/* Seminal AI — reference manual design system
   Concept: instrument panel / spec book. Data is the hero; colour encodes
   meaning (price tier, model status), never mood. */

/* ---------------------------------------------------------------- tokens */
:root {
  color-scheme: light dark;

  --paper:        #ECEFF1;
  --paper-raised: #F8FAFB;
  --paper-sunk:   #E2E7EA;
  --ink:          #0D1A21;
  --ink-2:        #45555E;
  --ink-3:        #54646D;
  --rule:         #C6D0D6;
  --rule-strong:  #97A6AE;

  --signal:       #0B6E75;
  --signal-soft:  #D6E9EA;
  --amber:        #8A5200;
  --amber-soft:   #F3E5CC;
  --rust:         #9C3A1E;
  --rust-soft:    #F1DCD5;
  --violet:       #52468A;
  --violet-soft:  #E1DEEE;

  /* price ramp — sequential, encodes $/Mtok tiers */
  --t0: #0B6E75; --t1: #4F8A5E; --t2: #8A8A32; --t3: #A96A16; --t4: #9C3A1E;

  --sans: "IBM Plex Sans", ui-sans-serif, system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  --rail: 16.5rem;
  --measure: 72ch;
  --pad: clamp(1rem, 3vw, 2.5rem);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper:        #0C1418;
    --paper-raised: #131E24;
    --paper-sunk:   #091014;
    --ink:          #DCE6EA;
    --ink-2:        #9DAFB8;
    --ink-3:        #8A9FAA;
    --rule:         #223038;
    --rule-strong:  #3A4C56;

    --signal:       #46B8BF;
    --signal-soft:  #0E2C2F;
    --amber:        #D08B21;
    --amber-soft:   #2C2110;
    --rust:         #D2664A;
    --rust-soft:    #2E1610;
    --violet:       #9A8DD6;
    --violet-soft:  #1C1930;

    --t0: #46B8BF; --t1: #74BA7F; --t2: #C2BE58; --t3: #D6912F; --t4: #D2664A;
  }
}

[data-theme="dark"] {
  --paper:        #0C1418;
  --paper-raised: #131E24;
  --paper-sunk:   #091014;
  --ink:          #DCE6EA;
  --ink-2:        #9DAFB8;
  --ink-3:        #8A9FAA;
  --rule:         #223038;
  --rule-strong:  #3A4C56;

  --signal:       #46B8BF;
  --signal-soft:  #0E2C2F;
  --amber:        #D08B21;
  --amber-soft:   #2C2110;
  --rust:         #D2664A;
  --rust-soft:    #2E1610;
  --violet:       #9A8DD6;
  --violet-soft:  #1C1930;

  --t0: #46B8BF; --t1: #74BA7F; --t2: #C2BE58; --t3: #D6912F; --t4: #D2664A;
}

/* ------------------------------------------------------------------ base */
*, *::before, *::after { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; }
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.6;
  font-feature-settings: "kern" 1;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 { font-weight: 600; line-height: 1.2; margin: 0 0 .5em; letter-spacing: -0.011em; }
h1 { font-size: clamp(1.9rem, 1.3rem + 2.4vw, 3rem); letter-spacing: -0.022em; }
h2 { font-size: clamp(1.35rem, 1.1rem + 1.1vw, 1.85rem); }
h3 { font-size: 1.16rem; }
h4 { font-size: 1rem; }
p  { margin: 0 0 1em; }

a { color: var(--signal); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 2px; }
a:focus-visible, button:focus-visible, input:focus-visible, select:focus-visible,
summary:focus-visible, [tabindex]:focus-visible {
  outline: 2px solid var(--signal);
  outline-offset: 2px;
  border-radius: 2px;
}

code, kbd, samp, .num { font-family: var(--mono); font-variant-numeric: tabular-nums; }
code { font-size: .875em; background: var(--paper-sunk); padding: .12em .35em; border-radius: 3px; }
pre { margin: 0 0 1.25rem; }
pre { overflow-x: auto; background: var(--paper-sunk); border: 1px solid var(--rule);
  border-radius: 4px; }
pre code { display: block; padding: 1rem 1.1rem; background: none; border: 0;
  line-height: 1.55; font-size: .84rem; }

hr { border: 0; border-top: 1px solid var(--rule); margin: 2.5rem 0; }
img { max-width: 100%; height: auto; }

