/* ============================================================================
   FreeStack — clean light docs theme (with dark mode)
   ========================================================================== */
:root {
  --bg:            #ffffff;
  --bg-subtle:     #f7f8fa;
  --bg-elevated:   #ffffff;
  --border:        #e6e8eb;
  --border-strong: #d4d7dc;
  --text:          #1a1d21;
  --text-muted:    #5b626b;
  --text-faint:    #868d96;
  --accent:        #2f6df6;
  --accent-soft:   #eaf1ff;
  --accent-text:   #1d4ed8;
  --ok:            #0d8a4a;
  --ok-soft:       #e7f6ee;
  --warn:          #b25e00;
  --warn-soft:     #fdf0e1;
  --danger:        #c2351b;
  --danger-soft:   #fdeceA;
  --purple:        #7c3aed;
  --shadow:        0 1px 2px rgba(16,24,40,.04), 0 4px 12px rgba(16,24,40,.06);
  --shadow-lg:     0 8px 28px rgba(16,24,40,.10);
  --radius:        12px;
  --radius-sm:     8px;
  --mono: ui-monospace, "SF Mono", "JetBrains Mono", "Cascadia Code", Menlo, Consolas, monospace;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Inter, system-ui, sans-serif;
}
[data-theme="dark"] {
  --bg:            #0e1116;
  --bg-subtle:     #151a21;
  --bg-elevated:   #161b22;
  --border:        #232a33;
  --border-strong: #303843;
  --text:          #e6e9ee;
  --text-muted:    #98a1ad;
  --text-faint:    #6b7480;
  --accent:        #4f86ff;
  --accent-soft:   #16233f;
  --accent-text:   #8fb4ff;
  --ok:            #3fcf8e;
  --ok-soft:       #11271d;
  --warn:          #e8a14d;
  --warn-soft:     #2a2012;
  --danger:        #f08a76;
  --danger-soft:   #2c1714;
  --purple:        #a78bfa;
  --shadow:        0 1px 2px rgba(0,0,0,.3), 0 4px 12px rgba(0,0,0,.3);
  --shadow-lg:     0 8px 28px rgba(0,0,0,.45);
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0; font-family: var(--sans); background: var(--bg); color: var(--text);
  line-height: 1.55; -webkit-font-smoothing: antialiased; font-size: 15px;
}
a { color: var(--accent-text); text-decoration: none; }
a:hover { text-decoration: underline; }
h1,h2,h3,h4 { line-height: 1.25; font-weight: 680; letter-spacing: -.01em; }
code { font-family: var(--mono); font-size: .86em; }
::selection { background: var(--accent-soft); }

/* ---------- Layout ---------- */
.container { max-width: 1180px; margin: 0 auto; padding: 0 24px; }
.wrap { max-width: 1180px; margin: 0 auto; padding: 40px 24px 80px; }

/* ---------- Top nav ---------- */
header.nav {
  position: sticky; top: 0; z-index: 50; background: color-mix(in srgb, var(--bg) 86%, transparent);
  backdrop-filter: saturate(180%) blur(10px); border-bottom: 1px solid var(--border);
}
.nav-inner { display: flex; align-items: center; gap: 8px; height: 60px; }
.brand { display: flex; align-items: center; gap: 9px; font-weight: 740; font-size: 17px; color: var(--text); letter-spacing: -.02em; }
.brand:hover { text-decoration: none; }
.brand .logo {
  width: 26px; height: 26px; border-radius: 7px; display: grid; place-items: center;
  background: linear-gradient(135deg, var(--accent), var(--purple)); color: #fff; font-size: 15px; font-weight: 800;
}
.brand .tag { font-size: 11px; font-weight: 600; color: var(--text-faint); border: 1px solid var(--border); padding: 1px 6px; border-radius: 20px; }
.nav-links { display: flex; gap: 2px; margin-left: 18px; }
.nav-links a {
  color: var(--text-muted); padding: 7px 12px; border-radius: 8px; font-weight: 560; font-size: 14px;
}
.nav-links a:hover { background: var(--bg-subtle); color: var(--text); text-decoration: none; }
.nav-links a.active { color: var(--accent-text); background: var(--accent-soft); }
.nav-right { margin-left: auto; display: flex; align-items: center; gap: 8px; }
.icon-btn {
  width: 36px; height: 36px; border: 1px solid var(--border); background: var(--bg-elevated); color: var(--text-muted);
  border-radius: 9px; cursor: pointer; display: grid; place-items: center; font-size: 16px; transition: .15s;
}
.icon-btn:hover { background: var(--bg-subtle); color: var(--text); border-color: var(--border-strong); }
.menu-toggle { display: none; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex; align-items: center; gap: 7px; padding: 9px 16px; border-radius: 9px; font-weight: 600;
  font-size: 14px; cursor: pointer; border: 1px solid var(--border-strong); background: var(--bg-elevated); color: var(--text);
  transition: .15s; white-space: nowrap;
}
.btn:hover { background: var(--bg-subtle); text-decoration: none; }
.btn.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
.btn.primary:hover { filter: brightness(1.06); }
.btn.ghost { border-color: transparent; background: transparent; color: var(--text-muted); }
.btn.lg { padding: 12px 22px; font-size: 15px; }

