/* Smoke & Signal: an air-quality bulletin on hazy paper. */
:root {
  color-scheme: light;
  --paper: #f3eee4;
  --paper-2: #ebe4d6;
  --card: #fbf8f2;
  --ink: #1b1915;
  --ink-2: #4f4a40;
  --muted: #847d70;
  --rule: #d8cfbe;
  --accent: #c4561d;          /* smoke / fire */
  --accent-soft: #f2d5c2;
  --blue: #2a6fb8;            /* without fires */
  --aqua: #178f68;            /* persistence */
  --shadow: 0 1px 0 #fff8 inset, 0 10px 30px -18px #3b2a1466;
  /* CPCB PM2.5 category colours */
  --c-good: #2e8b3a; --c-satisfactory: #8cbf3f; --c-moderate: #e3c21a;
  --c-poor: #ee8a1b; --c-very-poor: #d9352b; --c-severe: #8a1c1c;
  --display: "Instrument Serif", "Iowan Old Style", Georgia, serif;
  --sans: "IBM Plex Sans", "Segoe UI", sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, monospace;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --paper: #16130f; --paper-2: #1e1a15; --card: #1f1b16; --ink: #f0ebe1; --ink-2: #c9c1b2;
    --muted: #8f8778; --rule: #3a342b; --accent: #e47a3f; --accent-soft: #4a2a19;
    --blue: #5b9be0; --aqua: #34b98a; --shadow: 0 10px 30px -18px #000;
  }
}
:root[data-theme="dark"] {
  color-scheme: dark;
  --paper: #16130f; --paper-2: #1e1a15; --card: #1f1b16; --ink: #f0ebe1; --ink-2: #c9c1b2;
  --muted: #8f8778; --rule: #3a342b; --accent: #e47a3f; --accent-soft: #4a2a19;
  --blue: #5b9be0; --aqua: #34b98a; --shadow: 0 10px 30px -18px #000;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 72px; }
body {
  margin: 0; background: var(--paper); color: var(--ink);
  font: 15px/1.6 var(--sans); -webkit-font-smoothing: antialiased;
}
.haze {
  position: fixed; inset: 0; z-index: -1; pointer-events: none;
  background:
    radial-gradient(60vw 40vh at 85% -5%, color-mix(in srgb, var(--accent) 22%, transparent), transparent 70%),
    radial-gradient(50vw 50vh at -10% 30%, color-mix(in srgb, var(--muted) 18%, transparent), transparent 70%),
    url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='160' height='160'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.85' numOctaves='3'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='.06'/%3E%3C/svg%3E");
}
a { color: var(--accent); text-underline-offset: 3px; }
code { font: 0.88em var(--mono); background: var(--paper-2); padding: 1px 5px; border-radius: 4px; }
b, strong { font-weight: 600; }
.muted { color: var(--muted); font-weight: 400; }

/* ---------------------------------------------------------------- top bar */
.topbar {
  position: sticky; top: 0; z-index: 10; display: flex; align-items: center; justify-content: space-between;
  gap: 16px; padding: 12px clamp(16px, 4vw, 48px);
  background: color-mix(in srgb, var(--paper) 82%, transparent); backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--rule);
}
.brand { font: 24px/1 var(--display); color: var(--ink); text-decoration: none; display: flex; align-items: center; gap: 10px; white-space: nowrap; }
.brand em { color: var(--accent); }
.dot { width: 12px; height: 12px; border-radius: 50%; background: var(--accent); box-shadow: 0 0 0 4px var(--accent-soft); }
.topbar nav { display: flex; gap: clamp(10px, 2vw, 26px); overflow-x: auto; }
.topbar nav a { color: var(--ink-2); text-decoration: none; font-size: 14px; white-space: nowrap; }
.topbar nav a:hover { color: var(--accent); }

