghost:hover {
  background: var(--surface-3);
}

.btn:disabled {
  opacity: 0.45;
  cursor: progress;
  transform: none;
  box-shadow: none;
}

.btn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* ── Result ────────────────────────────────────────────────── */
.result {
  display: grid;
  gap: 14px;
  margin-top: 20px;
  animation: rise 0.28s var(--ease);
}

@keyframes rise {
  from {
    opacity: 0;
    transform: translateY(6px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

.result__bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border: 1px solid var(--hairline);
  border-radius: var(--r-pill);
  background: var(--surface-2);
  color: var(--ink-muted);
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.badge.is-live {
  background: var(--accent-soft-solid);
  border-color: rgba(46, 229, 157, 0.26);
  color: var(--accent);
}

.badge.is-error {
  background: var(--danger-soft-solid);
  border-color: rgba(255, 122, 122, 0.28);
  color: var(--danger);
}

.countdown {
  font-family: var(--font-mono);
  font-size: 12px;
  font-variant-numeric: tabular-nums;
  color: var(--ink-subtle);
}

.countdown.is-warn {
  color: var(--danger);
}

/* Code readout */
.code {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px 46px;
  border: 1px solid var(--hairline);
  border-radius: var(--r-lg);
  background: var(--canvas-raised);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.045);
}

.code code {
  font-family: var(--font-mono);
  font-size: clamp(23px, 4.4vw, 30px);
  font-weight: 600;
  letter-spacing: 0.16em;
  color: var(--ink);
  text-shadow: 0 0 26px rgba(46, 229, 157, 0.16);
  word-break: break-all;
  text-align: center;
}

.icon-btn {
  position: absolute;
  top: 8px;
  right: 8px;
  width: 30px;
  height: 30px;
  display: grid;
  place-items: center;
  border: 1px solid transparent;
  border-radius: var(--r-xs);
  background: none;
  color: var(--ink-subtle);
  cursor: pointer;
  transition: color 0.16s, background 0.16s, border-color 0.16s;
}

.icon-btn svg {
  width: 14px;
  height: 14px;
}

.icon-btn:hover {
  color: var(--ink);
  background: var(--surface-2);
  border-color: var(--hairline);
}

.icon-btn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

/* QR */
.qr {
  display: grid;
  place-items: center;
  padding: 12px;
  border: 1px solid var(--hairline);
  border-radius: var(--r-lg);
  background: #fff;
}

.qr img {
  display: block;
  width: 100%;
  max-width: 280px;
  height: auto;
  border-radius: 4px;
  image-rendering: pixelated;
}

/* Progress rail */
.progress {
  height: 4px;
  overflow: hidden;
  border-radius: var(--r-pill);
  background: rgba(255, 255, 255, 0.09);
}

.progress__fill {
  display: block;
  width: 100%;
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--accent-pressed), var(--accent));
  transition: width 1s linear, background 0.3s;
}

.progress__fill.is-warn {
  background: var(--danger);
}

/* Steps */
.steps {
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: step;
  display: grid;
  gap: 9px;
}

.steps li {
  display: flex;
  align-items: baseline;
  gap: 10px;
  font-size: 12.5px;
  line-height: 1.5;
  color: var(--ink-muted);
}

.steps li::before {
  counter-increment: step;
  content: counter(step);
  flex: none;
  width: 19px;
  height: 19px;
  display: grid;
  place-items: center;
  border: 1px solid var(--hairline-strong);
  border-radius: 50%;
  font-family: var(--font-mono);
  font-size: 9.5px;
  color: var(--ink-subtle);
  transform: translateY(2px);
}

.steps li:first-child::before {
  border-color: rgba(46, 229, 157, 0.4);
  color: var(--accent);
}

.steps b {
  color: var(--ink);
  font-weight: 600;
}

/* ── Success ───────────────────────────────────────────────── */
.success {
  display: grid;
  justify-items: center;
  gap: 9px;
  margin-top: 20px;
  padding: 22px 18px;
  border: 1px solid rgba(46, 229, 157, 0.26);
  border-radius: var(--r-lg);
  background: linear-gradient(180deg, rgba(46, 229, 157, 0.1), rgba(46, 229, 157, 0.025));
  text-align: center;
  animation: rise 0.28s var(--ease);
}

.success__icon {
  width: 38px;
  height: 38px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: var(--accent);
  color: var(--on-accent);
}