.skip {
  position: absolute; left: -9999px; top: 0; z-index: 100;
  background: var(--ink); color: var(--paper); padding: .6rem 1rem;
}
.skip:focus { left: .5rem; top: .5rem; }

/* ---------------------------------------------------------------- shell */
.shell { display: grid; grid-template-columns: var(--rail) minmax(0, 1fr); min-height: 100vh; }

.rail {
  border-right: 1px solid var(--rule);
  background: var(--paper-raised);
  padding: 1.4rem 1.1rem 3rem;
  position: sticky; top: 0; height: 100vh; overflow-y: auto;
}

.brand { display: flex; align-items: baseline; gap: .55rem; margin-bottom: .25rem; }
.brand a { color: var(--ink); font-weight: 700; font-size: 1.12rem; letter-spacing: -0.02em; }
.brand a:hover { text-decoration: none; color: var(--signal); }
.brand .mark {
  font-family: var(--mono); font-size: .7rem; font-weight: 500;
  color: var(--signal); border: 1px solid var(--signal); border-radius: 2px;
  padding: .05rem .3rem; letter-spacing: .02em;
}
.rail .tagline { color: var(--ink-3); font-size: .78rem; line-height: 1.45; margin: 0 0 1.25rem; }

.railsearch { position: relative; margin-bottom: 1.25rem; }
.railsearch input {
  width: 100%; font-family: var(--sans); font-size: .84rem;
  padding: .48rem .6rem; color: var(--ink);
  background: var(--paper); border: 1px solid var(--rule); border-radius: 3px;
}
.railsearch input::placeholder { color: var(--ink-3); }

.railnav { font-size: .875rem; }
.railnav ol { list-style: none; margin: 0 0 1.35rem; padding: 0; }
.railnav li { margin: 0; }
.railnav .chapter {
  display: flex; gap: .5rem; align-items: baseline;
  padding: .24rem 0; color: var(--ink-2);
}
.railnav .chapter:hover { color: var(--signal); text-decoration: none; }
.railnav .chapter.here { color: var(--ink); font-weight: 600; }
.railnav .chapter.here .sec { color: var(--signal); }
.railnav .sec {
  font-family: var(--mono); font-size: .74rem; color: var(--ink-3);
  min-width: 1.9rem; font-variant-numeric: tabular-nums;
}
.railnav .grouplabel {
  font-size: .72rem; color: var(--ink-3); font-weight: 600;
  padding: .9rem 0 .3rem; border-bottom: 1px solid var(--rule); margin-bottom: .35rem;
}

.railfoot { margin-top: 2rem; padding-top: 1rem; border-top: 1px solid var(--rule);
  font-size: .74rem; color: var(--ink-3); line-height: 1.5; }
.railfoot a { color: var(--ink-2); }
.railfoot p { margin: 0 0 .5rem; }

.themebtn {
  font: inherit; font-size: .74rem; color: var(--ink-2); cursor: pointer;
  background: none; border: 1px solid var(--rule); border-radius: 3px;
  padding: .25rem .5rem; margin-top: .35rem;
}
.themebtn:hover { border-color: var(--signal); color: var(--signal); }

/* mobile rail */
.railtoggle { display: none; }
.topbar { display: none; }

@media (max-width: 900px) {
  .shell { grid-template-columns: minmax(0, 1fr); }
  .topbar {
    display: flex; align-items: center; justify-content: space-between; gap: 1rem;
    padding: .7rem var(--pad); border-bottom: 1px solid var(--rule);
    background: var(--paper-raised); position: sticky; top: 0; z-index: 20;
  }
  .rail {
    position: static; height: auto; border-right: 0; border-bottom: 1px solid var(--rule);
  }
  .rail[hidden] { display: none; }
  .railtoggle {
    display: inline-block; font: inherit; font-size: .82rem; cursor: pointer;
    background: none; color: var(--ink); border: 1px solid var(--rule-strong);
    border-radius: 3px; padding: .3rem .65rem;
  }
}

