/* ── Reset ────────────────────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

/* ── Design tokens ─────────────────────────────────────────────────────────── */
:root {
  --content-width: 980px;
  --gutter: 22px;
  --col-gap: 24px;   /* 12-column grid gap */
  --radius-pill: 980px;
  --radius-card: 12px;

  --c-bg: #000;
  --c-surface: #111;
  --c-border: rgba(255, 255, 255, 0.12);
  --c-border-focus: rgba(255, 255, 255, 0.55);
  --c-text: #f5f5f7;
  --c-subtext: #6e6e73;
  --c-placeholder: #48484a;
  --c-error: #ff453a;
  --c-success: #32d74b;

  --ease-out: cubic-bezier(0.25, 0.1, 0.25, 1);
  --dur-transition: 460ms;
  --dur-micro: 200ms;
}

/* ── Base ──────────────────────────────────────────────────────────────────── */
html { -webkit-font-smoothing: antialiased; }

body {
  background: var(--c-bg);
  color: var(--c-text);
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Helvetica Neue", Arial, sans-serif;
  font-size: 17px;
  line-height: 1.47059;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--gutter);
}

/* ── Content grid ──────────────────────────────────────────────────────────── */
/*
 * All text and interactive content lives inside this centered, 12-column grid.
 * Column fractions: full = 1/-1, 2/3 = cols 3–11, 1/2 = cols 4–10, narrow = cols 5–9.
 */
.container {
  width: 100%;
  max-width: var(--content-width);
  margin-inline: auto;
  padding-inline: var(--gutter);
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  column-gap: var(--col-gap);
  justify-items: center;
  text-align: center;
}

/* ── Wordmark — full width ─────────────────────────────────────────────────── */
.wordmark {
  grid-column: 1 / -1;
  font-size: 0.8125rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--c-subtext);
  margin-bottom: 4.5rem;
  user-select: none;
}

/* ── Headline — 8 of 12 cols, centered ────────────────────────────────────── */
h1 {
  grid-column: 3 / 11;
  font-size: clamp(2.25rem, 5.5vw, 3.5rem);
  font-weight: 600;
  letter-spacing: -0.022em;
  line-height: 1.07;
  margin-bottom: 1rem;
}

/* ── Subtitle — 6 of 12 cols, centered; ~50–75ch line length ──────────────── */
.subtitle {
  grid-column: 4 / 10;
  font-size: clamp(0.9375rem, 1.8vw, 1.0625rem);
  color: var(--c-subtext);
  max-width: 46ch;
  margin-bottom: 3rem;
  line-height: 1.6;
}

/* ── Login card — 6 of 12 cols, centered ──────────────────────────────────── */
.login-card {
  grid-column: 4 / 10;
  width: 100%;
  max-width: 400px;
}

/* ── Step panels ────────────────────────────────────────────────────────────── */
.step {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.step[hidden] { display: none; }

/* Entrance: fade + slight upward slide, ease-out, ~460ms */
.step.entering {
  animation: step-in var(--dur-transition) var(--ease-out) forwards;
}

@keyframes step-in {
  from { opacity: 0; transform: translateY(10px); }
  to   { opacity: 1; transform: translateY(0); }
}

.step.exiting {
  animation: step-out var(--dur-transition) var(--ease-out) forwards;
}

@keyframes step-out {
  from { opacity: 1; transform: translateY(0); }
  to   { opacity: 0; transform: translateY(-8px); }
}

/* ── Inputs ─────────────────────────────────────────────────────────────────── */
.field {
  width: 100%;
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-pill); /* pill — matches buttons */
  color: var(--c-text);
  font-family: inherit;
  font-size: 1rem;
  padding: 0.7em 1.25em;
  outline: none;
  transition: border-color var(--dur-micro) var(--ease-out);
}

.field::placeholder { color: var(--c-placeholder); }
.field:focus { border-color: var(--c-border-focus); }

/* ── Buttons ────────────────────────────────────────────────────────────────── */
.btn {
  width: 100%;
  padding: 0.7em 1.25em;
  border-radius: var(--radius-pill); /* pill — same radius as .field */
  border: none;
  font-family: inherit;
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  transition:
    background var(--dur-micro) var(--ease-out),
    opacity var(--dur-micro) var(--ease-out),
    transform var(--dur-micro) var(--ease-out);
}

.btn:active { transform: scale(0.98); }

.btn-primary { background: var(--c-text); color: #000; }
.btn-primary:hover { background: #e0e0e2; }

.btn-secondary {
  background: transparent;
  color: var(--c-text);
  border: 1px solid var(--c-border);
}
.btn-secondary:hover { background: rgba(255,255,255,.08); border-color: rgba(255,255,255,.25); }

.btn:disabled { opacity: 0.45; cursor: default; transform: none; }

/* ── Back link ──────────────────────────────────────────────────────────────── */
.back-link {
  background: none;
  border: none;
  color: var(--c-subtext);
  font-family: inherit;
  font-size: 0.875rem;
  cursor: pointer;
  padding: 0.25em 0;
  text-decoration: underline;
  text-underline-offset: 3px;
  transition: color var(--dur-micro) var(--ease-out);
}
.back-link:hover { color: var(--c-text); }

/* ── Messages ───────────────────────────────────────────────────────────────── */
.msg {
  font-size: 0.875rem;
  padding: 0.6em 1em;
  border-radius: 10px;
  text-align: center;
  line-height: 1.4;
}
.msg[hidden] { display: none; }
.msg-error   { background: rgba(255, 69, 58, 0.15); color: var(--c-error); }
.msg-info    { background: rgba(255, 255, 255, 0.06); color: var(--c-subtext); }
.msg-success { background: rgba(50, 215, 75, 0.12); color: var(--c-success); }

/* ── Responsive breakpoints (Apple conventions) ─────────────────────────────── */
@media (max-width: 1068px) {
  h1          { grid-column: 2 / 12; }
  .subtitle   { grid-column: 3 / 11; }
  .login-card { grid-column: 3 / 11; }
}

@media (max-width: 980px) {
  h1          { grid-column: 2 / 12; }
  .subtitle   { grid-column: 2 / 12; }
  .login-card { grid-column: 2 / 12; }
}

/* ≤ 734px: single column, reduce spacing */
@media (max-width: 734px) {
  h1, .subtitle, .login-card { grid-column: 1 / -1; }
  .wordmark { margin-bottom: 3rem; }
  .subtitle { margin-bottom: 2rem; }
}

@media (max-width: 320px) {
  body { padding: 12px; }
}

/* ── Accessibility: honor reduced-motion ────────────────────────────────────── */
@media (prefers-reduced-motion: reduce) {
  .step.entering,
  .step.exiting { animation: none; opacity: 1; transform: none; }
  .btn, .field, .back-link { transition: none; }
}