:root {
  --paper: #f4efe5;
  --paper-light: #fffaf2;
  --paper-deep: #e9dfcf;
  --ink: #292824;
  --ink-soft: #6d6860;
  --brick: #954f40;
  --brick-dark: #713c32;
  --canal: #65858d;
  --moss: #66745d;
  --rule: rgba(41, 40, 36, 0.18);
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  --serif: Georgia, "Times New Roman", Times, serif;
  color-scheme: light;
}

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

html,
body {
  min-width: 320px;
  min-height: 100%;
}

body {
  margin: 0;
  overflow-x: hidden;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 1rem;
  line-height: 1.7;
}

body::before {
  position: fixed;
  z-index: 10;
  inset: 0;
  background-image: radial-gradient(rgba(41, 40, 36, 0.12) 0.45px, transparent 0.6px);
  background-size: 5px 5px;
  content: "";
  opacity: 0.18;
  pointer-events: none;
}

[hidden] {
  display: none !important;
}

html.letter-preunlocked #lockGate {
  display: none !important;
}

html.letter-preunlocked #letterContent[hidden] {
  display: grid !important;
}

a,
button,
input {
  font: inherit;
}

a {
  color: inherit;
}

a:focus-visible,
button:focus-visible,
input:focus-visible {
  outline: 2px solid var(--canal);
  outline-offset: 4px;
}

.return-link {
  position: fixed;
  z-index: 20;
  top: max(18px, env(safe-area-inset-top));
  left: max(20px, env(safe-area-inset-left));
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  color: var(--ink-soft);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-decoration: none;
  text-transform: uppercase;
}

.return-link::after {
  position: absolute;
  right: 0;
  bottom: 7px;
  left: 0;
  height: 1px;
  background: currentColor;
  content: "";
  transform: scaleX(0.28);
  transform-origin: left;
  transition: transform 180ms ease;
}

.return-link:hover::after {
  transform: scaleX(1);
}

.lock-gate,
.future-letter {
  position: relative;
  isolation: isolate;
  min-height: 100vh;
  min-height: 100svh;
  padding: max(88px, calc(env(safe-area-inset-top) + 72px)) max(24px, env(safe-area-inset-right)) max(58px, calc(env(safe-area-inset-bottom) + 42px)) max(24px, env(safe-area-inset-left));
}

.lock-gate {
  display: grid;
  overflow: hidden;
  place-items: center;
}

.lock-gate::before,
.lock-gate::after {
  position: absolute;
  z-index: -1;
  content: "";
  pointer-events: none;
}

.lock-gate::before {
  top: 8%;
  right: -80px;
  width: 230px;
  height: 320px;
  border: 1px solid rgba(101, 133, 141, 0.2);
  border-radius: 50%;
  transform: rotate(16deg);
}

.lock-gate::after {
  bottom: 8%;
  left: 6%;
  width: 54px;
  height: 54px;
  border: 1px solid rgba(149, 79, 64, 0.24);
  border-radius: 50%;
  box-shadow: inset 0 0 0 7px var(--paper), inset 0 0 0 8px rgba(149, 79, 64, 0.16);
}

.lock-layout {
  width: min(100%, 460px);
  text-align: center;
}

.letter-meta,
.letter-date {
  margin: 0;
  font-size: 0.68rem;
  font-weight: 750;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.letter-meta {
  color: var(--brick);
}

.letter-date {
  margin-top: 2px;
  color: var(--ink-soft);
}

.lock-envelope {
  position: relative;
  width: 146px;
  height: 96px;
  margin: 38px auto 46px;
  filter: drop-shadow(0 14px 18px rgba(57, 45, 32, 0.14));
  perspective: 700px;
}

.lock-envelope-paper,
.lock-envelope-back,
.lock-envelope-front,
.lock-envelope-flap,
.lock-envelope-seal {
  position: absolute;
}

.lock-envelope-back {
  inset: 0;
  border: 1px solid rgba(41, 40, 36, 0.18);
  background: #eadfcd;
}

.lock-envelope-paper {
  z-index: 1;
  right: 10px;
  bottom: 7px;
  left: 10px;
  height: 80px;
  border: 1px solid rgba(41, 40, 36, 0.11);
  background: var(--paper-light);
  transition: transform 520ms 230ms cubic-bezier(0.2, 0.72, 0.2, 1);
}

.lock-envelope-paper::before,
.lock-envelope-paper::after {
  position: absolute;
  left: 18px;
  height: 1px;
  background: rgba(41, 40, 36, 0.14);
  content: "";
}

.lock-envelope-paper::before {
  top: 20px;
  width: 62px;
}

.lock-envelope-paper::after {
  top: 31px;
  width: 88px;
}

.lock-envelope-front {
  z-index: 3;
  inset: 0;
  overflow: hidden;
}

.lock-envelope-front::before,
.lock-envelope-front::after {
  position: absolute;
  bottom: -50px;
  width: 108px;
  height: 112px;
  border: 1px solid rgba(41, 40, 36, 0.13);
  background: #efe4d2;
  content: "";
}

