/* ============================================================
   Learning hub — shared stylesheet
   Clean light theme, print-friendly. Neutral (cross-topic) accent.
   Used by the root index and per-topic landing pages.
   ============================================================ */

:root {
  --bg:        #fbfaf7;
  --surface:   #ffffff;
  --ink:       #1c1b19;
  --ink-soft:  #55514b;
  --line:      #e7e3db;
  --line-strong:#cfc9bd;

  --accent:    #4f46e5;   /* indigo — neutral across topics */
  --accent-ink:#3730a3;
  --accent-2:  #6366f1;

  --maxw: 54rem;
  --radius: 12px;
  --shadow: 0 1px 2px rgba(28,27,25,.05), 0 8px 24px rgba(28,27,25,.06);
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background:
    radial-gradient(1200px 400px at 50% -200px, #eef0fb 0%, transparent 70%),
    var(--bg);
  color: var(--ink);
  font: 17px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  padding: 3.5rem 1.25rem 6rem;
}

.wrap { max-width: var(--maxw); margin: 0 auto; }

.kicker {
  font-size: .74rem; letter-spacing: .12em; text-transform: uppercase;
  color: var(--accent-ink); font-weight: 700; margin: 0 0 .6rem;
}

h1 { font-size: 2.3rem; line-height: 1.12; margin: 0 0 .5rem; letter-spacing: -.02em; }
h2 {
  font-size: 1.15rem; margin: 2.6rem 0 .9rem; letter-spacing: .01em;
  color: var(--ink-soft); text-transform: uppercase; font-size: .82rem; letter-spacing: .1em; font-weight: 700;
}
.lede { font-size: 1.16rem; color: var(--ink-soft); margin: .3rem 0 1.4rem; max-width: 42rem; }

p { margin: .7rem 0; }
a { color: var(--accent-ink); text-underline-offset: 2px; }

/* ---- Topic / item cards ---- */
.cards { display: grid; gap: 1rem; margin: 1.2rem 0; }
@media (min-width: 42rem){ .cards { grid-template-columns: 1fr 1fr; } }

a.card {
  display: flex; flex-direction: column; text-decoration: none; color: inherit;
  border: 1px solid var(--line-strong); border-radius: var(--radius);
  background: var(--surface); padding: 1.15rem 1.25rem; box-shadow: var(--shadow);
  transition: border-color .15s, transform .15s, box-shadow .15s;
}
a.card:hover { border-color: var(--accent); transform: translateY(-3px); box-shadow: 0 12px 30px rgba(79,70,229,.14); }

a.card .top { display: flex; align-items: center; gap: .7rem; margin-bottom: .55rem; }
a.card .ico {
  width: 2.5rem; height: 2.5rem; border-radius: 10px; flex: none;
  display: grid; place-items: center; font-size: 1.35rem;
  background: #eef0fb; border: 1px solid #dcdffb;
}
a.card h3 { margin: 0; font-size: 1.12rem; letter-spacing: -.01em; }
a.card .tag {
  font-size: .7rem; letter-spacing: .06em; text-transform: uppercase; font-weight: 700;
  color: var(--accent-ink); background: #eef0fb; border: 1px solid #dcdffb;
  padding: .1rem .5rem; border-radius: 999px; margin-left: auto; align-self: flex-start;
}
a.card p { margin: 0; font-size: .93rem; color: var(--ink-soft); flex: 1; }
a.card .foot { margin-top: .8rem; font-size: .8rem; color: var(--ink-soft); font-weight: 600; }
a.card .foot .go { color: var(--accent-ink); }
a.card.wip .tag { color: #b4531a; background: #fdf1e7; border-color: #f6dcc4; }

/* ---- Sub-item list (per-topic landing) ---- */
ul.items { list-style: none; padding: 0; margin: 1.1rem 0; display: grid; gap: .55rem; }
ul.items a {
  display: flex; align-items: baseline; gap: .6rem; text-decoration: none; color: inherit;
  border: 1px solid var(--line); border-radius: 10px; background: var(--surface);
  padding: .7rem .9rem; box-shadow: var(--shadow); transition: border-color .15s, transform .12s;
}
ul.items a:hover { border-color: var(--accent); transform: translateX(3px); }
ul.items .num { font-size: .74rem; font-weight: 700; color: var(--accent-ink); font-variant-numeric: tabular-nums; min-width: 2.6rem; }
ul.items .t { font-weight: 600; }
ul.items .d { color: var(--ink-soft); font-size: .9rem; }

.foot-nav {
  margin-top: 3rem; padding-top: 1.2rem; border-top: 2px solid var(--line);
  font-size: .9rem; color: var(--ink-soft);
}
.foot-nav a { font-weight: 600; }

@media print {
  body { background: #fff; padding: 0; }
  a.card, ul.items a { box-shadow: none; }
}