.success__icon svg {
  width: 18px;
  height: 18px;
}

.success__title {
  margin: 0;
  font-size: 16px;
  font-weight: 600;
  letter-spacing: -0.02em;
}

.success__text {
  margin: 0 0 4px;
  max-width: 32ch;
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--ink-muted);
}

/* ── Alert ─────────────────────────────────────────────────── */
.alert {
  display: flex;
  gap: 9px;
  align-items: flex-start;
  margin-top: 16px;
  padding: 11px 13px;
  border: 1px solid rgba(255, 122, 122, 0.26);
  border-radius: var(--r-md);
  background: var(--danger-soft-solid);
  color: var(--danger);
  font-size: 12.5px;
  line-height: 1.55;
  animation: rise 0.2s var(--ease);
}

.alert::before {
  content: "!";
  flex: none;
  width: 16px;
  height: 16px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: var(--danger);
  color: #1a0505;
  font-size: 10px;
  font-weight: 700;
  transform: translateY(1px);
}

/* ── Card foot ─────────────────────────────────────────────── */
.card__foot {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-top: 20px;
  padding-top: 14px;
  border-top: 1px solid var(--hairline);
  font-size: 11px;
  color: var(--ink-subtle);
}

.pulse {
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

/* ── Page footer ───────────────────────────────────────────── */
.site-foot {
  display: flex;
  justify-content: center;
  gap: 8px;
  padding: 18px;
  font-size: 11.5px;
  color: var(--ink-subtle);
}

/* ── Toast ─────────────────────────────────────────────────── */
.toast {
  position: fixed;
  left: 50%;
  bottom: 26px;
  z-index: 60;
  padding: 10px 16px;
  border: 1px solid var(--hairline-strong);
  border-radius: var(--r-md);
  background: var(--surface-3);
  color: var(--ink);
  font-size: 12.5px;
  font-weight: 500;
  box-shadow: 0 24px 50px -24px rgba(0, 0, 0, 0.9);
  opacity: 0;
  transform: translate(-50%, 10px);
  pointer-events: none;
  transition: opacity 0.2s, transform 0.2s var(--ease);
}

.toast.is-visible {
  opacity: 1;
  transform: translate(-50%, 0);
}

/* ── Dialog ────────────────────────────────────────────────── */
.dialog {
  width: min(430px, calc(100% - 32px));
  padding: 22px;
  border: 1px solid var(--hairline-strong);
  border-radius: var(--r-xl);
  background: var(--surface-1);
  color: var(--ink);
  box-shadow: 0 40px 90px -30px rgba(0, 0, 0, 0.95);
}

.dialog::backdrop {
  background: rgba(0, 0, 0, 0.62);
  backdrop-filter: blur(3px);
}

.dialog h2 {
  margin: 0 0 4px;
  font-size: 15px;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.dialog__sub {
  margin: 0;
  font-size: 12px;
  color: var(--ink-subtle);
}

.api-list {
  display: grid;
  gap: 2px;
  margin: 16px 0;
  font-size: 12px;
}

.api-list dt {
  margin-top: 12px;
}

.api-list dt code {
  padding: 3px 7px;
  border: 1px solid var(--hairline);
  border-radius: var(--r-xs);
  background: var(--canvas-raised);
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--ink);
}

.api-list dd {
  margin: 4px 0 0;
  color: var(--ink-subtle);
  line-height: 1.55;
}

.api-list dd code {
  padding: 1px 4px;
  border-radius: 4px;
  background: rgba(255, 255, 255, 0.05);
  font-family: var(--font-mono);
  font-size: 10.5px;
}

/* ── Utilities ─────────────────────────────────────────────── */
.is-hidden {
  display: none !important;
}

/* ── Responsive ────────────────────────────────────────────── */
@media (max-width: 900px) {
  .shell {
    grid-template-columns: minmax(0, 1fr);
    justify-items: center;
    max-width: 460px;
    padding-top: 32px;
  }

  .hero {
    display: none;
  }

  .card {
    width: 100%;
  }
}

@media (max-width: 420px) {
  .card {
    padding: 20px 18px;
    border-radius: var(--r-lg);
  }

  .code {
    padding: 20px 40px;
  }

  .brand__text span {
    display: none;
  }
}

/* ── Motion preferences ────────────────────────────────────── */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}