main { max-width: 1240px; margin: 0 auto; padding: 0 clamp(16px, 4vw, 48px); }

/* ---------------------------------------------------------------- hero */
.hero { padding: clamp(40px, 8vw, 96px) 0 40px; }
.kicker { font: 500 12px/1 var(--mono); letter-spacing: .14em; text-transform: uppercase; color: var(--accent); margin: 0 0 22px; }
.hero h1 {
  font: 400 clamp(40px, 6.4vw, 84px)/1.0 var(--display); letter-spacing: -0.01em;
  margin: 0; max-width: 16ch; animation: rise .8s cubic-bezier(.2,.7,.2,1) both;
}
.hero h1 em { color: var(--accent); }
.lede { font-size: clamp(16px, 1.5vw, 19px); color: var(--ink-2); max-width: 62ch; margin: 28px 0; animation: rise .8s .12s both; }
.answer {
  display: grid; grid-template-columns: auto 1fr; gap: 18px; align-items: start; max-width: 860px;
  border-left: 3px solid var(--accent); padding: 4px 0 4px 20px; animation: rise .8s .24s both;
}
.answer-label { font: 500 12px/1.9 var(--mono); text-transform: uppercase; letter-spacing: .12em; color: var(--accent); }
.answer p { margin: 0; font: 400 clamp(19px, 2vw, 25px)/1.35 var(--display); }
.primer { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; margin: 40px 0 0; max-width: 1040px; animation: rise .8s .3s both; }
.primer div { border-top: 1px solid var(--rule); padding-top: 10px; }
.primer dt { font: 500 11.5px/1.4 var(--mono); text-transform: uppercase; letter-spacing: .1em; color: var(--accent); margin-bottom: 4px; }
.primer dd { margin: 0; font-size: 13.5px; color: var(--ink-2); line-height: 1.5; }
.stats-title { font: 400 clamp(24px, 2.6vw, 32px)/1.1 var(--display); margin: 52px 0 14px; }
.stats { display: flex; flex-direction: column; max-width: 1040px; background: var(--card); border: 1px solid var(--rule); border-radius: 14px; overflow: hidden; box-shadow: var(--shadow); animation: rise .8s .36s both; }
.stat { display: grid; grid-template-columns: minmax(150px, 230px) 1fr; gap: 28px; align-items: center; padding: 22px 26px; }
.stat + .stat { border-top: 1px solid var(--rule); }
.stat .v { font: 400 clamp(38px, 4.4vw, 56px)/1 var(--display); color: var(--accent); white-space: nowrap; }
.stat .t { font: 600 16px/1.3 var(--sans); margin: 0 0 4px; }
.stat .l { font-size: 14px; color: var(--ink-2); margin: 0; line-height: 1.55; max-width: 70ch; }
fieldset > .hint { margin: -2px 0 10px; }
@keyframes rise { from { opacity: 0; transform: translateY(14px); } }

/* ---------------------------------------------------------------- blocks */
.block { padding: 64px 0 24px; border-top: 1px solid var(--rule); }
.block-head { display: grid; grid-template-columns: auto 1fr; gap: 22px; margin-bottom: 28px; }
.num { font: 400 64px/0.85 var(--display); color: var(--accent); opacity: .85; }
.block-head h2 { font: 400 clamp(32px, 4vw, 48px)/1.05 var(--display); margin: 0 0 6px; }
.block-head p { margin: 0; color: var(--ink-2); max-width: 70ch; }
h3 { font: 600 15px/1.3 var(--sans); margin: 0 0 10px; }
h3.sec { font: 400 26px/1.2 var(--display); margin: 40px 0 14px; }
.card { background: var(--card); border: 1px solid var(--rule); border-radius: 14px; padding: 20px; box-shadow: var(--shadow); }
.card + .card { margin-top: 16px; }
.note { font-size: 13px; color: var(--muted); margin: 12px 0 0; }
.sub { margin: -4px 0 10px; color: var(--ink-2); font-size: 14px; }
.two { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin-top: 24px; }

