/* Shared static shell for machine-mail.html, send-message.html, trust-in-mailbox.html (nginx root). */
:root {
  --bg: #f3f5fa;
  --surface: #ffffff;
  --surface-2: #f8faff;
  --text: #111827;
  --muted: #5b6677;
  --border: #d6deeb;
  --accent: #2b63f1;
  --accent-strong: #1f4ec7;
  --accent-soft: #eaf0ff;
  --ok: #1f8f4c;
  --err: #c1323a;
  --radius: 12px;
  --radius-sm: 10px;
  --shadow-sm: 0 1px 2px rgba(17, 24, 39, 0.08);
  --control-bg: #ffffff;
  --focus-ring: 0 0 0 3px rgba(43, 99, 241, 0.2);
}
[data-theme="dark"] {
  --bg: #0f141d;
  --surface: #161d2a;
  --surface-2: #1b2433;
  --text: #e7ecf5;
  --muted: #a9b4c7;
  --border: #2f3a4d;
  --accent: #88a9ff;
  --accent-strong: #b3c7ff;
  --accent-soft: #1b2a4e;
  --ok: #4dd087;
  --err: #ff7d88;
  --control-bg: #121925;
  --focus-ring: 0 0 0 3px rgba(136, 169, 255, 0.32);
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
}
[data-density="compact"] {
  --layout-pad: 14px;
  --card-pad: 10px;
}
* {
  box-sizing: border-box;
}
body {
  font-family: Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  margin: 0;
  color: var(--text);
  background: var(--bg);
}
.layout {
  display: grid;
  grid-template-columns: 240px 1fr;
  grid-template-rows: 64px 1fr 52px;
  min-height: 100vh;
  grid-template-areas:
    "top top"
    "left main"
    "bottom bottom";
}
.top {
  grid-area: top;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 18px;
}
.left {
  grid-area: left;
  background: var(--surface);
  border-right: 1px solid var(--border);
  padding: 16px 12px;
}
.main {
  grid-area: main;
  padding: var(--layout-pad, 18px);
  min-width: 0;
}
.main.main--max-sm {
  max-width: 760px;
}
.main.main--max-md {
  max-width: 900px;
}
.bottom {
  grid-area: bottom;
  background: var(--surface);
  border-top: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px;
  padding: 10px 18px;
  color: var(--muted);
  font-size: 13px;
}
.brand {
  font-weight: 700;
  letter-spacing: 0.2px;
}
.top-right {
  display: inline-flex;
  align-items: center;
  gap: 10px;
}
.domain {
  color: var(--muted);
  font-size: 13px;
}
.nav {
  display: grid;
  gap: 14px;
}
.nav-group {
  display: grid;
  gap: 6px;
}
.nav-group-label {
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--muted);
  padding: 0 4px;
}
.nav a {
  display: block;
  text-decoration: none;
  color: var(--text);
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--control-bg);
  box-shadow: var(--shadow-sm);
}
.nav a.active {
  border-color: var(--accent);
  color: var(--accent-strong);
  font-weight: 600;
  background: var(--accent-soft);
}
.footer-links a {
  color: var(--accent);
  text-decoration: none;
}
.footer-links a:hover {
  text-decoration: underline;
}
.section-title {
  margin: 0 0 6px;
}
.subtitle {
  color: var(--muted);
  margin: 0 0 14px;
  font-size: 14px;
}
.intro {
  font-size: 14px;
  line-height: 1.55;
  margin: 0 0 18px;
  padding: 14px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface-2);
  box-shadow: var(--shadow-sm);
}
.intro p {
  margin: 0 0 12px;
}
.intro p:last-child {
  margin-bottom: 0;
}
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 14px;
}
.card {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: var(--card-pad, 14px);
  background: var(--surface);
  box-shadow: var(--shadow-sm);
}
h1,
h2 {
  margin: 0 0 10px;
}
form {
  display: grid;
  gap: 8px;
}
label {
  display: grid;
  gap: 6px;
}
input,
button,
select,
textarea {
  padding: 9px;
  font-size: 14px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--control-bg);
  color: var(--text);
}
textarea {
  min-height: 100px;
  resize: vertical;
  font-family: inherit;
}
button {
  cursor: pointer;
  border-color: var(--accent);
  background: var(--accent);
  color: #fff;
  font-weight: 600;
}
button:hover {
  background: var(--accent-strong);
  border-color: var(--accent-strong);
}
button:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible,
a:focus-visible {
  outline: none;
  box-shadow: var(--focus-ring);
}
pre {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 10px;
  overflow-x: auto;
  max-height: 360px;
}
.meta {
  color: var(--muted);
  font-size: 14px;
}
.ok {
  color: var(--ok);
}
.err {
  color: var(--err);
}
.card.anchor-target {
  scroll-margin-top: 72px;
}
.theme-toggle {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--control-bg);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 6px 10px;
  font-size: 13px;
  line-height: 1;
  box-shadow: var(--shadow-sm);
}

/* send-message.html: slightly roomier form */
.main--max-sm form {
  gap: 10px;
  max-width: 640px;
}
.main--max-sm input,
.main--max-sm button,
.main--max-sm textarea {
  padding: 10px;
  font-size: 15px;
}
.main--max-sm textarea {
  min-height: 160px;
}

/* trust-in-mailbox.html */
.main--max-md form {
  gap: 10px;
}
.main--max-md input,
.main--max-md button,
.main--max-md select,
.main--max-md textarea {
  padding: 10px;
  font-size: 15px;
}
.main--max-md .card h2 {
  font-size: 1.1rem;
}
.main--max-md .card {
  margin-bottom: 14px;
}

@media (max-width: 840px) {
  .layout {
    grid-template-columns: 1fr;
    grid-template-rows: auto auto 1fr auto;
    grid-template-areas: "top" "left" "main" "bottom";
  }
  .left {
    border-right: none;
    border-bottom: 1px solid var(--border);
  }
}