/* ---------- Hero ---------- */
.hero { padding: 72px 0 28px; text-align: center; }
.hero .eyebrow {
  display: inline-flex; align-items: center; gap: 8px; font-size: 13px; font-weight: 600; color: var(--accent-text);
  background: var(--accent-soft); padding: 5px 13px; border-radius: 20px; margin-bottom: 22px;
}
.hero h1 { font-size: clamp(34px, 5vw, 52px); margin: 0 0 18px; letter-spacing: -.03em; }
.hero h1 .grad { background: linear-gradient(120deg, var(--accent), var(--purple)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.hero p.lead { font-size: clamp(16px, 2vw, 19px); color: var(--text-muted); max-width: 640px; margin: 0 auto 28px; }
.hero-cta { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }
.stat-row { display: flex; gap: 36px; justify-content: center; flex-wrap: wrap; margin-top: 52px; }
.stat { text-align: center; }
.stat .num { font-size: 30px; font-weight: 760; letter-spacing: -.02em; background: linear-gradient(120deg, var(--accent), var(--purple)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.stat .lbl { font-size: 13px; color: var(--text-faint); margin-top: 2px; }

/* ---------- Section headings ---------- */
.section-head { margin: 56px 0 22px; }
.section-head.first { margin-top: 8px; }
.section-head h2 { font-size: 26px; margin: 0 0 6px; }
.section-head p { color: var(--text-muted); margin: 0; max-width: 640px; }
.kicker { font-size: 12px; font-weight: 700; letter-spacing: .08em; text-transform: uppercase; color: var(--accent-text); margin-bottom: 8px; }

/* ---------- Cards grid ---------- */
.grid { display: grid; gap: 16px; }
.grid.cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid.cols-2 { grid-template-columns: repeat(2, 1fr); }
.grid.cols-4 { grid-template-columns: repeat(4, 1fr); }

.card {
  background: var(--bg-elevated); border: 1px solid var(--border); border-radius: var(--radius); padding: 20px;
  box-shadow: var(--shadow); transition: .18s; position: relative;
}
.card.link:hover { border-color: var(--border-strong); box-shadow: var(--shadow-lg); transform: translateY(-2px); }
.card h3 { margin: 0 0 6px; font-size: 17px; }
.card .icon-lg { font-size: 22px; margin-bottom: 12px; display: block; }
.card p { margin: 0; color: var(--text-muted); font-size: 14px; }
.card .arrow { color: var(--accent-text); font-weight: 600; font-size: 14px; margin-top: 14px; display: inline-block; }

/* ---------- Badges / pills ---------- */
.pill {
  display: inline-flex; align-items: center; gap: 5px; font-size: 11.5px; font-weight: 600; padding: 3px 9px;
  border-radius: 20px; border: 1px solid var(--border); color: var(--text-muted); background: var(--bg-subtle); white-space: nowrap;
}
.pill.ok    { color: var(--ok); background: var(--ok-soft); border-color: transparent; }
.pill.warn  { color: var(--warn); background: var(--warn-soft); border-color: transparent; }
.pill.acc   { color: var(--accent-text); background: var(--accent-soft); border-color: transparent; }
.pill.purple{ color: var(--purple); background: color-mix(in srgb, var(--purple) 13%, transparent); border-color: transparent; }
.pill.dot::before { content: ""; width: 6px; height: 6px; border-radius: 50%; background: currentColor; }

