/* =============================================================
   9MW1911 Yellow-Band Deviation Investigation — Site Stylesheet
   Design language: chromatogram bands, stainless-steel cleanroom,
   amber anomaly. Avoid template defaults.
   ============================================================= */

:root {
  /* Palette — grounded in the subject */
  --ink:        #0E1F2C;   /* near-black steel blue, primary text */
  --steel:      #2F4A5E;   /* steel blue, secondary headings */
  --mist:       #6E818F;   /* muted, captions / meta */
  --line:       #D3DCE3;   /* hairlines, table borders */
  --line-soft:  #E6ECF1;
  --paper:      #F2F5F8;   /* clean lab background */
  --card:       #FFFFFF;
  --amber:      #C48A2E;   /* the yellow band — the anomaly */
  --amber-soft: #F3E6CA;   /* wash for anomaly highlights */
  --rust:       #9E3F1F;   /* rust / iron */
  --clear:      #2E6F55;   /* resolved / cleared */
  --warn:       #B97A0A;
  --danger:     #B04B2A;

  /* Type scale (NOT viewport-scaled; fixed rem) */
  --fs-display: 2.4rem;
  --fs-h1:      1.85rem;
  --fs-h2:      1.30rem;
  --fs-h3:      1.05rem;
  --fs-body:    0.96rem;
  --fs-small:   0.84rem;
  --fs-micro:   0.74rem;

  /* Rhythm */
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 24px;
  --space-6: 32px;
  --space-7: 48px;
  --space-8: 72px;
  --radius:   4px;          /* keep restrained, 8px ceiling rule */

  --header-h: 56px;
  --sig-h:    44px;         /* signature chromatogram strip */
  --content-max: 1120px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: "Source Han Sans SC","Noto Sans SC","PingFang SC",
               "Microsoft YaHei","Helvetica Neue",Arial,sans-serif;
  font-size: var(--fs-body);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a { color: var(--steel); text-decoration: none; border-bottom: 1px solid var(--line); }
a:hover { color: var(--ink); border-bottom-color: var(--ink); }

img, svg { max-width: 100%; display: block; }

/* ---------- Top header strip ---------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: var(--card);
  border-bottom: 1px solid var(--line);
}
.site-header__inner {
  max-width: var(--content-max);
  margin: 0 auto;
  height: var(--header-h);
  display: flex; align-items: center; gap: var(--space-5);
  padding: 0 var(--space-5);
}
.brand {
  display: flex; align-items: center; gap: var(--space-3);
  border: none; color: var(--ink);
}
.brand img { width: 28px; height: auto; }
.brand__txt { line-height: 1.1; }
.brand__name {
  font-family: "Source Han Serif SC","Noto Serif SC","Songti SC","STSong","SimSun",serif;
  font-weight: 600; font-size: 1.02rem; letter-spacing: 0;
}
.brand__sub {
  color: var(--mist); font-size: var(--fs-micro);
  letter-spacing: 0.04em; text-transform: uppercase;
}
.site-nav {
  margin-left: auto;
  display: flex; gap: var(--space-4);
  overflow-x: auto; -ms-overflow-style: none; scrollbar-width: none;
}
.site-nav::-webkit-scrollbar { display: none; }
.site-nav a {
  border: none; padding: 6px 0;
  font-size: var(--fs-small); color: var(--steel);
  white-space: nowrap;
  position: relative;
}
.site-nav a .num {
  color: var(--amber); font-weight: 600; margin-right: 4px;
  font-family: "Source Han Serif SC","Noto Serif SC","Songti SC","STSong","SimSun",serif;
}
.site-nav a:hover, .site-nav a.is-active { color: var(--ink); }
.site-nav a.is-active::after {
  content: ""; position: absolute; left: 0; right: 0; bottom: -1px;
  height: 2px; background: var(--amber);
}

/* ---------- Signature chromatogram strip ---------- */
.sig {
  height: var(--sig-h);
  background: linear-gradient(180deg, #FAFCFD 0%, var(--paper) 100%);
  border-bottom: 1px solid var(--line);
  display: flex; align-items: center;
  position: relative; overflow: hidden;
}
.sig__inner {
  max-width: var(--content-max);
  width: 100%; margin: 0 auto;
  padding: 0 var(--space-5);
  display: flex; align-items: center; gap: var(--space-4);
}
.sig svg { width: 100%; height: 28px; }
.sig__label {
  font-size: var(--fs-micro);
  color: var(--mist);
  font-family: "Source Han Serif SC","Noto Serif SC","Songti SC","STSong","SimSun",serif;
  letter-spacing: 0.06em;
  white-space: nowrap;
}