/* ---------------------------------------------------------------- forecast */
.forecast-grid { display: grid; grid-template-columns: minmax(340px, 5fr) 7fr; gap: 20px; align-items: start; }
.inputs { position: sticky; top: 76px; max-height: calc(100vh - 92px); overflow-y: auto; }
fieldset { border: 0; padding: 0; margin: 0 0 20px; }
legend { font: 500 11px/1 var(--mono); text-transform: uppercase; letter-spacing: .12em; color: var(--ink-2); margin-bottom: 10px; padding: 0; }
.presets { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 12px; }
.chip {
  font: 13px/1 var(--sans); padding: 7px 11px; border-radius: 999px; cursor: pointer;
  border: 1px solid var(--rule); background: var(--paper); color: var(--ink);
}
.chip:hover, .chip[aria-pressed="true"] { border-color: var(--accent); color: var(--accent); background: var(--accent-soft); }
.row { display: flex; gap: 10px; align-items: end; }
.grow { flex: 1; }
.field { display: flex; flex-direction: column; gap: 4px; font-size: 12.5px; color: var(--ink-2); }
.unit { font: 11px var(--mono); color: var(--muted); }
.unit b { color: var(--accent); font-weight: 500; }
input {
  font: 15px var(--mono); color: var(--ink); background: var(--paper); width: 100%;
  border: 1px solid var(--rule); border-radius: 8px; padding: 8px 9px; min-width: 0;
}
input:focus { outline: 2px solid var(--accent); outline-offset: -1px; border-color: transparent; }
input:invalid { border-color: var(--c-very-poor); }
.fields { display: grid; gap: 10px; }
.fields.three { grid-template-columns: repeat(3, 1fr); }
.week { display: grid; grid-template-columns: 56px repeat(7, 1fr); gap: 5px; align-items: center; font-size: 12px; }
.week .h { font: 10.5px/1.2 var(--mono); color: var(--muted); text-align: center; }
.week .h.today { color: var(--accent); font-weight: 500; }
.week .rl { font-size: 12px; color: var(--ink-2); }
.week input { padding: 7px 4px; text-align: center; font-size: 13px; }
.hint { font-size: 12.5px; color: var(--muted); margin: 8px 0 0; min-height: 1em; }
.btn { font: 500 14px var(--sans); border-radius: 8px; padding: 9px 14px; cursor: pointer; border: 1px solid var(--accent); background: var(--accent); color: #fff; white-space: nowrap; }
.btn.ghost { background: transparent; color: var(--accent); }
.btn:hover { filter: brightness(1.08); }
.error { color: var(--c-very-poor); font-size: 13px; margin: 0; min-height: 1em; }

.outputs { display: flex; flex-direction: column; gap: 16px; min-width: 0; }
.alert-banner { border-radius: 12px; padding: 12px 16px; font-size: 14px; display: flex; gap: 10px; align-items: center; border: 1px solid; }
.alert-banner.on { background: color-mix(in srgb, var(--c-severe) 12%, var(--card)); border-color: var(--c-severe); }
.alert-banner.off { background: var(--card); border-color: var(--rule); color: var(--ink-2); }
.alert-banner .icon { font: 600 13px var(--mono); padding: 3px 8px; border-radius: 6px; color: #fff; background: var(--c-severe); }
.alert-banner.off .icon { background: var(--muted); }
.alert-banner small { display: block; font-size: 12.5px; margin-top: 2px; }
.horizons { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; }
.hz { background: var(--card); border: 1px solid var(--rule); border-radius: 14px; padding: 16px 16px 14px; position: relative; overflow: hidden; box-shadow: var(--shadow); transition: transform .2s; }
.hz::before { content: ""; position: absolute; inset: 0 0 auto 0; height: 5px; background: var(--cat, var(--rule)); }
.hz .when { font: 11px var(--mono); color: var(--muted); text-transform: uppercase; letter-spacing: .08em; }
.hz .date { font-size: 13px; color: var(--ink-2); }
.hz .big { font: 400 54px/1 var(--display); margin: 10px 0 2px; font-variant-numeric: tabular-nums; }
.hz .big small { font: 12px var(--mono); color: var(--muted); margin-left: 4px; }
.cat { display: inline-flex; align-items: center; gap: 6px; font: 500 12px var(--sans); padding: 3px 9px 3px 7px; border-radius: 999px; background: color-mix(in srgb, var(--cat) 16%, var(--card)); border: 1px solid color-mix(in srgb, var(--cat) 55%, transparent); }
.cat::before { content: ""; width: 8px; height: 8px; border-radius: 50%; background: var(--cat); }
.hz .obs { font: 12.5px var(--mono); color: var(--ink-2); margin-top: 10px; border-top: 1px dashed var(--rule); padding-top: 8px; }
.hz .obs b { color: var(--ink); }
.loading .hz .big { opacity: .35; }
.chart svg { width: 100%; height: auto; display: block; }
.chart text { font: 11px var(--mono); fill: var(--muted); }
.chart .lbl { fill: var(--ink-2); }