/* ---------- Tech tables ---------- */
.toolbar { display: flex; gap: 10px; flex-wrap: wrap; align-items: center; margin-bottom: 18px; }
.search-box {
  display: flex; align-items: center; gap: 8px; flex: 1; min-width: 220px; background: var(--bg-elevated);
  border: 1px solid var(--border); border-radius: 10px; padding: 0 12px;
}
.search-box input { border: 0; outline: 0; background: transparent; color: var(--text); padding: 11px 0; flex: 1; font-size: 14px; font-family: inherit; }
.search-box .ic { color: var(--text-faint); }
.chips { display: flex; gap: 7px; flex-wrap: wrap; }
.chip {
  font-size: 13px; font-weight: 560; padding: 7px 13px; border-radius: 20px; border: 1px solid var(--border);
  background: var(--bg-elevated); color: var(--text-muted); cursor: pointer; transition: .14s; white-space: nowrap;
}
.chip:hover { border-color: var(--border-strong); color: var(--text); }
.chip.active { background: var(--accent); border-color: var(--accent); color: #fff; }

.cat-block { margin-bottom: 38px; scroll-margin-top: 80px; }
.cat-block > .cat-title { display: flex; align-items: center; gap: 10px; margin: 0 0 4px; font-size: 19px; }
.cat-block > .cat-desc { color: var(--text-muted); font-size: 14px; margin: 0 0 16px; }

.table-wrap { overflow-x: auto; border: 1px solid var(--border); border-radius: var(--radius); background: var(--bg-elevated); box-shadow: var(--shadow); }
table.tech { width: 100%; border-collapse: collapse; font-size: 14px; min-width: 760px; }
table.tech th {
  text-align: left; font-size: 11.5px; text-transform: uppercase; letter-spacing: .04em; color: var(--text-faint);
  font-weight: 700; padding: 12px 16px; border-bottom: 1px solid var(--border); background: var(--bg-subtle); position: sticky; top: 0;
}
table.tech td { padding: 14px 16px; border-bottom: 1px solid var(--border); vertical-align: top; }
table.tech tr:last-child td { border-bottom: 0; }
table.tech tbody tr:hover { background: var(--bg-subtle); }
.tname { font-weight: 650; color: var(--text); display: flex; align-items: center; gap: 8px; }
.tname .star { color: var(--warn); font-size: 12px; }
.tblurb { color: var(--text-muted); font-size: 13px; margin-top: 3px; max-width: 420px; }
.tlimits { font-family: var(--mono); font-size: 12px; color: var(--text-muted); }
.tlimits b { color: var(--text); font-weight: 600; }
.twhy { color: var(--text-muted); font-size: 13px; }
.tlink { font-size: 13px; font-weight: 600; }
.watch { color: var(--warn); font-size: 12.5px; margin-top: 6px; display: flex; gap: 5px; }

/* ---------- Builder ---------- */
.builder-layout { display: grid; grid-template-columns: 1fr 380px; gap: 28px; align-items: start; }
.slot-group { margin-bottom: 26px; }
.slot-group h3 { font-size: 13px; text-transform: uppercase; letter-spacing: .05em; color: var(--text-faint); margin: 0 0 12px; }
.slot { background: var(--bg-elevated); border: 1px solid var(--border); border-radius: var(--radius); padding: 14px 16px; margin-bottom: 10px; box-shadow: var(--shadow); }
.slot-head { display: flex; align-items: center; gap: 10px; margin-bottom: 4px; }
.slot-head .ic { font-size: 17px; }
.slot-head .nm { font-weight: 640; font-size: 14.5px; }
.slot-head .opt { font-size: 11px; color: var(--text-faint); border: 1px solid var(--border); padding: 1px 6px; border-radius: 10px; margin-left: auto; }
.slot-desc { font-size: 12.5px; color: var(--text-faint); margin: 0 0 11px; }
.slot select {
  width: 100%; padding: 10px 12px; border-radius: 9px; border: 1px solid var(--border-strong); background: var(--bg);
  color: var(--text); font-size: 14px; font-family: inherit; cursor: pointer; appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%23868d96' stroke-width='3'%3E%3Cpath d='M6 9l6 6 6-6'/%3E%3C/svg%3E");
  background-repeat: no-repeat; background-position: right 12px center;
}
.slot select:focus { outline: 2px solid var(--accent-soft); border-color: var(--accent); }
.slot-meta { display: flex; gap: 6px; flex-wrap: wrap; margin-top: 10px; min-height: 4px; }