/* ---------- Layout ---------- */
main { padding: var(--space-7) 0 var(--space-8); }
.container { max-width: var(--content-max); margin: 0 auto; padding: 0 var(--space-5); }

/* Eyebrow + page title */
.eyebrow {
  font-size: var(--fs-small);
  color: var(--amber);
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  font-family: "Source Han Serif SC","Noto Serif SC","Songti SC","STSong","SimSun",serif;
  display: inline-flex; align-items: center; gap: var(--space-2);
  margin-bottom: var(--space-3);
}
.eyebrow::before {
  content: ""; width: 24px; height: 1px; background: var(--amber);
}
h1.page-title {
  font-family: "Source Han Serif SC","Noto Serif SC","Songti SC","STSong","SimSun",serif;
  font-size: var(--fs-display); font-weight: 600;
  color: var(--ink);
  margin: 0 0 var(--space-4);
  line-height: 1.25; letter-spacing: 0;
}
h2.section {
  font-family: "Source Han Serif SC","Noto Serif SC","Songti SC","STSong","SimSun",serif;
  font-size: var(--fs-h1); font-weight: 600;
  color: var(--ink);
  margin: var(--space-7) 0 var(--space-4);
  display: flex; align-items: baseline; gap: var(--space-3);
  padding-bottom: var(--space-3);
  border-bottom: 1px solid var(--line);
}
h2.section .num {
  font-size: 0.85em; color: var(--amber); font-weight: 500;
  font-feature-settings: "tnum";
  flex-shrink: 0;
}
h3 {
  font-family: "Source Han Serif SC","Noto Serif SC","Songti SC","STSong","SimSun",serif;
  font-size: var(--fs-h2); font-weight: 600;
  color: var(--steel);
  margin: var(--space-6) 0 var(--space-3);
}
h4 {
  font-size: var(--fs-h3); font-weight: 600;
  color: var(--steel);
  margin: var(--space-5) 0 var(--space-2);
}

p { margin: 0 0 var(--space-4); }
.lede {
  font-size: 1.08rem; color: var(--steel);
  line-height: 1.7; max-width: 60ch;
  margin-bottom: var(--space-6);
}
.muted { color: var(--mist); }
.small { font-size: var(--fs-small); }
.mono { font-family: "JetBrains Mono","Consolas","Courier New",monospace; font-size: 0.92em; }
.tnum { font-variant-numeric: tabular-nums; }

/* ---------- Hero (index) ---------- */
.hero {
  padding: var(--space-7) 0 var(--space-6);
  border-bottom: 1px solid var(--line);
}
.hero__chrom {
  width: 100%; height: 200px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  margin-bottom: var(--space-6);
  position: relative; overflow: hidden;
}
.hero__chrom svg { width: 100%; height: 100%; display: block; }
.hero__caption {
  position: absolute; left: var(--space-3); top: var(--space-3);
  font-size: var(--fs-micro); color: var(--mist);
  font-family: "Source Han Serif SC","Noto Serif SC","Songti SC","STSong","SimSun",serif;
  letter-spacing: 0.08em;
}
.hero__legend {
  position: absolute; right: var(--space-3); bottom: var(--space-3);
  display: flex; gap: var(--space-4); font-size: var(--fs-micro); color: var(--mist);
}
.hero__legend .dot {
  display: inline-block; width: 8px; height: 8px; border-radius: 50%;
  margin-right: 4px; vertical-align: middle;
}

.hero__grid {
  display: grid; gap: var(--space-5);
  grid-template-columns: 1.4fr 1fr;
}
@media (max-width: 880px) { .hero__grid { grid-template-columns: 1fr; } }

