/* Tokens + page shell. Palette carried over from the original lecture_1 cards. */
:root {
  --bg: #E6EBEC;
  --surface: #FBFCFC;
  --surface-2: #F1F4F5;
  --ink: #15232A;
  --muted: #5A6B72;
  --line: #C9D3D6;
  --accent: #B06D12;
  --accent-soft: #F3E3C8;
  --good: #2C7A57;
  --good-soft: #DDEFE5;
  --bad: #B2402C;
  --bad-soft: #F5DFDA;
  --on-accent: #FFFFFF;
  --shadow: 0 1px 2px rgba(21,35,42,.06), 0 12px 32px -12px rgba(21,35,42,.22);
  --f-display: "Unbounded", "Golos Text", system-ui, sans-serif;
  --f-body: "Golos Text", system-ui, -apple-system, "Segoe UI", sans-serif;
  --f-mono: "JetBrains Mono", ui-monospace, "SFMono-Regular", Menlo, monospace;
  --maxw: 760px;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0E161A; --surface: #16232A; --surface-2: #1C2B32; --ink: #E3EBED; --muted: #8FA1A8;
    --line: #2B3C43; --accent: #E3A350; --accent-soft: #3A2C17; --good: #62BC90; --good-soft: #17352A;
    --bad: #E57862; --bad-soft: #3D1F19; --on-accent: #1B1206; --shadow: 0 1px 2px rgba(0,0,0,.3), 0 16px 40px -16px rgba(0,0,0,.6);
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #0E161A; --surface: #16232A; --surface-2: #1C2B32; --ink: #E3EBED; --muted: #8FA1A8;
  --line: #2B3C43; --accent: #E3A350; --accent-soft: #3A2C17; --good: #62BC90; --good-soft: #17352A;
  --bad: #E57862; --bad-soft: #3D1F19; --on-accent: #1B1206; --shadow: 0 1px 2px rgba(0,0,0,.3), 0 16px 40px -16px rgba(0,0,0,.6);
  color-scheme: dark;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg); color: var(--ink);
  font-family: var(--f-body); font-size: 16px; line-height: 1.5;
  /* page = column: topbar / main (grows) / sticky actions */
  min-height: 100vh; min-height: 100dvh;
  display: flex; flex-direction: column;
  padding-top: env(safe-area-inset-top, 0px);
}
a { color: inherit; }
button, input { font: inherit; color: inherit; }
button:focus-visible, a:focus-visible, input:focus-visible, label:focus-within { outline: 3px solid var(--accent); outline-offset: 2px; }
kbd { font-family: var(--f-mono); font-size: 12px; border: 1px solid var(--line); border-bottom-width: 2px; border-radius: 4px; padding: 0 5px; background: var(--surface-2); }

.wrap { width: 100%; max-width: var(--maxw); margin: 0 auto; padding-inline: 16px; }
main.wrap { flex: 1 0 auto; padding-block: 12px 28px; display: grid; gap: 20px; align-content: start; }

/* top bar */
.topbar { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 14px 16px 0; display: flex; align-items: center; gap: 8px; }
.brand { font-family: var(--f-display); font-weight: 700; font-size: 17px; text-decoration: none; letter-spacing: .02em; margin-right: auto; display: inline-flex; align-items: center; gap: 8px; }
.brand i { width: 10px; height: 18px; border-radius: 2px; background: linear-gradient(var(--accent) 0 33%, var(--good) 33% 66%, var(--muted) 66%); display: inline-block; }
.nav { display: flex; gap: 4px; flex-wrap: wrap; justify-content: flex-end; }
.nav a { text-decoration: none; font-size: 14px; font-weight: 500; padding: 6px 10px; border-radius: 999px; color: var(--muted); }
.nav a:hover { color: var(--ink); background: var(--surface-2); }
.nav a[aria-current="page"] { color: var(--ink); background: var(--surface); box-shadow: inset 0 0 0 1px var(--line); }
.nav .nav-account { color: var(--ink); border: 1px solid var(--line); }

/* headings */
.eyebrow { font-size: 12px; letter-spacing: .08em; text-transform: uppercase; color: var(--muted); font-weight: 500; }
h1 { font-family: var(--f-display); font-weight: 700; font-size: clamp(20px, 4.2vw, 28px); line-height: 1.15; margin: 4px 0 0; text-wrap: balance; }
h2 { font-family: var(--f-display); font-weight: 500; font-size: 17px; margin: 0; }
.page-head { display: flex; flex-wrap: wrap; align-items: end; justify-content: space-between; gap: 12px; }
.head-actions { display: flex; gap: 8px; flex-wrap: wrap; }
.muted { color: var(--muted); }
.small { font-size: 14px; }