/* --------------------------------------------------------------- content */
main { padding: 0 0 5rem; min-width: 0; }
.wrap { padding: 2.4rem var(--pad) 0; }
.prose { max-width: var(--measure); }
.prose li { margin-bottom: .4rem; }
.prose ul, .prose ol { padding-left: 1.35rem; }

.pagehead { border-bottom: 2px solid var(--ink); padding-bottom: 1.1rem; margin-bottom: 1.9rem; }
.pagehead .sec {
  font-family: var(--mono); font-size: .78rem; color: var(--signal);
  font-variant-numeric: tabular-nums; display: block; margin-bottom: .35rem;
}
.pagehead .lede { font-size: 1.06rem; color: var(--ink-2); max-width: var(--measure); margin: .55rem 0 0; }

.asof {
  font-family: var(--mono); font-size: .72rem; color: var(--ink-3);
  margin-top: .8rem; display: block;
}

section.block { margin: 0 0 3.2rem; }
section.block > h2 { display: flex; align-items: baseline; gap: .6rem; }
section.block > h2 .sec {
  font-family: var(--mono); font-size: .8rem; color: var(--signal); font-weight: 500;
}

/* --------------------------------------------------------------- tables */
.tablewrap { overflow-x: auto; border: 1px solid var(--rule); border-radius: 4px; background: var(--paper-raised); }
table { border-collapse: collapse; width: 100%; font-size: .86rem; }
caption { text-align: left; font-size: .8rem; color: var(--ink-3); padding: .6rem .7rem; }
th, td { padding: .5rem .7rem; text-align: left; border-bottom: 1px solid var(--rule); vertical-align: top; }
thead th {
  position: sticky; top: 0; z-index: 2;
  background: var(--paper-sunk); color: var(--ink-2);
  font-weight: 600; font-size: .76rem; white-space: nowrap;
  border-bottom: 1px solid var(--rule-strong);
}
tbody tr:last-child td { border-bottom: 0; }
tbody tr:hover { background: var(--paper-sunk); }
td.n, th.n { text-align: right; font-family: var(--mono); font-variant-numeric: tabular-nums; white-space: nowrap; }
th.n { text-align: right; }
td.name { font-weight: 600; }
td.name a { color: var(--ink); }
td.name a:hover { color: var(--signal); }
.modelid { font-family: var(--mono); font-size: .74rem; color: var(--ink-3); display: block; font-weight: 400; }

th[data-sort] { cursor: pointer; user-select: none; }
th[data-sort]:hover { color: var(--signal); }
th[data-sort]::after { content: "\2195"; opacity: .3; margin-left: .3rem; font-size: .8em; }
th[data-sort][aria-sort="ascending"]::after  { content: "\2191"; opacity: 1; color: var(--signal); }
th[data-sort][aria-sort="descending"]::after { content: "\2193"; opacity: 1; color: var(--signal); }

/* price tier encoding */
.tier { border-left: 3px solid transparent; padding-left: .5rem; }
.tier-0 { border-left-color: var(--t0); }
.tier-1 { border-left-color: var(--t1); }
.tier-2 { border-left-color: var(--t2); }
.tier-3 { border-left-color: var(--t3); }
.tier-4 { border-left-color: var(--t4); }

/* --------------------------------------------------------------- badges */
.tag {
  display: inline-block; font-family: var(--mono); font-size: .68rem;
  padding: .1rem .38rem; border-radius: 2px; border: 1px solid transparent;
  white-space: nowrap; line-height: 1.5;
}
.tag-ga         { color: var(--signal); background: var(--signal-soft); border-color: var(--signal); }
.tag-preview,
.tag-beta       { color: var(--amber);  background: var(--amber-soft);  border-color: var(--amber); }
.tag-deprecated,
.tag-retired,
.tag-discontinued { color: var(--rust); background: var(--rust-soft); border-color: var(--rust); }
.tag-open       { color: var(--violet); background: var(--violet-soft); border-color: var(--violet); }
.tag-plain      { color: var(--ink-2);  background: var(--paper-sunk);  border-color: var(--rule); }
.tag-affiliate  { color: var(--amber);  background: var(--amber-soft);  border-color: var(--amber); }