.kpi-row {
  display: grid; gap: var(--space-3);
  grid-template-columns: repeat(4, 1fr);
}
@media (max-width: 720px) { .kpi-row { grid-template-columns: repeat(2, 1fr); } }
.kpi {
  background: var(--card);
  border: 1px solid var(--line);
  border-left: 3px solid var(--amber);
  padding: var(--space-4);
  border-radius: var(--radius);
}
.kpi__val {
  font-family: "Source Han Serif SC","Noto Serif SC","Songti SC","STSong","SimSun",serif;
  font-size: 1.7rem; font-weight: 600; color: var(--ink);
  line-height: 1.1; font-variant-numeric: tabular-nums;
}
.kpi__lab {
  font-size: var(--fs-micro); color: var(--mist);
  margin-top: 4px; letter-spacing: 0.04em;
}
.kpi--clear { border-left-color: var(--clear); }
.kpi--rust  { border-left-color: var(--rust); }
.kpi--steel { border-left-color: var(--steel); }

/* ---------- Cards / panels ---------- */
.panel {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--space-5);
}
.panel + .panel { margin-top: var(--space-5); }
.panel__title {
  font-family: "Source Han Serif SC","Noto Serif SC","Songti SC","STSong","SimSun",serif;
  font-size: 1.02rem; font-weight: 600; color: var(--ink);
  margin: 0 0 var(--space-3);
  display: flex; align-items: center; gap: var(--space-2);
}
.panel--anomaly { border-left: 3px solid var(--amber); }
.panel--resolved { border-left: 3px solid var(--clear); }
.panel--rust    { border-left: 3px solid var(--rust); }

.callout {
  background: var(--amber-soft);
  border-left: 3px solid var(--amber);
  padding: var(--space-4) var(--space-5);
  border-radius: 0 var(--radius) var(--radius) 0;
  margin: var(--space-5) 0;
  font-size: 0.96rem;
}
.callout strong { color: var(--warn); }

ul.checklist, ol.numbered {
  padding-left: 1.2em; margin: 0 0 var(--space-4);
}
ul.checklist li { list-style: none; position: relative; padding-left: 1.4em; margin-bottom: 6px; }
ul.checklist li::before {
  content: ""; position: absolute; left: 0; top: 0.6em;
  width: 10px; height: 1px; background: var(--amber);
}
ul.checklist li.is-done::before { background: var(--clear); }
ul.checklist li.is-done { color: var(--steel); }

/* ---------- Tables ---------- */
.tbl-wrap {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  margin: var(--space-4) 0;
}
table.data {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--fs-small);
}
table.data caption {
  text-align: left; padding: var(--space-3) var(--space-4);
  background: #FAFCFD; border-bottom: 1px solid var(--line);
  color: var(--steel); font-weight: 600;
  font-family: "Source Han Serif SC","Noto Serif SC","Songti SC","STSong","SimSun",serif;
  font-size: var(--fs-small);
}
table.data th, table.data td {
  text-align: left; padding: 9px 12px;
  border-bottom: 1px solid var(--line-soft);
  vertical-align: top;
  font-variant-numeric: tabular-nums;
}
table.data th {
  background: #F7F9FB;
  color: var(--steel);
  font-weight: 600;
  border-bottom: 1px solid var(--line);
  font-family: "Source Han Serif SC","Noto Serif SC","Songti SC","STSong","SimSun",serif;
}
table.data tbody tr:hover { background: #FAFCFD; }
table.data .row-head { color: var(--ink); font-weight: 600; }
table.data .col-num { text-align: right; white-space: nowrap; }
table.data .tag-anom { color: var(--amber); font-weight: 600; }
table.data .tag-ok   { color: var(--clear); font-weight: 600; }
table.data .tag-rust { color: var(--rust); font-weight: 600; }
table.data .wrap { white-space: normal; }
table.data .col-nowrap { white-space: nowrap; }
.tbl-scroll { overflow-x: auto; -webkit-overflow-scrolling: touch; }
.tbl-scroll > table.data { min-width: 640px; }

