/* ============================================================
   Spacewar! · front door
   Aesthetic: DEC PDP-1 Type 30 CRT (P7 phosphor, blue-white),
   vector graphics, teletype/Macro listing. Monochrome phosphor
   on black, with bloom, scanlines and a faint flicker.
   ============================================================ */

:root {
  --bg:        #04060b;          /* CRT black */
  --bg-2:      #070b14;
  --panel:     rgba(120, 200, 255, 0.035);
  --line:      rgba(120, 200, 255, 0.22);
  --line-soft: rgba(120, 200, 255, 0.12);
  --phosphor:  #bfe4ff;          /* body text (Type 30 blue-white) */
  --phosphor-dim: #7fa6c4;
  --bright:    #eaf6ff;          /* headings */
  --beam:      #6cf2ff;          /* vector lines / links (bright cyan) */
  --beam-warm: #ffce7a;          /* sparing amber accent: octal, cursor */
  --glow:      0 0 6px rgba(108, 242, 255, 0.55), 0 0 14px rgba(108, 242, 255, 0.28);
  --glow-soft: 0 0 5px rgba(191, 228, 255, 0.45);
  --mono: ui-monospace, "SF Mono", "JetBrains Mono", "Cascadia Code", Menlo, Consolas, monospace;
  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, serif;
  --wrap: 920px;
  /* DEC PDP-1 hardware palette (from the Type 30 console): robin's-egg blue panels, cream cabinet */
  --dec-blue: #5f93a8;
  --dec-blue-bright: #8fc3d6;
  --dec-cream: #e7e1d0;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background:
    radial-gradient(ellipse 120% 80% at 50% -10%, var(--bg-2) 0%, var(--bg) 60%) fixed;
  color: var(--phosphor);
  font-family: var(--serif);
  font-size: 18px;
  line-height: 1.65;
  letter-spacing: 0.1px;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

/* CRT overlays: scanlines + vignette + faint flicker. */
body::before,
body::after {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 9000;
}
body::before { /* scanlines */
  background: repeating-linear-gradient(
    to bottom,
    rgba(0, 0, 0, 0) 0px,
    rgba(0, 0, 0, 0) 2px,
    rgba(0, 0, 0, 0.22) 3px,
    rgba(0, 0, 0, 0.22) 4px);
  mix-blend-mode: multiply;
  opacity: 0.55;
}
body::after { /* vignette + flicker */
  background: radial-gradient(ellipse 90% 75% at 50% 45%, transparent 55%, rgba(0,0,0,0.55) 100%);
  animation: flicker 5.5s infinite steps(60);
}
@keyframes flicker {
  0%, 100% { opacity: 1; }
  47% { opacity: 0.97; }
  48% { opacity: 0.92; }
  49% { opacity: 0.99; }
  92% { opacity: 0.96; }
}
@media (prefers-reduced-motion: reduce) {
  body::after { animation: none; }
}

.wrap { width: min(var(--wrap), 92vw); margin: 0 auto; }

/* offset anchor jumps so the sticky header doesn't cover the target heading */
section[id], [id]:target { scroll-margin-top: 92px; }

/* ---------- links ---------- */
a { color: var(--beam); text-decoration: none; }
a:hover { color: var(--bright); text-shadow: var(--glow); }
.content a { border-bottom: 1px solid var(--line); }
.content a:hover { border-bottom-color: var(--beam); }

