:root {
  color-scheme: dark;
  --bg: #0c0c0c;
  --card: #161616;
  --line: rgba(255, 255, 255, 0.1);
  --muted: rgba(255, 255, 255, 0.58);
  --faint: rgba(255, 255, 255, 0.38);
}

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

html,
body {
  margin: 0;
  min-height: 100%;
  background: var(--bg);
}

body {
  min-height: 100svh;
  overflow-x: hidden;
  color: #f4f4f4;
  font-family: Inter, "Segoe UI", sans-serif;
  -webkit-font-smoothing: antialiased;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background:
    linear-gradient(90deg, transparent 18%, rgba(255, 255, 255, 0.045) 18%, transparent 18.08%),
    linear-gradient(90deg, transparent 82%, rgba(255, 255, 255, 0.045) 82%, transparent 82.08%);
}

h1,
p {
  margin: 0;
}

button,
input {
  font-family: inherit;
}

::selection {
  background: #f4f4f4;
  color: #111;
}

:focus-visible {
  outline: 2px solid #f4f4f4;
  outline-offset: 3px;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.books {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  overflow: hidden;
}

.book {
  position: absolute;
  width: 200px;
  aspect-ratio: 3 / 4;
  object-fit: cover;
  border-radius: 3px;
  box-shadow: 0 22px 40px rgba(0, 0, 0, 0.5), 0 2px 6px rgba(0, 0, 0, 0.35);
}

.b1 { top: -46px; left: 5%; width: 210px; transform: rotate(-16deg); }
.b2 { top: -54px; right: 6%; width: 220px; transform: rotate(13deg); }
.b3 { top: 30%; left: -40px; width: 210px; transform: rotate(-8deg); }
.b4 { top: 26%; right: -34px; width: 220px; transform: rotate(9deg); }
.b5 { bottom: -56px; left: 7%; width: 200px; transform: rotate(11deg); }
.b6 { bottom: -48px; right: 6%; width: 210px; transform: rotate(-12deg); }

.stage {
  position: relative;
  z-index: 1;
  min-height: 100svh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 4.5rem 1.25rem;
  text-align: center;
}

.brand {
  margin-bottom: 1.1rem;
  font-size: 0.78rem;
  font-weight: 500;
  letter-spacing: 0.22em;
  text-transform: uppercase;
}

h1 {
  max-width: 11ch;
  font-family: "Instrument Serif", Georgia, serif;
  font-size: clamp(3rem, 8vw, 4.4rem);
  font-weight: 400;
  line-height: 0.95;
  letter-spacing: -0.03em;
}

h1 em {
  font-style: italic;
  font-weight: 400;
}

.sub {
  max-width: 36ch;
  margin-top: 1.15rem;
  color: var(--muted);
  font-size: 0.95rem;
  line-height: 1.5;
}

.invite {
  margin-top: 0.75rem;
  color: #f4f4f4;
  font-size: 0.9rem;
}

.card {
  width: min(100%, 360px);
  margin-top: 2rem;
  padding: 0.7rem;
  border-radius: 18px;
  background: var(--card);
  box-shadow: inset 0 0 0 1px var(--line);
}

.card input {
  width: 100%;
  height: 48px;
  border: 0;
  border-radius: 12px;
  background: #101010;
  box-shadow: inset 0 0 0 1px var(--line);
  color: #f4f4f4;
  font-size: 0.95rem;
  padding: 0 14px;
}

.card input::placeholder {
  color: var(--faint);
}

.card input:-webkit-autofill {
  -webkit-text-fill-color: #f4f4f4;
  caret-color: #f4f4f4;
  box-shadow: 0 0 0 1000px #101010 inset;
}

#submit-btn,
.copy {
  width: 100%;
  height: 48px;
  margin-top: 0.55rem;
  border: 0;
  border-radius: 12px;
  background: #f4f4f4;
  color: #111;
  font-size: 0.95rem;
  font-weight: 500;
  cursor: pointer;
}

#submit-btn:hover,
.copy:hover {
  background: #fff;
}

#submit-btn:disabled {
  opacity: 0.6;
  cursor: progress;
}

.copy .label-done { display: none; }
.copy.is-copied .label-idle { display: none; }
.copy.is-copied .label-done { display: inline; }

.form-error {
  margin-top: 0.55rem;
  color: #e7b4ae;
  font-size: 0.85rem;
}

.form-error:empty { display: none; }

.shares {
  display: flex;
  justify-content: center;
  gap: 0.4rem;
  margin-top: 0.7rem;
}

.share {
  display: inline-flex;
  align-items: center;
  height: 34px;
  padding: 0 0.75rem;
  border-radius: 999px;
  color: var(--muted);
  background: transparent;
  box-shadow: inset 0 0 0 1px var(--line);
  text-decoration: none;
  font-size: 0.78rem;
}

.share:hover {
  color: #f4f4f4;
}

@media (max-width: 900px) {
  .b3, .b4 { display: none; }
  .book { width: 128px; }
}

@media (max-width: 520px) {
  h1 { font-size: 2.7rem; }
  .stage { padding: 3rem 1rem; }
  .b5, .b6 { display: none; }
}