/* ---------- Anomaly cards (index) ---------- */
.anom-grid {
  display: grid; gap: var(--space-4);
  grid-template-columns: repeat(3, 1fr);
}
@media (max-width: 880px) { .anom-grid { grid-template-columns: 1fr; } }
.anom {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--space-5);
  position: relative; overflow: hidden;
}
.anom::before {
  content: ""; position: absolute; left: 0; top: 0; bottom: 0;
  width: 3px;
  background: var(--amber);
}
.anom--a { --anom-color: var(--amber); }
.anom--b { --anom-color: var(--rust); }
.anom--c { --anom-color: var(--steel); }
.anom__idx {
  font-family: "Source Han Serif SC","Noto Serif SC","Songti SC","STSong","SimSun",serif;
  font-size: 0.78rem; color: var(--anom-color);
  letter-spacing: 0.16em; font-weight: 600;
}
.anom__stage { font-size: var(--fs-small); color: var(--mist); margin-top: 2px; }
.anom__title {
  font-family: "Source Han Serif SC","Noto Serif SC","Songti SC","STSong","SimSun",serif;
  font-size: 1.08rem; font-weight: 600; color: var(--ink);
  margin: var(--space-3) 0 var(--space-2);
  line-height: 1.35;
}
.anom__desc { font-size: var(--fs-small); color: var(--steel); margin-bottom: var(--space-3); }
.anom__meta {
  border-top: 1px dashed var(--line);
  padding-top: var(--space-3);
  display: grid; grid-template-columns: auto 1fr; gap: 4px var(--space-3);
  font-size: var(--fs-micro);
}
.anom__meta dt { color: var(--mist); }
.anom__meta dd { margin: 0; color: var(--ink); }

/* ---------- Pipeline (process flow) ---------- */
.pipeline {
  display: flex; align-items: stretch; gap: 0;
  margin: var(--space-4) 0;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--card);
  overflow-x: auto;
}
.pipeline__step {
  flex: 1; min-width: 130px;
  padding: var(--space-3) var(--space-4);
  border-right: 1px solid var(--line-soft);
  position: relative;
}
.pipeline__step:last-child { border-right: none; }
.pipeline__step::after {
  content: "›"; position: absolute; right: -10px; top: 50%;
  transform: translateY(-50%); color: var(--mist); font-size: 1.2rem; z-index: 2;
  background: var(--card); padding: 0 2px;
}
.pipeline__step:last-child::after { content: none; }
.pipeline__step .step-no {
  font-family: "Source Han Serif SC","Noto Serif SC","Songti SC","STSong","SimSun",serif;
  font-size: 0.72rem; color: var(--amber); letter-spacing: 0.12em;
}
.pipeline__step .step-name {
  font-weight: 600; color: var(--ink); margin: 4px 0 2px;
  font-size: 0.96rem;
}
.pipeline__step .step-when { color: var(--mist); font-size: var(--fs-micro); }
.pipeline__step.is-anom { background: var(--amber-soft); }
.pipeline__step.is-anom .step-name { color: var(--warn); }

/* ---------- Chart canvases ---------- */
.chart {
  width: 100%; height: 320px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}
.chart--tall { height: 380px; }
.chart--short { height: 240px; }
.chart-title {
  font-size: var(--fs-small); color: var(--steel); font-weight: 600;
  font-family: "Source Han Serif SC","Noto Serif SC","Songti SC","STSong","SimSun",serif;
  margin: 0 0 var(--space-3);
}
.chart-foot {
  font-size: var(--fs-micro); color: var(--mist); margin-top: var(--space-2);
}
.chart-grid {
  display: grid; gap: var(--space-5);
  grid-template-columns: 1fr 1fr;
}
@media (max-width: 880px) { .chart-grid { grid-template-columns: 1fr; } }

/* ---------- Severity / rating chips ---------- */
.chip {
  display: inline-block; padding: 2px 8px;
  border-radius: 999px; font-size: var(--fs-micro);
  font-weight: 600; letter-spacing: 0.04em;
  border: 1px solid var(--line);
  background: var(--paper);
  color: var(--steel);
  font-variant-numeric: tabular-nums;
}
.chip--high   { background: #FBE8DC; color: var(--rust); border-color: #F1C9B4; }
.chip--mid    { background: #FCEED1; color: var(--warn); border-color: #EBD7A3; }
.chip--low    { background: #DCEBE3; color: var(--clear); border-color: #BBD6C8; }
.chip--anom   { background: var(--amber-soft); color: var(--warn); border-color: #E0C98F; }
.chip--ok     { background: #DCEBE3; color: var(--clear); border-color: #BBD6C8; }
.chip--info   { background: #E2EAF1; color: var(--steel); border-color: #B9C7D2; }

