:root {
  --paper: #f6f2ea; --paper-2: #ede7db; --card: #fffdf8;
  --ink: #1c1a17; --ink-2: #5a544b; --ink-3: #8a8378; --line: #d9d1c3;
  --accent: #d2451e; --accent-ink: #fff; --accent-soft: #f7dccf; --mark: #1f6f68; --danger: #b42318;
  --radius: 14px;
  --font: -apple-system, BlinkMacSystemFont, 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
  --mono: ui-monospace, 'SF Mono', Menlo, Consolas, monospace;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root {
    --paper: #15140f; --paper-2: #1e1c17; --card: #1c1b16;
    --ink: #efe9dd; --ink-2: #b9b1a3; --ink-3: #847d71; --line: #34312a;
    --accent: #f06a3f; --accent-ink: #1a0d07; --accent-soft: #3a2017; --mark: #5bbdb2; --danger: #f97066;
    color-scheme: dark;
  }
}
*, *::before, *::after { box-sizing: border-box; }
body { margin: 0; background: var(--paper); color: var(--ink); font-family: var(--font); line-height: 1.7; -webkit-font-smoothing: antialiased; }
a { color: inherit; }
.wrap { max-width: 1080px; margin: 0 auto; padding: 0 20px; }
.narrow { max-width: 520px; }
.mono { font-family: var(--mono); font-size: .78rem; letter-spacing: .06em; text-transform: uppercase; color: var(--ink-3); }
.muted { color: var(--ink-2); }
.small { font-size: .88rem; }

.site-header { position: sticky; top: 0; z-index: 10; background: color-mix(in srgb, var(--paper) 90%, transparent); backdrop-filter: blur(10px); border-bottom: 1px solid var(--line); }
.site-header .wrap { display: flex; align-items: center; justify-content: space-between; height: 58px; gap: 12px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; text-decoration: none; white-space: nowrap; }
.brand-dot { width: 22px; height: 22px; border-radius: 6px; background: var(--ink); position: relative; }
.brand-dot::after { content: ''; position: absolute; inset: 6px 5px 6px 8px; background: var(--accent); clip-path: polygon(0 0, 100% 50%, 0 100%); }
.nav { display: flex; align-items: center; gap: 4px; }
.nav a, .nav button.link { text-decoration: none; padding: 6px 10px; border-radius: 8px; color: var(--ink-2); font: inherit; font-size: .93rem; background: none; border: 0; cursor: pointer; }
.nav a:hover, .nav button.link:hover { background: var(--paper-2); color: var(--ink); }
.nav form { margin: 0; }

.btn { display: inline-flex; align-items: center; justify-content: center; gap: 8px; padding: 10px 20px; border-radius: 999px; background: var(--accent); color: var(--accent-ink); font: inherit; font-weight: 600; text-decoration: none; border: 0; cursor: pointer; }
.btn:disabled { opacity: .5; cursor: not-allowed; }
.btn.ghost { background: transparent; color: var(--ink); box-shadow: inset 0 0 0 1px var(--line); }
.btn.block { width: 100%; padding: 13px; font-size: 1.02rem; }
.btn.sm { padding: 6px 14px; font-size: .88rem; }

main { padding: 40px 0 72px; min-height: 60vh; }
h1 { font-size: clamp(1.6rem, 4vw, 2.3rem); line-height: 1.3; margin: 6px 0 12px; }
h2 { font-size: 1.25rem; margin: 32px 0 14px; }

.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 20px; }
.grid { display: grid; gap: 16px; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); }
a.card { display: block; text-decoration: none; transition: border-color .15s, transform .15s; }
a.card:hover { border-color: var(--ink-3); transform: translateY(-2px); }

.price { font-size: 2rem; font-weight: 800; line-height: 1.2; }
.price small { font-size: 1rem; margin-right: 2px; }
.price del { font-size: .95rem; font-weight: 400; color: var(--ink-3); margin-left: 8px; }
.tag { display: inline-block; font-size: .78rem; padding: 2px 8px; border-radius: 6px; background: var(--paper-2); color: var(--ink-2); }
.tag.accent { background: var(--accent-soft); color: var(--accent); }
.tag.ok { background: color-mix(in srgb, var(--mark) 15%, transparent); color: var(--mark); }

.flash { padding: 12px 16px; border-radius: 10px; margin-bottom: 20px; }
.flash.error { background: color-mix(in srgb, var(--danger) 12%, transparent); color: var(--danger); }
.flash.success { background: color-mix(in srgb, var(--mark) 14%, transparent); color: var(--mark); }

label { display: block; font-weight: 600; margin: 16px 0 6px; font-size: .93rem; }
input[type=text], input[type=tel], textarea { width: 100%; font: inherit; padding: 11px 14px; border-radius: 10px; border: 1px solid var(--line); background: var(--card); color: var(--ink); }
input:focus, textarea:focus { outline: 2px solid var(--accent); outline-offset: 1px; }
.field-row { display: flex; gap: 10px; }
.field-row input { flex: 1; min-width: 0; }
.error-text { color: var(--danger); font-size: .85rem; margin-top: 4px; }

.syllabus .chapter { margin-bottom: 12px; }
.syllabus .chapter h3 { font-size: 1rem; margin: 0 0 8px; }
.lesson-row { display: flex; justify-content: space-between; align-items: center; gap: 12px; padding: 9px 0; border-top: 1px dashed var(--line); text-decoration: none; }
.lesson-row:first-of-type { border-top: 0; }
.lesson-row .meta { display: flex; gap: 8px; align-items: center; color: var(--ink-3); font-size: .85rem; white-space: nowrap; }
a.lesson-row:hover .title { color: var(--accent); }
.lesson-row.current .title { color: var(--accent); font-weight: 600; }

.progress { height: 6px; border-radius: 99px; background: var(--paper-2); overflow: hidden; }
.progress > span { display: block; height: 100%; background: var(--mark); }

table.list { width: 100%; border-collapse: collapse; font-size: .92rem; }
table.list th, table.list td { text-align: left; padding: 12px 10px; border-bottom: 1px solid var(--line); vertical-align: top; }
table.list th { color: var(--ink-3); font-weight: 500; }
.table-wrap { overflow-x: auto; }

.site-footer { border-top: 1px solid var(--line); padding: 28px 0 40px; color: var(--ink-3); font-size: .85rem; }

@media (max-width: 720px) {
  .wrap { padding: 0 16px; }
  .nav .hide-sm { display: none; }
  main { padding: 28px 0 56px; }
}