.summary {
  position: sticky; top: 80px; background: var(--bg-elevated); border: 1px solid var(--border); border-radius: var(--radius);
  box-shadow: var(--shadow-lg); overflow: hidden;
}
.summary-head { padding: 18px 20px; border-bottom: 1px solid var(--border); background: linear-gradient(135deg, var(--accent-soft), transparent); }
.summary-head h3 { margin: 0; font-size: 17px; }
.summary-head p { margin: 4px 0 0; font-size: 13px; color: var(--text-muted); }
.summary-body { padding: 18px 20px; }
.cost-big { font-size: 34px; font-weight: 780; letter-spacing: -.02em; }
.cost-big .per { font-size: 15px; color: var(--text-faint); font-weight: 500; }
.cost-sub { font-size: 13px; color: var(--text-muted); margin-top: 2px; }
.summary-list { margin: 18px 0 0; padding: 0; list-style: none; }
.summary-list li { display: flex; justify-content: space-between; gap: 10px; padding: 8px 0; border-bottom: 1px dashed var(--border); font-size: 13px; }
.summary-list li:last-child { border-bottom: 0; }
.summary-list .k { color: var(--text-faint); }
.summary-list .v { color: var(--text); font-weight: 600; text-align: right; }
.flags { margin-top: 16px; display: grid; gap: 8px; }
.flag { font-size: 12.5px; padding: 9px 12px; border-radius: 9px; display: flex; gap: 8px; align-items: flex-start; }
.flag.warn { background: var(--warn-soft); color: var(--warn); }
.flag.ok   { background: var(--ok-soft); color: var(--ok); }
.flag.info { background: var(--accent-soft); color: var(--accent-text); }
.summary-actions { padding: 0 20px 20px; display: grid; gap: 8px; }

/* ---------- Preset stacks ---------- */
.stack-card { border: 1px solid var(--border); border-radius: var(--radius); background: var(--bg-elevated); box-shadow: var(--shadow); overflow: hidden; }
.stack-card .bar { height: 5px; }
.stack-body { padding: 22px 24px; }
.stack-body h3 { font-size: 21px; margin: 0 0 6px; }
.stack-body .tagline { color: var(--text-muted); margin: 0 0 16px; font-size: 14.5px; }
.stack-best { font-size: 13px; color: var(--text); background: var(--bg-subtle); border: 1px solid var(--border); border-radius: 9px; padding: 10px 12px; margin-bottom: 16px; }
.stack-best b { color: var(--accent-text); }
.stack-items { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 16px; }
.stack-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 20px 28px; margin-top: 8px; }
pre.arch {
  font-family: var(--mono); font-size: 12.5px; line-height: 1.65; background: var(--bg-subtle); border: 1px solid var(--border);
  border-radius: var(--radius-sm); padding: 16px; overflow-x: auto; color: var(--text-muted); margin: 0;
}
.stack-detail h4 { font-size: 12px; text-transform: uppercase; letter-spacing: .05em; color: var(--text-faint); margin: 0 0 8px; }
.stack-detail p, .stack-detail li { font-size: 13.5px; color: var(--text-muted); }
.stack-detail ul { margin: 0; padding-left: 18px; }
.stack-detail ul li { margin-bottom: 5px; }
.ceiling { font-size: 13.5px; color: var(--text); background: var(--ok-soft); color: var(--ok); border-radius: 9px; padding: 10px 12px; }

/* ---------- Misc ---------- */
.note { background: var(--accent-soft); border: 1px solid color-mix(in srgb, var(--accent) 25%, transparent); border-radius: var(--radius); padding: 16px 18px; font-size: 14px; color: var(--text); display: flex; gap: 12px; }
.note .ic { font-size: 18px; }
.legend { display: flex; gap: 16px; flex-wrap: wrap; font-size: 13px; color: var(--text-muted); margin-top: 14px; }
.legend span { display: flex; align-items: center; gap: 6px; }
.empty { text-align: center; color: var(--text-faint); padding: 50px; font-size: 15px; }
footer.foot { border-top: 1px solid var(--border); padding: 30px 0; margin-top: 60px; color: var(--text-faint); font-size: 13px; }
.foot-inner { display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; align-items: center; }

/* ---------- Responsive ---------- */
@media (max-width: 960px) {
  .builder-layout { grid-template-columns: 1fr; }
  .summary { position: static; }
  .grid.cols-3, .grid.cols-4 { grid-template-columns: repeat(2, 1fr); }
  .stack-grid { grid-template-columns: 1fr; }
}
@media (max-width: 680px) {
  .nav-links { display: none; }
  .nav-links.open { display: flex; position: absolute; top: 60px; left: 0; right: 0; flex-direction: column; background: var(--bg-elevated); border-bottom: 1px solid var(--border); padding: 10px; margin: 0; gap: 4px; }
  .menu-toggle { display: grid; }
  .grid.cols-3, .grid.cols-4, .grid.cols-2 { grid-template-columns: 1fr; }
  .stat-row { gap: 24px; }
  .wrap { padding: 28px 18px 60px; }
}