/* ---------------------------------------------------------------- tables */
.table-wrap { overflow-x: auto; }
table.data { border-collapse: collapse; width: 100%; font-size: 13.5px; }
table.data th { font: 500 11px var(--mono); text-transform: uppercase; letter-spacing: .06em; color: var(--muted); text-align: left; padding: 8px 10px; border-bottom: 1px solid var(--rule); white-space: nowrap; }
table.data td { padding: 7px 10px; border-bottom: 1px solid color-mix(in srgb, var(--rule) 60%, transparent); white-space: nowrap; }
table.data td.n { font-family: var(--mono); text-align: right; font-variant-numeric: tabular-nums; }
table.data th.n { text-align: right; }
table.data tr.best td { background: color-mix(in srgb, var(--accent) 8%, transparent); }
table.data tr.best td:first-child { box-shadow: inset 3px 0 var(--accent); }
.pos { color: var(--c-good); } .neg { color: var(--c-very-poor); }
.tag { font: 10.5px var(--mono); padding: 1px 6px; border-radius: 4px; background: var(--paper-2); color: var(--ink-2); margin-left: 6px; }
.tag.fire { background: var(--accent-soft); color: var(--accent); }

/* ---------------------------------------------------------------- findings */
.goals { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; }
.goal { background: var(--card); border: 1px solid var(--rule); border-radius: 14px; padding: 18px; box-shadow: var(--shadow); }
.goal .gid { font: 400 34px/1 var(--display); }
.goal .verdict { float: right; font: 600 11px var(--mono); text-transform: uppercase; letter-spacing: .08em; padding: 4px 8px; border-radius: 6px; }
.verdict.met { background: color-mix(in srgb, var(--c-good) 18%, var(--card)); color: var(--c-good); }
.verdict.not { background: color-mix(in srgb, var(--c-very-poor) 14%, var(--card)); color: var(--c-very-poor); }
.verdict.partial { background: color-mix(in srgb, var(--c-poor) 18%, var(--card)); color: color-mix(in srgb, var(--c-poor) 70%, var(--ink)); }
.goal h4 { margin: 10px 0 6px; font-size: 15px; }
.goal p { margin: 0; color: var(--ink-2); font-size: 14px; }
.goal .kv { font: 13px var(--mono); margin-top: 10px; color: var(--ink); }
.gallery { display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 16px; }
.fig { background: var(--card); border: 1px solid var(--rule); border-radius: 14px; overflow: hidden; cursor: zoom-in; display: flex; flex-direction: column; text-align: left; padding: 0; color: inherit; font: inherit; box-shadow: var(--shadow); transition: transform .2s, box-shadow .2s; }
.fig:hover { transform: translateY(-2px); box-shadow: 0 16px 34px -20px #3b2a1488; }
.fig img { width: 100%; aspect-ratio: 16/10; object-fit: contain; background: #fff; border-bottom: 1px solid var(--rule); }
.fig div { padding: 12px 14px 14px; }
.fig b { display: block; font-size: 14px; margin-bottom: 4px; }
.fig span { font-size: 13px; color: var(--ink-2); }

