:root {
  --bg: #f7f5f0;
  --ink: #1d1c1a;
  --muted: #6d6a63;
  --cipher: #9a958a;
  --cipher-bg: #edeae2;
  --rule: #dcd8ce;
  --accent: #2f5d50;
  --warn: #9b3d2a;
  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --sans: system-ui, -apple-system, "Segoe UI", sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #161614;
    --ink: #e8e5de;
    --muted: #9a968d;
    --cipher: #6f6b62;
    --cipher-bg: #1f1e1b;
    --rule: #2e2d29;
    --accent: #7fb8a4;
    --warn: #e08a73;
  }
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 1.125rem/1.65 var(--serif);
}

main {
  max-width: 40rem;
  margin: 0 auto;
  padding: 3.5rem 1rem 3rem;
}

/* Status line */
.status {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin: 0 0 1.5rem;
  font: 600 0.75rem/1 var(--sans);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
}
.status-dot {
  width: 0.5rem;
  height: 0.5rem;
  border-radius: 50%;
  background: var(--cipher);
}
.unlocked .status-dot { background: var(--accent); }

/* Title and body */
h1 {
  margin: 0 0 2rem;
  font-size: clamp(1.9rem, 6vw, 2.6rem);
  line-height: 1.15;
  font-weight: 600;
  overflow-wrap: anywhere;
}

article { overflow-wrap: break-word; }
article h2 { font-size: 1.35rem; margin: 2.2rem 0 0.6rem; line-height: 1.3; }
article h3 { font-size: 1.15rem; margin: 1.8rem 0 0.5rem; }
article p, article ul, article ol, article blockquote, article pre { margin: 0 0 1.1rem; }
article ul, article ol { padding-left: 1.4rem; }
article blockquote {
  margin-left: 0;
  padding-left: 1rem;
  border-left: 3px solid var(--rule);
  color: var(--muted);
  font-style: italic;
}
article a { color: var(--accent); }
article img { max-width: 100%; height: auto; }
article pre { overflow-x: auto; padding: 0.8rem; background: var(--cipher-bg); border-radius: 6px; }
article code { font: 0.9em var(--mono); }
article hr { border: 0; border-top: 1px solid var(--rule); margin: 2rem 0; }

/* Locked (ciphertext) rendering */
.cipher {
  display: block;
  font-family: var(--mono);
  color: var(--cipher);
  word-break: break-all;
  overflow-wrap: anywhere;
  user-select: all;
}
h1 .cipher {
  font-size: 0.55em;
  font-weight: 400;
  line-height: 1.5;
  letter-spacing: 0.02em;
}
article .cipher {
  margin: 0;
  padding: 1.1rem 1.2rem;
  font-size: 0.8rem;
  line-height: 1.7;
  background: var(--cipher-bg);
  border-radius: 8px;
  max-height: 26rem;
  overflow: hidden;
  -webkit-mask-image: linear-gradient(to bottom, #000 75%, transparent);
          mask-image: linear-gradient(to bottom, #000 75%, transparent);
}
.placeholder { font-style: normal; }

/* Unlock form */
.unlock {
  margin-top: 2.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--rule);
  font-family: var(--sans);
}
.unlocked .unlock { display: none; }

.unlock label {
  display: block;
  margin-bottom: 0.5rem;
  font-size: 0.9rem;
  font-weight: 600;
}
.key-row { display: flex; gap: 0.5rem; }
.key-row input {
  flex: 1;
  min-width: 0;
  padding: 0.6rem 0.75rem;
  font: 16px/1.2 var(--mono); /* 16px stops iOS zooming on focus */
  color: var(--ink);
  background: var(--bg);
  border: 1px solid var(--rule);
  border-radius: 6px;
}
.key-row input:focus { outline: 2px solid var(--accent); outline-offset: 1px; }
.key-row button {
  padding: 0.6rem 1.1rem;
  font: 600 0.95rem var(--sans);
  color: var(--bg);
  background: var(--ink);
  border: 0;
  border-radius: 6px;
  cursor: pointer;
}
.key-message {
  min-height: 1.4em;
  margin: 0.6rem 0 0;
  font-size: 0.875rem;
  color: var(--warn);
}

@media (prefers-reduced-motion: no-preference) {
  .unlocked #body { animation: fade-in 0.4s ease-out; }
}
@keyframes fade-in { from { opacity: 0.4; } to { opacity: 1; } }