:root {
  --paper: #f2ebdd;
  --paper-deep: #e7dcc8;
  --ink: #1c1813;
  --ink-soft: #5d554a;
  --amber: #b9621c;
  --line: rgba(28, 24, 19, .16);
  --ok: #3f6b4a;
  --bad: #a33b2a;
  --serif: "Iowan Old Style", "Songti SC", "Noto Serif SC", Georgia, serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
}
* { box-sizing: border-box; }
body {
  margin: 0; min-height: 100vh; color: var(--ink); background: var(--paper);
  font: 15px/1.7 var(--sans);
  background-image: linear-gradient(90deg, transparent 0, transparent calc(50% - .5px), var(--line) 50%, transparent calc(50% + .5px));
}
.shell { display: grid; grid-template-columns: minmax(240px, 30%) 1fr; min-height: 100vh; max-width: 1180px; margin: 0 auto; }
.rail { padding: clamp(32px, 6vw, 80px) clamp(24px, 4vw, 56px); border-right: 1px solid var(--line); display: flex; flex-direction: column; }
.brand { display: flex; align-items: baseline; gap: 12px; font: 600 clamp(26px, 3vw, 36px)/1 var(--serif); letter-spacing: .04em; }
.brand small { display: block; margin-top: 8px; font: 500 10px/1 var(--sans); letter-spacing: .34em; color: var(--amber); }
.brand-mark { color: var(--amber); font-size: .7em; }
.rail-intro { margin: clamp(40px, 8vh, 88px) 0 28px; max-width: 25ch; font-size: 14px; color: var(--ink-soft); }
.steps { list-style: none; margin: 0; padding: 0; }
.steps li { display: flex; align-items: center; gap: 14px; padding: 12px 0; border-top: 1px solid var(--line); color: var(--ink-soft); font-size: 14px; }
.steps li:last-child { border-bottom: 1px solid var(--line); }
.step-num { display: inline-grid; place-items: center; width: 26px; height: 26px; border: 1px solid var(--line); border-radius: 50%; font: 500 12px/1 var(--sans); }
.steps .current { color: var(--ink); font-weight: 600; }
.steps .current .step-num { background: var(--amber); border-color: var(--amber); color: #fff; }
.steps .done .step-num { background: var(--ink); color: var(--paper); border-color: var(--ink); }
.rail-foot { margin-top: auto; padding-top: 40px; font-size: 12px; line-height: 1.9; color: var(--ink-soft); }
.panel { padding: clamp(36px, 7vw, 92px) clamp(24px, 6vw, 84px); }
h1 { font: 500 clamp(30px, 4vw, 46px)/1.15 var(--serif); letter-spacing: -.01em; margin: 0 0 14px; }
.lead { margin: 0 0 36px; max-width: 58ch; color: var(--ink-soft); }
.muted { color: var(--ink-soft); font-size: 13px; }
code { font: 13px/1.5 ui-monospace, SFMono-Regular, Consolas, monospace; background: var(--paper-deep); padding: 2px 6px; }
.checks { list-style: none; padding: 0; margin: 0 0 36px; border-top: 1px solid var(--line); }
.checks li { display: grid; grid-template-columns: 12px 1fr auto auto; gap: 16px; align-items: center; padding: 11px 2px; border-bottom: 1px solid var(--line); font-size: 14px; }
.dot { width: 7px; height: 7px; border-radius: 50%; background: var(--ok); }
.bad .dot { background: var(--bad); }
.warn .dot { background: #b9ab93; }
.check-detail, .check-state { color: var(--ink-soft); font-size: 12px; }
.bad .check-state { color: var(--bad); }
.form-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 22px 26px; max-width: 620px; }
.form-grid label { display: block; font-size: 12px; letter-spacing: .08em; color: var(--ink-soft); }
.form-grid label.full, .form-grid .full { grid-column: 1 / -1; }
input[type=text], input[type=password], input[type=number], input[type=email], input:not([type]) {
  display: block; width: 100%; margin-top: 8px; padding: 11px 12px; font: 15px/1.4 var(--sans); color: var(--ink);
  background: transparent; border: none; border-bottom: 1px solid var(--ink-soft); border-radius: 0; outline: none;
}
input:focus { border-bottom-color: var(--amber); box-shadow: 0 1px 0 var(--amber); }
.checkbox { display: flex !important; align-items: center; gap: 10px; letter-spacing: 0 !important; font-size: 14px !important; }
.checkbox input { width: auto; margin: 0; accent-color: var(--amber); }
.hint { margin: 0; font-size: 12px; color: var(--ink-soft); }
.summary { margin: 0 0 36px; border-top: 1px solid var(--line); }
.summary div { display: grid; grid-template-columns: 120px 1fr; gap: 20px; padding: 12px 0; border-bottom: 1px solid var(--line); }
.summary dt { color: var(--ink-soft); font-size: 13px; }
.summary dd { margin: 0; font-family: var(--serif); font-size: 17px; word-break: break-all; }
.install-log { padding: 0 0 0 20px; margin: 0 0 36px; color: var(--ink-soft); font-size: 14px; }
.install-log li { padding: 5px 0; }
.actions { display: flex; flex-wrap: wrap; gap: 14px; align-items: center; margin-top: 12px; }
.btn { display: inline-flex; align-items: center; justify-content: center; padding: 12px 24px; border: 1px solid var(--ink);
  background: var(--ink); color: var(--paper); font: 500 14px/1 var(--sans); text-decoration: none; cursor: pointer; letter-spacing: .04em; }
.btn:hover { background: var(--amber); border-color: var(--amber); }
.btn:disabled { opacity: .4; cursor: not-allowed; }
.btn.ghost { background: transparent; color: var(--ink); }
.btn.ghost:hover { color: var(--amber); }
.notice { padding: 12px 16px; margin-bottom: 28px; border-left: 3px solid var(--bad); background: rgba(163, 59, 42, .07); font-size: 14px; }
.security { margin-top: 36px; padding-top: 18px; border-top: 1px solid var(--line); }
@media (max-width: 760px) {
  .shell { grid-template-columns: 1fr; }
  .rail { border-right: 0; border-bottom: 1px solid var(--line); padding-bottom: 28px; }
  .rail-intro, .rail-foot { display: none; }
  .form-grid { grid-template-columns: 1fr; }
}
@media (prefers-reduced-motion: no-preference) {
  .btn { transition: background .2s ease, color .2s ease, border-color .2s ease; }
}