:root {
  color-scheme: light dark;
  --bg: #f3f6f9; --panel: #fff; --text: #17212b; --muted: #65717d;
  --line: #cad4de; --soft: #edf3f8; --accent: #1769aa; --accent-text: #fff;
  --danger: #a53030; --danger-bg: #fff0f0; --success: #286847; --success-bg: #eaf7f0;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111417; --panel: #191e23; --text: #eef3f7; --muted: #b4bec8;
    --line: #3b4650; --soft: #222a31; --accent: #73baf0; --accent-text: #09131b;
    --danger: #ffabab; --danger-bg: #3c2225; --success: #a9dfc2; --success-bg: #21372c;
  }
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--text); font-family: "Yu Gothic UI", "Meiryo", sans-serif; line-height: 1.6; }
a { color: var(--accent); }
button, input, textarea { font: inherit; }
.site-header { min-height: 58px; padding: 10px max(16px, calc((100% - 980px) / 2)); display: flex; align-items: center; justify-content: space-between; gap: 20px; border-bottom: 1px solid var(--line); background: var(--panel); }
.brand { color: var(--text); font-size: 20px; font-weight: 800; text-decoration: none; }
nav { display: flex; align-items: center; gap: 14px; color: var(--muted); font-size: 14px; }
nav form { margin: 0; }
.link-button { padding: 0; border: 0; background: none; color: var(--accent); cursor: pointer; }
main { width: min(980px, 100%); margin: 0 auto; padding: 24px 18px 60px; }
h1 { margin: 0; font-size: clamp(25px, 5vw, 36px); line-height: 1.3; }
h2 { margin: 22px 0 10px; font-size: 20px; }
p { margin: 6px 0; }
.page-head { display: flex; justify-content: space-between; align-items: end; gap: 16px; margin-bottom: 18px; }
.page-head p, .help, small, .form-foot span { color: var(--muted); }
.back { display: inline-block; margin-bottom: 8px; font-weight: 700; text-decoration: none; }
.secondary { display: inline-block; padding: 7px 12px; border: 1px solid var(--line); border-radius: 9px; text-decoration: none; background: var(--panel); white-space: nowrap; }
.login-card, .editor-card, .history-item, .record-card { border: 1px solid var(--line); border-radius: 14px; background: var(--panel); box-shadow: 0 8px 28px rgba(16, 35, 50, .06); }
.login-card { width: min(430px, 100%); margin: 7vh auto 0; padding: 24px; }
.login-card form, .editor-card form { display: grid; gap: 15px; margin-top: 18px; }
label { display: grid; gap: 5px; font-weight: 700; }
input, textarea { width: 100%; border: 1px solid var(--line); border-radius: 9px; padding: 11px 12px; background: var(--bg); color: var(--text); }
textarea { resize: vertical; min-height: 220px; }
input:focus, textarea:focus { outline: 3px solid color-mix(in srgb, var(--accent) 25%, transparent); border-color: var(--accent); }
button { border: 0; border-radius: 9px; padding: 10px 18px; background: var(--accent); color: var(--accent-text); font-weight: 800; cursor: pointer; }
.editor-card { padding: 18px; }
.form-foot { display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.flash { margin-bottom: 16px; padding: 11px 13px; border: 1px solid; border-radius: 9px; }
.flash.error { color: var(--danger); background: var(--danger-bg); }
.flash.success { color: var(--success); background: var(--success-bg); }
.record-card { display: block; padding: 16px; color: var(--text); text-decoration: none; }
.record-card:hover, .record-card:focus-visible { border-color: var(--accent); }
.record-card > div { display: flex; justify-content: space-between; gap: 12px; }
.record-card span, .record-card small { color: var(--muted); }
.record-card p { margin: 12px 0; padding: 10px; border-radius: 8px; background: var(--soft); white-space: pre-wrap; }
.history-list { display: grid; gap: 12px; }
.history-item { padding: 15px; }
.history-item > div { display: flex; justify-content: space-between; gap: 10px; }
.history-item span { color: var(--muted); font-size: 13px; }
.history-item p { white-space: pre-wrap; }
.empty { padding: 20px; border: 1px dashed var(--line); border-radius: 10px; color: var(--muted); }
@media (max-width: 620px) {
  .site-header { align-items: flex-start; }
  nav { gap: 8px; flex-wrap: wrap; justify-content: flex-end; }
  nav > span { display: none; }
  main { padding: 17px 12px 45px; }
  .page-head, .form-foot, .record-card > div, .history-item > div { align-items: stretch; flex-direction: column; }
  .form-foot button { width: 100%; }
  .secondary { align-self: flex-start; }
}