/* ---------- header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 8000;
  backdrop-filter: blur(3px);
  background: linear-gradient(to bottom, rgba(4,6,11,0.92), rgba(4,6,11,0.6));
  border-bottom: 1px solid var(--line-soft);
}
.site-header .wrap {
  display: flex; align-items: center; justify-content: space-between;
  padding: 12px 0; gap: 1rem; position: relative;
}
.brand { display: flex; align-items: center; gap: 0.7rem; border: 0 !important; }
.brand svg { width: 30px; height: 30px; filter: drop-shadow(var(--glow)); }
.brand-block { display: flex; flex-direction: column; line-height: 1.1; }
.brand-text {
  font-family: var(--mono); font-weight: 700; letter-spacing: 2px;
  color: var(--bright); text-shadow: var(--glow-soft); font-size: 1rem;
}
.brand-tagline { font-family: var(--mono); font-size: 0.62rem; letter-spacing: 1px; color: var(--phosphor-dim); text-transform: uppercase; }
.nav-toggle {
  display: inline-flex; align-items: center; gap: 0.5rem;
  background: none; border: 1px solid var(--line); color: var(--beam);
  font-family: var(--mono); font-size: 0.7rem; letter-spacing: 1.5px; text-transform: uppercase;
  padding: 7px 13px; border-radius: 3px; cursor: pointer;
}
.nav-toggle:hover { border-color: var(--beam); color: var(--bright); text-shadow: var(--glow); }
.nav-toggle .bars { font-size: 0.95rem; line-height: 1; }
/* ---------- nav: mobile-first hamburger panel with accordion groups ---------- */
.site-nav {
  position: absolute; top: calc(100% + 7px); right: 0;
  display: none; flex-direction: column;
  min-width: 220px; max-width: min(300px, 90vw); padding: 0.4rem 0;
  background: rgba(5,9,15,0.98); border: 1px solid var(--line); border-radius: 4px;
  box-shadow: 0 12px 32px rgba(0,0,0,0.6);
  font-family: var(--mono); font-size: 0.74rem; letter-spacing: 0.8px; text-transform: uppercase;
}
.site-nav.open { display: flex; }
.nav-group { position: static; display: flex; flex-direction: column; }
.nav-top {
  background: none; border: 0; cursor: pointer; text-align: left;
  font-family: var(--mono); font-size: 0.74rem; letter-spacing: 0.8px; text-transform: uppercase;
  color: var(--phosphor-dim); padding: 0.6rem 1.2rem; text-decoration: none;
  display: flex; align-items: center; justify-content: space-between; gap: 0.4rem; width: 100%;
}
.nav-top:hover, .nav-top:focus-visible { color: var(--beam); text-shadow: var(--glow); background: rgba(108,242,255,0.06); outline: none; }
.nav-top .caret { font-size: 0.7em; opacity: 0.7; transition: transform 0.15s ease; }
.nav-top[aria-expanded="true"] .caret { transform: rotate(180deg); }
.nav-menu { display: none; flex-direction: column; background: rgba(108,242,255,0.035); }
.nav-menu.open { display: flex; }
.nav-menu a { color: var(--phosphor-dim); border: 0; padding: 0.5rem 1.2rem 0.5rem 2rem; text-decoration: none; }
.nav-menu a:hover { color: var(--beam); text-shadow: var(--glow); background: rgba(108,242,255,0.06); }

/* ---------- nav: desktop horizontal bar with hover/click dropdowns ---------- */
@media (min-width: 900px) {
  .nav-toggle { display: none; }
  .site-nav {
    position: static; display: flex; flex-direction: row; align-items: center; gap: 0.1rem;
    min-width: 0; max-width: none; padding: 0; background: none; border: 0; box-shadow: none;
  }
  .nav-group { position: relative; display: inline-block; }
  .nav-top { width: auto; justify-content: center; padding: 0.55rem 0.7rem; }
  .nav-menu {
    position: absolute; top: 100%; left: 0; margin-top: 0; min-width: 180px;
    background: rgba(5,9,15,0.98); border: 1px solid var(--line); border-radius: 4px;
    box-shadow: 0 12px 32px rgba(0,0,0,0.6); padding: 0.3rem 0; z-index: 9000;
  }
  /* Click to open (handled in nav.js); no hover-open, so the menu does not vanish
     when the cursor crosses to it. focus-within keeps it open for keyboard users. */
  .nav-group:focus-within .nav-menu, .nav-menu.open { display: flex; }
  .nav-menu a { padding: 0.5rem 1.1rem; white-space: nowrap; }
  .site-nav > .nav-group:last-of-type .nav-menu { left: auto; right: 0; }
}

/* ---------- hero ---------- */
.hero { position: relative; min-height: 78vh; display: flex; align-items: center; overflow: hidden; border-bottom: 1px solid var(--line-soft); }
#starfield { position: absolute; inset: 0; width: 100%; height: 100%; z-index: 0; }
.hero-inner { position: relative; z-index: 2; padding: 8vh 0; }
.boot { font-family: var(--mono); font-size: 0.78rem; letter-spacing: 3px; color: var(--phosphor-dim); text-transform: uppercase; margin-bottom: 1.4rem; }
.cursor { display: inline-block; width: 0.6em; height: 1.05em; vertical-align: -0.15em; background: var(--beam-warm); box-shadow: 0 0 8px var(--beam-warm); animation: blink 1.06s steps(1) infinite; margin-left: 2px; }
@keyframes blink { 50% { opacity: 0; } }
@media (prefers-reduced-motion: reduce) { .cursor { animation: none; } }