.caps { display: flex; flex-wrap: wrap; gap: .25rem; }

/* ---------------------------------------------------------------- panels */
.grid { display: grid; background: var(--paper-raised); border: 1px solid var(--rule);
  border-radius: 4px; overflow: hidden; }
.grid-2 { grid-template-columns: repeat(auto-fit, minmax(20rem, 1fr)); }
.grid-3 { grid-template-columns: repeat(auto-fit, minmax(15rem, 1fr)); }
.cell { padding: 1.05rem 1.15rem; border-right: 1px solid var(--rule); border-bottom: 1px solid var(--rule); }
.cell h3 { margin-bottom: .3rem; font-size: 1rem; }
.cell h3 a { color: var(--ink); }
.cell h3 a:hover { color: var(--signal); }
.cell p { margin: 0; color: var(--ink-2); font-size: .875rem; }
.cell .meta { font-family: var(--mono); font-size: .72rem; color: var(--ink-3); margin-top: .55rem; display: block; }

.specs { display: grid; grid-template-columns: repeat(auto-fit, minmax(10rem, 1fr));
  background: var(--paper-raised); border: 1px solid var(--rule); border-radius: 4px;
  overflow: hidden; margin-bottom: 1.6rem; }
.spec { padding: .8rem .9rem; border-right: 1px solid var(--rule); border-bottom: 1px solid var(--rule); }
.spec dt { font-size: .72rem; color: var(--ink-3); margin-bottom: .2rem; }
.spec dd { margin: 0; font-family: var(--mono); font-size: 1.02rem; font-weight: 500;
  font-variant-numeric: tabular-nums; color: var(--ink); }
.spec dd small { font-family: var(--sans); font-size: .72rem; color: var(--ink-3); font-weight: 400; }

.note {
  border-left: 3px solid var(--signal); background: var(--signal-soft);
  padding: .85rem 1rem; margin: 0 0 1.5rem; font-size: .9rem; border-radius: 0 3px 3px 0;
}
.note.warn { border-left-color: var(--amber); background: var(--amber-soft); }
.note p:last-child { margin-bottom: 0; }
.note strong { font-weight: 600; }

/* -------------------------------------------------------------- controls */
.controls {
  display: flex; flex-wrap: wrap; gap: .6rem; align-items: center;
  margin-bottom: 1.1rem; padding: .85rem; background: var(--paper-raised);
  border: 1px solid var(--rule); border-radius: 4px;
}
.controls input[type="search"], .controls select {
  font-family: var(--sans); font-size: .84rem; padding: .4rem .55rem; color: var(--ink);
  background: var(--paper); border: 1px solid var(--rule); border-radius: 3px;
}
.controls input[type="search"] { flex: 1 1 14rem; min-width: 0; }
.controls label { font-size: .78rem; color: var(--ink-3); display: flex; align-items: center; gap: .35rem; }
.chip {
  font: inherit; font-size: .78rem; cursor: pointer; color: var(--ink-2);
  background: var(--paper); border: 1px solid var(--rule); border-radius: 999px;
  padding: .25rem .7rem;
}
.chip[aria-pressed="true"] { background: var(--signal); border-color: var(--signal); color: var(--paper-raised); }
[data-theme="dark"] .chip[aria-pressed="true"] { color: #08171A; }

.count { font-family: var(--mono); font-size: .76rem; color: var(--ink-3); margin-left: auto; }

.btn {
  display: inline-block; font: inherit; font-size: .85rem; cursor: pointer;
  padding: .48rem .95rem; border-radius: 3px;
  background: var(--ink); color: var(--paper); border: 1px solid var(--ink);
}
.btn:hover { background: var(--signal); border-color: var(--signal); color: var(--paper-raised); text-decoration: none; }
.btn.ghost { background: none; color: var(--ink); }
.btn.ghost:hover { color: var(--signal); background: none; }