/* ---------------------------------------------------------------- data & method */
.clean-stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; margin-top: 18px; }
.clean-stats div { border-top: 2px solid var(--accent); padding-top: 8px; }
.clean-stats b { font: 400 28px/1 var(--display); display: block; }
.clean-stats span { font-size: 12.5px; color: var(--ink-2); }
.pipeline { list-style: none; padding: 0; margin: 0; display: grid; grid-template-columns: repeat(4, 1fr); gap: 10px; counter-reset: s; }
.pipeline li { counter-increment: s; background: var(--card); border: 1px solid var(--rule); border-radius: 12px; padding: 14px; position: relative; }
.pipeline li::before { content: counter(s, decimal-leading-zero); font: 11px var(--mono); color: var(--accent); display: block; margin-bottom: 4px; }
.pipeline b { display: block; }
.pipeline span { font-size: 13px; color: var(--ink-2); }
.timeline { display: flex; gap: 4px; margin-top: 4px; }
.seg { flex: 1; padding: 14px; border-radius: 10px; color: #fff; min-width: 0; }
.seg b { display: block; font: 400 22px/1 var(--display); }
.seg span { font: 12px var(--mono); opacity: .9; }
.seg.train { background: #5d564a; } .seg.val { background: var(--blue); } .seg.test { background: var(--accent); }
.seg.extra { background: repeating-linear-gradient(45deg, #8f8778, #8f8778 6px, #a39b8c 6px, #a39b8c 12px); }
dl.feat { margin: 0; display: grid; grid-template-columns: 110px 1fr; gap: 8px 12px; font-size: 13px; }
dl.feat dt { font: 500 11px var(--mono); text-transform: uppercase; color: var(--muted); padding-top: 3px; }
dl.feat dt.fire { color: var(--accent); }
dl.feat dd { margin: 0; display: flex; flex-wrap: wrap; gap: 4px; }
dl.feat dd code { font-size: 11.5px; }
.downloads { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; margin-bottom: 16px; }
.dl { background: var(--card); border: 1px solid var(--rule); border-radius: 12px; padding: 16px; text-decoration: none; color: var(--ink); transition: border-color .2s; }
.dl:hover { border-color: var(--accent); }
.dl b { font: 400 24px/1.1 var(--display); display: block; }
.dl span { font: 12px var(--mono); color: var(--muted); }
.limits ul { margin: 0; padding-left: 18px; color: var(--ink-2); }
.limits li { margin: 6px 0; }
.foot { display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; padding: 28px clamp(16px, 4vw, 48px); border-top: 1px solid var(--rule); color: var(--muted); font-size: 13px; margin-top: 48px; }

dialog#lightbox { border: 0; border-radius: 14px; padding: 16px; max-width: min(1200px, 94vw); background: var(--card); color: var(--ink); }
dialog#lightbox::backdrop { background: #0009; backdrop-filter: blur(3px); }
dialog#lightbox img { width: 100%; background: #fff; border-radius: 8px; }
dialog#lightbox p { margin: 10px 4px 0; color: var(--ink-2); }
dialog .close { position: absolute; right: 10px; top: 6px; background: none; border: 0; font-size: 28px; color: var(--ink); cursor: pointer; }

/* ---------------------------------------------------------------- responsive */
@media (max-width: 1000px) {
  .forecast-grid { grid-template-columns: 1fr; }
  .inputs { position: static; max-height: none; }
  .pipeline { grid-template-columns: repeat(2, 1fr); }
  .two { grid-template-columns: 1fr; }
  .goals { grid-template-columns: 1fr; }
}
@media (max-width: 720px) {
  .goals, .downloads, .clean-stats, .primer { grid-template-columns: 1fr 1fr; }
  .stat { grid-template-columns: 1fr; gap: 8px; padding: 18px; }
  .horizons { grid-template-columns: 1fr; }
  .fields.three { grid-template-columns: 1fr 1fr; }
  .answer { grid-template-columns: 1fr; gap: 6px; }
  .topbar nav { display: none; }
  .gallery { grid-template-columns: 1fr; }
  .week { grid-template-columns: 44px repeat(7, 1fr); gap: 3px; }
  .week input { font-size: 11px; padding: 6px 1px; }
  .timeline { flex-wrap: wrap; } .seg { flex: 1 1 40% !important; }
  .num { font-size: 44px; }
}
@media (prefers-reduced-motion: reduce) { * { animation: none !important; transition: none !important; } }

/* number inputs: no spinner arrows (they steal width in the 7-day grid) */
input[type=number] { -moz-appearance: textfield; appearance: textfield; }
input[type=number]::-webkit-inner-spin-button, input[type=number]::-webkit-outer-spin-button { -webkit-appearance: none; margin: 0; }

/* grid children must be allowed to shrink below their content width */
.two > *, .forecast-grid > *, .goals > *, .gallery > * { min-width: 0; }
dl.feat dd code { overflow-wrap: anywhere; }
@media (max-width: 720px) { dl.feat { grid-template-columns: 1fr; gap: 4px; } dl.feat dd { margin-bottom: 8px; } }