.hero h1 {
  font-family: var(--mono); font-weight: 800;
  font-size: clamp(3rem, 11vw, 7.5rem); line-height: 0.92;
  margin: 0; letter-spacing: -2px; color: var(--bright);
  text-shadow: 0 0 12px rgba(108,242,255,0.6), 0 0 38px rgba(108,242,255,0.35), 0 0 70px rgba(108,242,255,0.18);
}
.hero h1 .bang { color: var(--beam); }
.hero .sub { font-family: var(--mono); font-size: clamp(0.85rem, 2.2vw, 1.05rem); letter-spacing: 2px; color: var(--phosphor); margin-top: 0.6rem; text-transform: uppercase; }
.hero .tagline { max-width: 40ch; margin-top: 1.6rem; font-size: 1.15rem; color: var(--phosphor); }
.hero-actions { margin-top: 2.2rem; display: flex; gap: 1rem; flex-wrap: wrap; }

/* ---------- buttons ---------- */
.btn {
  font-family: var(--mono); font-size: 0.82rem; letter-spacing: 1.5px; text-transform: uppercase;
  padding: 0.8rem 1.5rem; border: 1px solid var(--beam); color: var(--beam);
  background: rgba(108,242,255,0.05); border-radius: 2px; transition: all 0.18s ease;
}
.btn:hover { background: var(--beam); color: var(--bg); box-shadow: var(--glow); border-bottom: 1px solid var(--beam); }
.btn.ghost { border-color: var(--line); color: var(--phosphor-dim); background: transparent; }
.btn.ghost:hover { border-color: var(--phosphor); color: var(--bright); background: rgba(191,228,255,0.05); box-shadow: none; }

/* ---------- content ---------- */
.content { padding: 5rem 0; }
section.block { margin: 0 auto 5rem; }
section.block:last-child { margin-bottom: 0; }

.kicker { font-family: var(--mono); font-size: 0.72rem; letter-spacing: 3px; text-transform: uppercase; color: var(--beam); margin-bottom: 0.9rem; display: block; }

h2 { font-family: var(--mono); font-weight: 700; font-size: clamp(1.5rem, 4vw, 2.1rem); color: var(--bright); letter-spacing: -0.5px; margin: 0 0 1.2rem; text-shadow: var(--glow-soft); }
h3 { font-family: var(--mono); font-weight: 700; font-size: 1.05rem; color: var(--bright); letter-spacing: 0.5px; margin: 0 0 0.5rem; }
.lede p { font-size: 1.28rem; line-height: 1.6; color: var(--phosphor); max-width: 60ch; }
.content p { max-width: 68ch; }
.content p + p { margin-top: 1.1rem; }

/* phosphor rule with octal address motif */
.rule { display: flex; align-items: center; gap: 1rem; margin: 3.5rem 0; color: var(--phosphor-dim); font-family: var(--mono); font-size: 0.7rem; letter-spacing: 2px; }
.rule::before, .rule::after { content: ""; height: 1px; flex: 1; background: linear-gradient(to right, transparent, var(--line), transparent); }

/* card grid */
.grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); gap: 1.1rem; margin-top: 1.5rem; }
.card {
  border: 1px solid var(--line-soft); background: var(--panel);
  padding: 1.4rem; border-radius: 3px; transition: border-color 0.2s ease, box-shadow 0.2s ease, transform 0.2s ease;
  position: relative;
}
.card:hover { border-color: var(--beam); box-shadow: inset 0 0 30px rgba(108,242,255,0.06), var(--glow); transform: translateY(-2px); }
.card .obj { font-family: var(--mono); font-size: 0.68rem; letter-spacing: 1.5px; text-transform: uppercase; color: var(--phosphor-dim); margin: 0 0 0.6rem; }
.card p { font-size: 0.95rem; color: var(--phosphor); margin: 0; max-width: none; }
.card h3 a { border: 0; }

/* code listing motif */
.listing {
  font-family: var(--mono); font-size: 0.82rem; line-height: 1.55;
  background: rgba(0,0,0,0.5); border: 1px solid var(--line-soft); border-left: 2px solid var(--beam);
  padding: 1.2rem 1.3rem; border-radius: 3px; overflow-x: auto; color: var(--phosphor);
  text-shadow: 0 0 4px rgba(191,228,255,0.3); margin-top: 1.5rem;
}
.listing .addr { color: var(--beam-warm); opacity: 0.8; }
.listing .com { color: var(--phosphor-dim); }
.listing .kw { color: var(--beam); }