/* buttons */
.ghost { font: 500 14px var(--f-body); color: var(--ink); background: transparent; border: 1px solid var(--line); border-radius: 999px; padding: 8px 14px; cursor: pointer; text-decoration: none; display: inline-flex; align-items: center; gap: 6px; }
.ghost:hover { border-color: var(--muted); }
.ghost[aria-pressed="true"] { background: var(--accent-soft); border-color: var(--accent); color: var(--accent); }
.btn { font: 600 18px var(--f-body); padding: 15px 16px; border-radius: 14px; border: 1.5px solid var(--line); background: var(--surface); color: var(--ink); cursor: pointer; display: flex; align-items: center; justify-content: center; gap: 10px; transition: transform .08s, border-color .15s, background .15s; text-decoration: none; text-align: center; }
.btn:hover { border-color: var(--muted); }
.btn:active { transform: translateY(1px); }
.btn:disabled { opacity: .5; cursor: default; transform: none; }
.btn kbd { font-weight: 500; color: var(--muted); }
.btn.dark { background: var(--ink); color: var(--surface); border-color: var(--ink); }
.btn.dark:hover { opacity: .9; }
.btn.dark kbd { background: transparent; color: inherit; opacity: .7; border-color: currentColor; }
.btn.primary { background: var(--accent); border-color: var(--accent); color: var(--on-accent); }
.btn.primary:hover { opacity: .92; }
.btn.small { font-size: 16px; padding: 12px 18px; }
.link-btn { background: none; border: 0; padding: 0; color: var(--accent); font-weight: 500; cursor: pointer; text-decoration: underline; text-underline-offset: 3px; }

/* panels */
.panel { background: var(--surface); border: 1px solid var(--line); border-radius: 18px; box-shadow: var(--shadow); padding: clamp(18px, 4.5vw, 32px); display: grid; gap: 18px; min-width: 0; }

/* banner (guest notice etc.) */
.banner { display: flex; align-items: center; gap: 12px; padding: 12px 14px; border-radius: 14px; background: var(--accent-soft); color: var(--ink); border: 1px solid color-mix(in srgb, var(--accent) 35%, transparent); }
.banner p { margin: 0; flex: 1; font-size: 15px; }
.banner .x { background: none; border: 0; font-size: 20px; line-height: 1; cursor: pointer; color: var(--muted); padding: 4px 6px; }

/* forms */
.field { display: grid; gap: 6px; }
.field label { font-size: 14px; font-weight: 500; }
.input { width: 100%; padding: 14px 14px; border-radius: 12px; border: 1.5px solid var(--line); background: var(--surface-2); font-size: 17px; }
.input:focus { outline: none; border-color: var(--accent); background: var(--surface); }
.form-error { color: var(--bad); font-size: 14px; margin: 0; min-height: 1.5em; }
.hint { font-size: 13px; color: var(--muted); }

/* toast */
.toast { position: fixed; left: 50%; bottom: calc(24px + env(safe-area-inset-bottom, 0px)); transform: translateX(-50%); background: var(--ink); color: var(--surface); padding: 10px 16px; border-radius: 12px; font-size: 14px; box-shadow: var(--shadow); z-index: 50; max-width: calc(100% - 32px); }

/* dialog */
dialog { border: 1px solid var(--line); border-radius: 18px; background: var(--surface); color: var(--ink); padding: 24px; max-width: min(420px, calc(100% - 32px)); box-shadow: var(--shadow); }
dialog::backdrop { background: rgba(10, 18, 22, .45); }
dialog h2 { margin-bottom: 8px; }
dialog .row { display: flex; gap: 10px; margin-top: 18px; flex-wrap: wrap; }
dialog .row .btn { flex: 1 1 140px; font-size: 16px; padding: 12px; }

.footer { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 8px 16px calc(20px + env(safe-area-inset-bottom, 0px)); font-size: 13px; color: var(--muted); display: flex; gap: 12px; flex-wrap: wrap; justify-content: space-between; }

/* progress ring */
.ring { --p: 0; --size: 56px; width: var(--size); height: var(--size); flex: none; position: relative; display: grid; place-items: center; }
.ring svg { position: absolute; inset: 0; transform: rotate(-90deg); }
.ring .track { stroke: var(--line); }
.ring .bar { stroke: var(--good); stroke-linecap: round; transition: stroke-dashoffset .6s cubic-bezier(.3,.7,.2,1); }
.ring span { font-family: var(--f-mono); font-size: 12px; font-variant-numeric: tabular-nums; }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { transition: none !important; animation: none !important; }
}