.lock-envelope-front::before {
  left: -30px;
  transform: rotate(42deg);
}

.lock-envelope-front::after {
  right: -30px;
  transform: rotate(-42deg);
}

.lock-envelope-flap {
  z-index: 4;
  top: 0;
  left: 0;
  width: 146px;
  height: 76px;
  border: 1px solid rgba(41, 40, 36, 0.16);
  background: #e5d8c4;
  clip-path: polygon(0 0, 100% 0, 50% 100%);
  transform-origin: top;
  transition: transform 520ms cubic-bezier(0.45, 0, 0.2, 1), z-index 0s 240ms;
}

.lock-envelope-seal {
  z-index: 5;
  top: 48px;
  left: 50%;
  display: grid;
  width: 31px;
  height: 31px;
  place-items: center;
  border-radius: 50%;
  background: var(--brick);
  box-shadow: inset 0 0 0 3px rgba(255, 250, 242, 0.16);
  color: var(--paper-light);
  font-family: var(--serif);
  font-size: 0.76rem;
  transform: translateX(-50%);
  transition: opacity 180ms ease, transform 180ms ease;
}

.lock-gate.is-unlocking .lock-envelope-flap {
  z-index: 0;
  transform: rotateX(176deg);
}

.lock-gate.is-unlocking .lock-envelope-paper {
  transform: translateY(-52px);
}

.lock-gate.is-unlocking .lock-envelope-seal {
  opacity: 0;
  transform: translateX(-50%) scale(0.7);
}

.lock-copy h1,
.future-letter h1 {
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(2.25rem, 12vw, 3.7rem);
  font-weight: 400;
  letter-spacing: 0;
  line-height: 1.02;
}

.lock-copy > p {
  max-width: 390px;
  margin: 22px auto 0;
  color: var(--ink-soft);
  line-height: 1.65;
}

.password-form {
  width: min(100%, 370px);
  margin: 38px auto 0;
  text-align: left;
}

.password-label {
  display: block;
  margin-bottom: 8px;
  color: var(--ink-soft);
  font-size: 0.7rem;
  font-weight: 750;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.password-row {
  display: grid;
  grid-template-columns: 1fr;
  gap: 10px;
}

.password-row input,
.password-row button {
  width: 100%;
  min-height: 54px;
  border-radius: 0;
}

.password-row input {
  border: 0;
  border-bottom: 1px solid var(--ink);
  background: rgba(255, 250, 242, 0.48);
  color: var(--ink);
  font-size: 16px;
  padding: 13px 12px;
}

.password-row input::placeholder {
  color: #8a857d;
}

.password-row button {
  border: 1px solid var(--ink);
  background: var(--ink);
  color: var(--paper-light);
  cursor: pointer;
  font-size: 0.78rem;
  font-weight: 750;
  letter-spacing: 0.05em;
  padding: 12px 18px;
  transition: background 180ms ease, border-color 180ms ease, transform 180ms ease;
}

.password-row button:hover {
  border-color: var(--brick-dark);
  background: var(--brick-dark);
  transform: translateY(-1px);
}

.password-row button:disabled {
  cursor: default;
  opacity: 0.62;
}

.password-error {
  min-height: 26px;
  margin: 8px 0 0;
  color: var(--brick-dark);
  font-size: 0.8rem;
}

.password-hint {
  margin: 14px 0 0;
  color: var(--ink-soft);
  font-family: var(--serif);
  font-size: 0.86rem;
  font-style: italic;
  text-align: center;
}

.password-form.has-error {
  animation: quiet-shake 320ms ease;
}

.future-letter {
  display: grid;
  place-items: center;
  text-align: center;
}

.future-letter::before {
  position: absolute;
  z-index: -1;
  top: 14%;
  left: 50%;
  width: min(72vw, 420px);
  height: min(72vw, 420px);
  border: 1px solid rgba(101, 133, 141, 0.22);
  border-radius: 50%;
  content: "";
  transform: translateX(-50%);
}

.future-letter-inner {
  width: min(100%, 650px);
}

.future-letter .letter-meta {
  margin-bottom: 22px;
}

.future-letter h1 {
  font-size: clamp(3.6rem, 20vw, 7.6rem);
}

.future-letter-found {
  margin: 34px 0 0;
  font-family: var(--serif);
  font-size: clamp(1.15rem, 5vw, 1.55rem);
}

.future-letter-writing {
  margin: 8px 0 0;
  color: var(--ink-soft);
}

.future-return {
  display: inline-block;
  min-height: 44px;
  margin-top: 52px;
  color: var(--ink-soft);
  font-size: 0.72rem;
  font-weight: 750;
  letter-spacing: 0.08em;
  line-height: 44px;
  text-decoration-color: rgba(41, 40, 36, 0.4);
  text-underline-offset: 5px;
  text-transform: uppercase;
}

.future-letter.is-arriving .future-letter-inner {
  animation: letter-arrives 620ms cubic-bezier(0.2, 0.72, 0.2, 1) both;
}

@keyframes quiet-shake {
  25% { transform: translateX(-3px); }
  50% { transform: translateX(3px); }
  75% { transform: translateX(-2px); }
}

@keyframes letter-arrives {
  from { opacity: 0; transform: translateY(14px); }
  to { opacity: 1; transform: translateY(0); }
}

@media (min-width: 600px) {
  .password-row {
    grid-template-columns: minmax(0, 1fr) auto;
  }

  .password-row button {
    width: auto;
    min-width: 152px;
  }
}

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