/* method list */
.method { list-style: none; padding: 0; margin: 1.5rem 0 0; display: grid; gap: 1rem; }
.method li { padding-left: 2.4rem; position: relative; }
.method li::before { content: attr(data-n); position: absolute; left: 0; top: 0; font-family: var(--mono); font-size: 0.8rem; color: var(--beam-warm); border: 1px solid var(--line); border-radius: 50%; width: 1.7rem; height: 1.7rem; display: flex; align-items: center; justify-content: center; }
.method b { color: var(--bright); font-family: var(--mono); font-weight: 700; font-size: 0.95rem; }

/* play CTA */
.cta { border: 1px solid var(--line); background: linear-gradient(135deg, rgba(108,242,255,0.06), rgba(108,242,255,0.01)); padding: 2.6rem; border-radius: 4px; text-align: center; }
.cta h2 { margin-bottom: 0.6rem; }
.cta p { margin: 0 auto 1.6rem; }

/* further reading */
.reading ul { list-style: none; padding: 0; margin: 1rem 0 2rem; }
.reading li { padding: 0.55rem 0; border-bottom: 1px solid var(--line-soft); }
.reading li::before { content: "› "; color: var(--beam); font-family: var(--mono); }
.reading h3 { margin-top: 2rem; color: var(--beam); }

/* ---------- footer ---------- */
.site-footer { border-top: 1px solid var(--line-soft); padding: 1.4rem 0; margin-top: 2.5rem; font-family: var(--mono); font-size: 0.78rem; color: var(--phosphor-dim); letter-spacing: 0.5px; }
.site-footer .wrap { display: flex; flex-direction: column; gap: 0.35rem; }
.site-footer a { color: var(--phosphor-dim); border: 0; }
.site-footer a:hover { color: var(--beam); }

/* ---------- play page ---------- */
.play-stage { display: flex; flex-direction: column; align-items: center; padding: 3rem 0 4rem; }
.play-frame { position: relative; width: min(620px, 92vw); aspect-ratio: 1 / 1; border: 1px solid var(--line); border-radius: 50% / 6%; padding: 18px; background: radial-gradient(ellipse at center, rgba(108,242,255,0.04), transparent 70%); box-shadow: inset 0 0 60px rgba(108,242,255,0.06), 0 0 40px rgba(0,0,0,0.6); }
canvas#swcanvas { display: block; width: 100%; height: 100%; background: #000; border-radius: 4px; image-rendering: pixelated; }
.controls { font-family: var(--mono); font-size: 0.8rem; color: var(--phosphor-dim); letter-spacing: 1px; margin-top: 1.8rem; text-align: center; line-height: 2; }
.controls kbd { font-family: var(--mono); color: var(--beam); border: 1px solid var(--line); border-radius: 3px; padding: 1px 7px; margin: 0 1px; text-shadow: var(--glow); }

/* inline link rows (CCS / further reading) */
.links { list-style: none; padding: 0; margin: 1.4rem 0 0; display: grid; gap: 0.65rem; }
.links li { padding-left: 1.3rem; position: relative; }
.links li::before { content: "→"; position: absolute; left: 0; color: var(--beam); font-family: var(--mono); }
.links .meta { color: var(--phosphor-dim); font-size: 0.9rem; }

/* callout (ELIZA companion) */
.callout { border: 1px solid var(--line-soft); border-left: 3px solid var(--dec-blue); background: linear-gradient(110deg, rgba(95,147,168,0.08), rgba(95,147,168,0.01)); padding: 1.8rem 2rem; border-radius: 3px; }
.callout .kicker { color: var(--dec-blue-bright); }
.callout p { margin: 0; }
.callout p + p { margin-top: 0.8rem; }

/* stat strip · the machine in numbers */
.stat-strip { display: flex; flex-wrap: wrap; gap: 0; margin-top: 1.6rem; border: 1px solid var(--line-soft); border-radius: 3px; overflow: hidden; }
.stat { flex: 1 1 140px; padding: 1.1rem 1.2rem; border-right: 1px solid var(--line-soft); background: rgba(95,147,168,0.03); }
.stat:last-child { border-right: 0; }
.stat .n { font-family: var(--mono); font-size: 1.5rem; color: var(--dec-blue-bright); text-shadow: 0 0 8px rgba(143,195,214,0.4); line-height: 1.1; }
.stat .l { font-family: var(--mono); font-size: 0.64rem; letter-spacing: 1.5px; text-transform: uppercase; color: var(--phosphor-dim); margin-top: 0.4rem; }