/* ------------------------------------------------------------ calculator */
.calc { display: grid; grid-template-columns: repeat(auto-fit, minmax(11rem, 1fr)); gap: .9rem; margin-bottom: 1.2rem; }
.calc label { display: block; font-size: .76rem; color: var(--ink-3); margin-bottom: .25rem; }
.calc input, .calc select {
  width: 100%; font-family: var(--mono); font-size: .9rem; padding: .45rem .55rem; color: var(--ink);
  background: var(--paper-raised); border: 1px solid var(--rule); border-radius: 3px;
}

/* --------------------------------------------------------------- compare */
.cmpgrid { overflow-x: auto; }
.cmpgrid table { min-width: 40rem; }
.cmpgrid th:first-child, .cmpgrid td:first-child {
  position: sticky; left: 0; background: var(--paper-raised);
  border-right: 1px solid var(--rule); font-weight: 600; font-size: .8rem;
}
.cmpgrid thead th:first-child { background: var(--paper-sunk); z-index: 3; }
.diff { background: var(--signal-soft); }

/* ---------------------------------------------------------------- search */
.results { list-style: none; padding: 0; margin: 1rem 0 0; }
.results li { padding: .7rem 0; border-bottom: 1px solid var(--rule); }
.results .kind { font-family: var(--mono); font-size: .7rem; color: var(--ink-3); }
.results h3 { margin: .1rem 0 .2rem; font-size: 1rem; }
.results p { margin: 0; font-size: .85rem; color: var(--ink-2); }

/* ---------------------------------------------------------------- footer */
footer.pagefoot {
  border-top: 1px solid var(--rule); margin-top: 3rem;
  padding: 1.6rem var(--pad); font-size: .8rem; color: var(--ink-3);
}
footer.pagefoot a { color: var(--ink-2); }
footer.pagefoot p { margin: 0 0 .4rem; max-width: var(--measure); }
.flag { width: 1rem; vertical-align: -1px; }

/* ------------------------------------------------------------------ misc */
.srcnote { font-family: var(--mono); font-size: .72rem; color: var(--ink-3); }
.hide { display: none !important; }
.adslot { margin: 2rem 0; min-height: 0; }
.adslot:empty { display: none; }

/* ----------------------------------------------------------- submit form */
.submitform { max-width: 34rem; }
.fieldrow { margin-bottom: 1.1rem; }
.fieldrow label { display: block; font-size: .85rem; font-weight: 600; margin-bottom: .3rem; }
.fieldrow label small { font-weight: 400; color: var(--ink-3); }
.fieldrow input, .fieldrow textarea, .fieldrow select {
  width: 100%; font-family: var(--sans); font-size: .9rem; padding: .5rem .6rem;
  color: var(--ink); background: var(--paper-raised);
  border: 1px solid var(--rule); border-radius: 3px;
}
.fieldrow textarea { resize: vertical; }
.fieldrow .hint { font-size: .78rem; color: var(--ink-3); margin: .3rem 0 0; }


/* ------------------------------------------------- accessibility fixes */
/* Links inside running text need a non-colour cue to be distinguishable. */
.prose a, .note a, .pagefoot a, .cell p a, .srcnote a, .results p a, caption a {
  text-decoration: underline;
  text-underline-offset: 2px;
  text-decoration-thickness: 1px;
}
.prose a:hover, .note a:hover, .pagefoot a:hover { text-decoration-thickness: 2px; }

/* Regions that scroll must be reachable and operable by keyboard. */
.tablewrap:focus-visible, pre:focus-visible, .cmpgrid:focus-visible {
  outline: 2px solid var(--signal);
  outline-offset: 2px;
}

/* The provider line under a model title reads as running text to a11y tools. */
.pagehead + p a, .modelmeta a { text-decoration: underline; text-underline-offset: 2px; }

/* Index-page cells are the top-level items on their page, so they carry h2. */
.cell h2 { font-size: 1rem; margin-bottom: .3rem; line-height: 1.3; letter-spacing: 0; }
.cell h2 a { color: var(--ink); }
.cell h2 a:hover { color: var(--signal); }