/* ============================================================
   DANIEL DEWAR — UPDATES
   "Full NASA-doc treatment"
   Reference: NASA technical reports & systems handbooks, 1962–75.
   ============================================================ */

:root{
  /* --- paper & ink --- */
  --paper:        #F2F1EB;
  --paper-2:      #E8E7E0;
  --ink:          #16160F;
  --ink-2:        #4A4A42;
  --ink-3:        #7C7C72;

  /* --- accents --- */
  --red:          #C4241B;   /* caution / revision marks */
  --blue:         #0B3D91;   /* NASA insignia blue */

  /* --- rules --- */
  --hair:         #C3C2B8;
  --rule-hair:    0.5px solid var(--hair);
  --rule-thin:    1px solid var(--ink);
  --rule-heavy:   2px solid var(--ink);

  /* --- type --- */
  --sans: "Helvetica Neue", Helvetica, "Inter", "Univers", Arial, sans-serif;
  --mono: "SF Mono", "Roboto Mono", "IBM Plex Mono", ui-monospace, Menlo, monospace;

  /* --- grid --- */
  --gut: 32px;
  --meta-col: 148px;
  --measure: 34em;
}

*{box-sizing:border-box;}

html{ -webkit-text-size-adjust:100%; }

body{
  margin:0;
  background:var(--paper);
  color:var(--ink);
  font-family:var(--sans);
  font-size:16px;
  line-height:1.62;
  letter-spacing:-0.003em;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}

/* faint engineering grid, like a reproduced blueprint sheet */
body::before{
  content:"";
  position:fixed; inset:0;
  pointer-events:none;
  background-image:
    linear-gradient(to right, rgba(22,22,15,.028) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(22,22,15,.028) 1px, transparent 1px);
  background-size:24px 24px;
  z-index:0;
}

.sheet{
  position:relative;
  z-index:1;
  max-width:1080px;
  margin:0 auto;
  padding:0 28px 120px;
}

/* ------------------------------------------------------------
   1.0  DOCUMENT HEADER BLOCK
   ------------------------------------------------------------ */

.doc-head{
  border-bottom:var(--rule-heavy);
  padding-top:36px;
}

.doc-head__top{
  display:flex;
  align-items:flex-start;
  justify-content:space-between;
  gap:24px;
  padding-bottom:14px;
}

.insignia{
  display:flex;
  align-items:center;
  gap:11px;
}

.insignia__mark{
  width:26px;height:26px;
  border:1.5px solid var(--ink);
  border-radius:50%;
  position:relative;
  flex:0 0 auto;
}
.insignia__mark::after{
  content:"";
  position:absolute;
  left:50%; top:50%;
  width:17px; height:1.5px;
  background:var(--red);
  transform:translate(-50%,-50%) rotate(-22deg);
}

.insignia__text{
  font-family:var(--mono);
  font-size:11px;
  letter-spacing:.16em;
  text-transform:uppercase;
  line-height:1.35;
}
.insignia__text b{ font-weight:700; display:block; }
.insignia__text span{ color:var(--ink-3); display:block; }

/* the control table — the single most "NASA" element */
.control{
  border-collapse:collapse;
  font-family:var(--mono);
  font-size:10px;
  letter-spacing:.09em;
  text-transform:uppercase;
}
.control td, .control th{
  border:var(--rule-hair);
  padding:3px 9px;
  text-align:left;
  white-space:nowrap;
}
.control th{
  color:var(--ink-3);
  font-weight:400;
  background:var(--paper-2);
}
.control td{ font-weight:600; }
.control .flag{ color:var(--red); }

/* ------------------------------------------------------------
   2.0  MASTHEAD
   ------------------------------------------------------------ */

.masthead{
  padding:30px 0 22px;
  border-bottom:var(--rule-thin);
  display:grid;
  grid-template-columns:var(--meta-col) 1fr;
  gap:var(--gut);
}

.masthead__label{
  font-family:var(--mono);
  font-size:10px;
  letter-spacing:.14em;
  text-transform:uppercase;
  color:var(--ink-3);
  padding-top:.55em;
}

.masthead h1{
  margin:0;
  font-size:clamp(26px,4.4vw,40px);
  font-weight:700;
  letter-spacing:-0.022em;
  line-height:1.06;
  text-transform:uppercase;
}
.masthead p{
  margin:12px 0 0;
  max-width:var(--measure);
  font-size:15px;
  color:var(--ink-2);
  line-height:1.6;
}

/* ------------------------------------------------------------
   3.0  BACK LINK RAIL (article view)
   ------------------------------------------------------------ */

nav.rail{
  display:flex;
  gap:6px 26px;
  flex-wrap:wrap;
  padding:11px 0;
  border-bottom:var(--rule-thin);
  font-family:var(--mono);
  font-size:10.5px;
  letter-spacing:.15em;
  text-transform:uppercase;
}
nav.rail a{
  color:var(--ink-2);
  text-decoration:none;
  padding-bottom:2px;
  border-bottom:1px solid transparent;
}
nav.rail a:hover{ color:var(--ink); border-bottom-color:var(--red); }