/* fact cards: labelled */
.fact .obj { color: var(--dec-blue-bright); }
.fact b { color: var(--bright); }

/* hardware illustration */
.hardware { display: grid; grid-template-columns: 1.1fr 1fr; gap: 2.5rem; align-items: center; margin-top: 1.8rem; }
.hardware svg { width: 100%; height: auto; }
@media (max-width: 700px) { .hardware { grid-template-columns: 1fr; } }

/* contacts */
.contacts { display: grid; grid-template-columns: 1fr 1fr; gap: 1.1rem; margin-top: 1.5rem; }
.contact { border: 1px solid var(--line-soft); padding: 1.3rem 1.4rem; border-radius: 3px; background: var(--panel); }
.contact .role { font-family: var(--mono); font-size: 0.64rem; letter-spacing: 1.5px; text-transform: uppercase; color: var(--phosphor-dim); }
.contact .name { font-family: var(--mono); color: var(--bright); font-size: 1.02rem; margin: 0.3rem 0; }
.contact .aff { font-size: 0.9rem; color: var(--phosphor); }
.contact a { font-family: var(--mono); font-size: 0.82rem; }
@media (max-width: 620px) { .contacts { grid-template-columns: 1fr; } }

/* version status pills */
.status, .vtable .st {
  display: inline-block; font-family: var(--mono); font-size: 0.56rem; font-weight: 700;
  letter-spacing: 1px; text-transform: uppercase; line-height: 1.4; white-space: nowrap;
  padding: 1px 7px; border-radius: 999px; border: 1px solid;
}
.status { margin-left: 0.55rem; vertical-align: middle; }
.status.recovered, .vtable .st.recovered { color: #8df0b4; background: rgba(111,220,154,0.14); border-color: rgba(111,220,154,0.55); }
.status.partial,   .vtable .st.partial   { color: #ffd58a; background: rgba(255,206,122,0.14); border-color: rgba(255,206,122,0.55); }
.status.lost,      .vtable .st.lost      { color: #f0a4a4; background: rgba(224,138,138,0.14); border-color: rgba(224,138,138,0.55); }

/* version summary table */
.vtable-wrap { overflow-x: auto; margin-top: 1.6rem; border: 1px solid var(--line-soft); border-radius: 3px; }
.vtable { width: 100%; border-collapse: collapse; font-size: 0.76rem; min-width: 600px; }
.vtable th, .vtable td { text-align: left; padding: 0.5rem 0.8rem; border: 1px solid var(--line-soft); vertical-align: top; }
.vtable thead th { font-family: var(--mono); font-size: 0.6rem; letter-spacing: 1.5px; text-transform: uppercase; color: var(--beam); border-color: var(--line); background: rgba(108,242,255,0.04); }
.vtable tbody tr:nth-child(odd) td { background: rgba(120,200,255,0.02); }
.vtable td:first-child { font-family: var(--mono); color: var(--bright); white-space: nowrap; }
.vtable .st { font-family: var(--mono); font-size: 0.58rem; letter-spacing: 1px; text-transform: uppercase; white-space: nowrap; }
.vtable .st.recovered { color: #6fdc9a; }
.vtable .st.partial { color: var(--beam-warm); }
.vtable .st.lost { color: #e08a8a; }

/* bibliography */
.bib .ref { font-family: var(--serif); font-size: 0.95rem; line-height: 1.5; padding-left: 1.7rem; text-indent: -1.7rem; margin: 0 0 0.75rem; max-width: 74ch; color: var(--phosphor); }
.bib .ref a { border-bottom: 1px solid var(--line-soft); word-break: break-word; }
.bib .ref a:hover { border-bottom-color: var(--beam); }

/* tiny footer / credit type */
.micro { font-size: 0.66rem; color: var(--phosphor-dim); letter-spacing: 0.4px; line-height: 1.5; }
.micro a { color: var(--phosphor-dim); border: 0; }
.micro a:hover { color: var(--beam); }

@media (max-width: 620px) {
  .brand-tagline { display: none; }
  .content { padding: 3rem 0; }
}