/* ---------- 5-Why chain ---------- */
.why-chain {
  display: flex; flex-direction: column; gap: 0;
  margin: var(--space-4) 0;
}
.why {
  display: grid; grid-template-columns: 110px 1fr;
  border: 1px solid var(--line);
  border-bottom: none;
  background: var(--card);
}
.why:first-child { border-radius: var(--radius) var(--radius) 0 0; }
.why:last-child  { border-radius: 0 0 var(--radius) var(--radius); border-bottom: 1px solid var(--line); }
.why__lvl {
  background: var(--paper);
  border-right: 1px solid var(--line);
  padding: var(--space-3) var(--space-4);
  display: flex; align-items: flex-start; justify-content: space-between;
  gap: var(--space-2);
  font-family: "Source Han Serif SC","Noto Serif SC","Songti SC","STSong","SimSun",serif;
}
.why__lvl .tag {
  display: inline-block; font-size: 0.7rem; letter-spacing: 0.14em;
  color: var(--amber); font-weight: 600;
}
.why__lvl .depth {
  font-size: 1.4rem; color: var(--ink); font-weight: 600; line-height: 1;
}
.why__body { padding: var(--space-3) var(--space-4); }
.why__q { color: var(--steel); font-size: var(--fs-small); margin-bottom: 4px; }
.why__a { color: var(--ink); }
.why__a ol { margin: 4px 0 0; padding-left: 1.2em; }
.why__a li { margin-bottom: 4px; }

/* ---------- Timeline ---------- */
.tl {
  position: relative; margin: var(--space-5) 0;
  padding-left: 0;
}
.tl::before {
  content: ""; position: absolute; left: 110px; top: 8px; bottom: 8px;
  width: 1px; background: var(--line);
}
.tl__row {
  display: grid; grid-template-columns: 110px 24px 1fr;
  align-items: flex-start; gap: var(--space-3);
  margin-bottom: var(--space-4);
  position: relative;
}
.tl__date {
  font-family: "Source Han Serif SC","Noto Serif SC","Songti SC","STSong","SimSun",serif;
  font-size: 0.92rem; color: var(--ink); font-weight: 600;
  font-variant-numeric: tabular-nums;
  text-align: right; padding-top: 2px;
}
.tl__dot {
  width: 12px; height: 12px; border-radius: 50%;
  background: var(--card); border: 2px solid var(--steel);
  margin: 6px auto 0; position: relative; z-index: 1;
}
.tl__dot.is-anom { background: var(--amber); border-color: var(--amber); }
.tl__dot.is-resolved { background: var(--clear); border-color: var(--clear); }
.tl__dot.is-rust { background: var(--rust); border-color: var(--rust); }
.tl__body { padding-top: 1px; }
.tl__stage {
  font-size: var(--fs-micro); color: var(--mist);
  letter-spacing: 0.08em; text-transform: uppercase;
  font-family: "Source Han Serif SC","Noto Serif SC","Songti SC","STSong","SimSun",serif;
}
.tl__title { color: var(--ink); font-weight: 600; margin: 2px 0 4px; }
.tl__desc { color: var(--steel); font-size: var(--fs-small); }

/* ---------- Figure / image card ---------- */
.figure {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--space-4);
  margin: var(--space-4) 0;
}
.figure img {
  width: 100%;
  height: auto;
  border-radius: 4px;
  background: linear-gradient(135deg, #F2F5F8 0%, #E6ECF1 100%);
  border: 1px solid var(--line-soft);
}
.figure__cap {
  font-size: var(--fs-small); color: var(--steel);
  margin-top: var(--space-3); padding-top: var(--space-3);
  border-top: 1px dashed var(--line);
}
.figure__cap strong { color: var(--ink); }

/* ---------- Footer ---------- */
.site-footer {
  border-top: 1px solid var(--line);
  background: var(--card);
  margin-top: var(--space-8);
  padding: var(--space-5) 0;
  font-size: var(--fs-small);
  color: var(--mist);
}
.site-footer__inner {
  max-width: var(--content-max);
  margin: 0 auto;
  padding: 0 var(--space-5);
  display: flex; align-items: center; justify-content: space-between;
  flex-wrap: wrap; gap: var(--space-3);
}

/* ---------- Print / accessibility niceties ---------- */
@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; }
}
:focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: 2px;
}