/* ------------------------------------------------------------
   4.0  SECTION HEADINGS
   ------------------------------------------------------------ */

.section-head{
  display:grid;
  grid-template-columns:var(--meta-col) 1fr;
  gap:var(--gut);
  align-items:baseline;
  padding:52px 0 10px;
  border-bottom:var(--rule-thin);
}
.section-head__no{
  font-family:var(--mono);
  font-size:10px;
  letter-spacing:.14em;
  color:var(--red);
  text-transform:uppercase;
}
.section-head h2{
  margin:0;
  font-size:13px;
  font-weight:700;
  letter-spacing:.16em;
  text-transform:uppercase;
}

/* ------------------------------------------------------------
   5.0  INDEX TABLE  (the "UPDATES" list, re-set as a manifest)
   ------------------------------------------------------------ */

.manifest{
  width:100%;
  border-collapse:collapse;
  margin-top:0;
}

.manifest thead th{
  font-family:var(--mono);
  font-size:9.5px;
  letter-spacing:.13em;
  text-transform:uppercase;
  color:var(--ink-3);
  font-weight:400;
  text-align:left;
  padding:10px 12px 8px 0;
  border-bottom:var(--rule-hair);
}

.manifest td{
  padding:0;
  border-bottom:var(--rule-hair);
  vertical-align:baseline;
}

.manifest tr:hover td{ background:rgba(196,36,27,.045); }

.manifest a{
  display:block;
  padding:13px 12px 13px 0;
  color:var(--ink);
  text-decoration:none;
}

.manifest .c-no{
  font-family:var(--mono);
  font-size:11px;
  color:var(--ink-3);
  letter-spacing:.05em;
  width:104px;
  white-space:nowrap;
}
.manifest .c-no a{ color:var(--ink-3); }
.manifest tr:hover .c-no a{ color:var(--red); }

.manifest .c-title a{
  font-size:17px;
  letter-spacing:-0.012em;
  font-weight:500;
}
.manifest tr:hover .c-title a{ text-decoration:underline; text-underline-offset:3px; }

.manifest .c-date{
  font-family:var(--mono);
  font-size:11px;
  color:var(--ink-3);
  letter-spacing:.05em;
  width:106px;
  white-space:nowrap;
}
.manifest .c-date a{ color:var(--ink-3); }

/* ------------------------------------------------------------
   6.0  ARTICLE VIEW
   ------------------------------------------------------------ */

.article{
  display:grid;
  grid-template-columns:var(--meta-col) 1fr;
  gap:var(--gut);
  padding-top:44px;
}

/* left margin column: sticky document metadata, as on a spec sheet */
.article__meta{
  font-family:var(--mono);
  font-size:10px;
  letter-spacing:.09em;
  text-transform:uppercase;
  color:var(--ink-3);
  position:sticky;
  top:26px;
  align-self:start;
}
.article__meta dl{ margin:0; }
.article__meta dt{
  padding-top:11px;
  margin-top:11px;
  border-top:var(--rule-hair);
  color:var(--ink-3);
}
.article__meta dt:first-child{ border-top:0; margin-top:0; padding-top:0; }
.article__meta dd{
  margin:3px 0 0;
  color:var(--ink);
  font-weight:600;
  letter-spacing:.06em;
}

.article__body{ max-width:var(--measure); min-width:0; }

.article__body h1{
  margin:0 0 18px;
  font-size:clamp(28px,5vw,42px);
  font-weight:700;
  line-height:1.05;
  letter-spacing:-0.026em;
  text-transform:uppercase;
}

.abstract{
  border-top:var(--rule-thin);
  border-bottom:var(--rule-hair);
  padding:16px 0;
  margin:0 0 34px;
  font-size:15px;
  line-height:1.55;
  color:var(--ink-2);
}
.abstract b{
  display:block;
  font-family:var(--mono);
  font-size:9.5px;
  letter-spacing:.15em;
  text-transform:uppercase;
  color:var(--ink-3);
  font-weight:400;
  margin-bottom:7px;
}

/* body copy — rendered from markdown */
.article__body p{
  margin:0 0 24px;
  font-size:17.5px;
  line-height:1.58;
  letter-spacing:-0.008em;
}

.article__body ul,
.article__body ol{
  margin:0 0 24px;
  padding-left:1.4em;
  font-size:17.5px;
  line-height:1.58;
  letter-spacing:-0.008em;
}
.article__body li{ margin-bottom:8px; }
.article__body li p{ margin-bottom:8px; }

.article__body a{
  color:var(--ink);
  text-decoration:underline;
  text-underline-offset:3px;
  text-decoration-thickness:1px;
}
.article__body a:hover{ color:var(--red); }

.article__body h2,
.article__body h3{
  margin:44px 0 18px;
  font-size:12px;
  font-weight:700;
  letter-spacing:.17em;
  text-transform:uppercase;
  padding-bottom:7px;
  border-bottom:var(--rule-thin);
}
.article__body h4,
.article__body h5,
.article__body h6{
  margin:32px 0 14px;
  font-size:11px;
  font-weight:700;
  letter-spacing:.15em;
  text-transform:uppercase;
  color:var(--ink-2);
}

.article__body blockquote{
  margin:32px 0;
  padding:18px 20px;
  border:var(--rule-thin);
  border-left:3px solid var(--red);
  background:var(--paper-2);
  font-size:16px;
  line-height:1.55;
}
.article__body blockquote p{ font-size:16px; margin:0; }
.article__body blockquote p + p{ margin-top:16px; }

.article__body img{
  max-width:100%;
  height:auto;
  display:block;
  margin:32px 0;
  border:var(--rule-hair);
}

.article__body hr{
  border:0;
  border-top:var(--rule-hair);
  margin:44px 0;
}

.article__body table{
  width:100%;
  border-collapse:collapse;
  margin:32px 0;
  font-size:14px;
}
.article__body table th{
  font-family:var(--mono);
  font-size:9.5px;
  letter-spacing:.13em;
  text-transform:uppercase;
  color:var(--ink-3);
  font-weight:400;
  text-align:left;
  padding:8px 12px 6px 0;
  border-bottom:var(--rule-hair);
}
.article__body table td{
  padding:8px 12px 8px 0;
  border-bottom:var(--rule-hair);
}

.article__body pre{
  background:var(--paper-2);
  border:var(--rule-hair);
  padding:16px;
  margin:32px 0;
  overflow-x:auto;
  font-family:var(--mono);
  font-size:13px;
  line-height:1.55;
}
.article__body pre code{
  display:block;
  background:transparent;
  padding:0;
  white-space:pre;
  color:var(--ink);
}
.article__body code{
  background:var(--paper-2);
  border:var(--rule-hair);
  padding:.15em .4em;
  font-family:var(--mono);
  font-size:85%;
  color:var(--ink);
}

/* ------------------------------------------------------------
   7.0  FOOTER / SIGNATURE BLOCK
   ------------------------------------------------------------ */

footer.doc-foot{
  margin-top:76px;
  border-top:var(--rule-heavy);
  padding-top:14px;
  display:flex;
  justify-content:space-between;
  gap:20px;
  flex-wrap:wrap;
  font-family:var(--mono);
  font-size:9.5px;
  letter-spacing:.13em;
  text-transform:uppercase;
  color:var(--ink-3);
}
footer.doc-foot a{ color:var(--ink-2); text-decoration:none; }
footer.doc-foot a:hover{ color:var(--red); }

/* ------------------------------------------------------------
   9.0  RESPONSIVE — collapse the margin column
   ------------------------------------------------------------ */

@media (max-width:760px){
  :root{ --gut:0px; }
  .sheet{ padding-left:20px; padding-right:20px; overflow-x:hidden; }

  .doc-head__top{ flex-direction:column; gap:16px; }
  .control{ font-size:8.5px; }
  .control td, .control th{ padding:3px 6px; }
  .control .opt{ display:none; }

  .masthead, .section-head, .article{ grid-template-columns:1fr; }
  .masthead__label, .section-head__no{ margin-bottom:8px; padding-top:0; }
  .masthead h1, .article__body h1{ overflow-wrap:break-word; hyphens:auto; }

  /* metadata becomes a two-column spec block, not a single wide row */
  .article__meta{
    position:static;
    border-bottom:var(--rule-hair);
    padding-bottom:16px; margin-bottom:28px;
  }
  .article__meta dl{ display:block; column-count:2; column-gap:22px; }
  .article__meta dt{
    border-top:0; padding-top:0;
    font-size:9px;
    break-inside:avoid; margin-top:12px;
  }
  .article__meta dt:first-child{ margin-top:0; }
  .article__meta dd{ margin:2px 0 0; }

  .manifest .c-no, .manifest thead .c-no{ display:none; }
  .manifest .c-date{ width:74px; font-size:9.5px; }
  .manifest .c-title a{ font-size:15.5px; }
}

@media (prefers-color-scheme:dark){
  :root{
    --paper:#111310; --paper-2:#1B1E1A; --ink:#EDEDE6;
    --ink-2:#B0B0A6; --ink-3:#7E7E74; --hair:#33362F;
    --red:#F1524A; --rule-thin:1px solid #EDEDE6; --rule-heavy:2px solid #EDEDE6;
  }
  body::before{ background-image:
    linear-gradient(to right, rgba(237,237,230,.028) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(237,237,230,.028) 1px, transparent 1px); }
  .manifest tr:hover td{ background:rgba(241,82,74,.07); }
}