/* Shared slide engine styles — graph-paper "blueprint notebook" look */
@import url('https://fonts.googleapis.com/css2?family=Atkinson+Hyperlegible:ital,wght@0,400;0,700;1,400&family=Bricolage+Grotesque:opsz,wght@12..96,500;12..96,700;12..96,800&family=JetBrains+Mono:wght@400;600&display=swap');

:root {
  --paper: #f4f6f9;
  --grid: #dce3ee;
  --ink: #1b2230;
  --muted: #5b6577;
  --blue: #2552c9;
  --green: #13795b;
  --red: #c8372d;
  --sticky: #ffe76a;
  --display: 'Bricolage Grotesque', system-ui, sans-serif;
  --body: 'Atkinson Hyperlegible', system-ui, sans-serif;
  --mono: 'JetBrains Mono', ui-monospace, monospace;
}
* { box-sizing: border-box; }
html, body { margin: 0; height: 100%; background: #c9d1dd; overflow: hidden; font-family: var(--body); color: var(--ink); }

/* 1600×900 stage scaled to the window by deck.js */
.stage { position: absolute; top: 50%; left: 50%; width: 1600px; height: 900px; transform-origin: center; }
.slide {
  position: absolute; inset: 0; display: none; flex-direction: column; padding: 72px 96px 64px;
  background-color: var(--paper);
  background-image:
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 40px 40px; background-position: -1px -1px;
  box-shadow: 0 10px 40px rgb(27 34 48 / 0.25);
}
.slide.active { display: flex; }
.slide > .notes { display: none; }

/* Segment strip: where we are in the lecture */
.seg { position: absolute; top: 24px; left: 96px; font: 600 18px var(--mono); color: var(--muted); }
.seg b { color: var(--blue); font-weight: 600; }
.pageno { position: absolute; bottom: 22px; right: 32px; font: 16px var(--mono); color: var(--muted); }
.progress { position: absolute; left: 0; bottom: 0; height: 6px; background: var(--blue); transition: width .25s; }

h1, h2, h3 { font-family: var(--display); margin: 0; letter-spacing: -0.02em; line-height: 1.05; }
h1 { font-size: 112px; font-weight: 800; }
h2 { font-size: 64px; font-weight: 700; margin-bottom: 36px; }
h3 { font-size: 36px; font-weight: 700; margin-bottom: 12px; }
p, li { font-size: 34px; line-height: 1.4; }
p { margin: 0 0 20px; max-width: 30em; }
ul, ol { margin: 0; padding-left: 1.1em; }
li { margin-bottom: 14px; max-width: 30em; }
li::marker { color: var(--blue); }
code { font-family: var(--mono); font-size: .85em; background: #fff; border: 1px solid var(--grid); padding: 0 .25em; border-radius: 4px; }
pre { font: 24px/1.45 var(--mono); background: var(--ink); color: #e9edf5; padding: 28px 32px; border-radius: 10px; margin: 0; overflow: hidden; white-space: pre-wrap; }
pre .c { color: #8fa1bd; }
.muted { color: var(--muted); }
.small p, .small li { font-size: 28px; }

/* Title slide */
.slide.title { justify-content: center; }
.slide.title h1 { max-width: 13em; }
.slide.title .kicker { font: 600 26px var(--mono); color: var(--blue); margin-bottom: 28px; }
.slide.title .sub { font-size: 36px; color: var(--muted); margin-top: 28px; }

/* Statement slide: one big idea */
.slide.statement { justify-content: center; }
.slide.statement h2 { font-size: 88px; max-width: 15em; margin: 0; }
.slide.statement p { margin-top: 32px; font-size: 38px; color: var(--muted); }

/* Diagram slide: tldraw export fills the stage */
.slide.diagram { padding: 56px 64px 48px; align-items: center; justify-content: center; }
.slide.diagram img { max-width: 100%; max-height: 100%; object-fit: contain; border-radius: 8px; background: #f9fafb; box-shadow: 0 2px 0 var(--grid); cursor: zoom-in; }
.slide.diagram .src { position: absolute; bottom: 20px; left: 64px; font: 15px var(--mono); color: var(--muted); }

/* "Ask the class" — a tldraw-style sticky note */
.slide.ask { justify-content: center; align-items: center; }
.sticky {
  background: var(--sticky); width: 1080px; padding: 64px 72px; transform: rotate(-1.5deg);
  box-shadow: 0 18px 30px -12px rgb(27 34 48 / 0.35); font-family: var(--display);
}
.sticky .who { font: 600 24px var(--mono); margin-bottom: 18px; }
.sticky .q { font-size: 60px; font-weight: 700; line-height: 1.12; }
.sticky .how { font: 28px var(--body); margin-top: 28px; }

/* Activity slide */
.slide.activity { border-top: 18px solid var(--green); }
.slide.activity h2 { color: var(--green); padding-right: 330px; }
.steps { counter-reset: s; list-style: none; padding: 0; }
.steps li { counter-increment: s; position: relative; padding-left: 64px; }
.steps li::before { content: counter(s); position: absolute; left: 0; top: 2px; width: 44px; height: 44px; border-radius: 50%; background: var(--green); color: #fff; font: 700 26px/44px var(--display); text-align: center; }
.countdown {
  position: absolute; right: 96px; top: 72px; font: 700 96px var(--mono); color: var(--green);
  background: #fff; border: 4px solid var(--green); border-radius: 16px; padding: 4px 28px; cursor: pointer; user-select: none;
}
.countdown.done { color: #fff; background: var(--red); border-color: var(--red); }
.countdown::after { content: 'click to start · R to reset'; display: block; font: 16px var(--mono); color: var(--muted); text-align: center; }
.countdown.running::after { content: 'click to pause'; }
.countdown.done::after { content: "time's up"; color: #fff; }

/* Layout helpers */
.cols { display: grid; grid-template-columns: 1fr 1fr; gap: 56px; align-items: start; }
.cols.wide-left { grid-template-columns: 1.35fr 1fr; }
.card { background: #fff; border: 2px solid var(--ink); border-radius: 10px; padding: 28px 32px; }
.card.blue { border-color: var(--blue); } .card.green { border-color: var(--green); } .card.red { border-color: var(--red); }
.card h3 { font-size: 32px; }
.card p, .card li { font-size: 27px; }
.tag { display: inline-block; font: 600 20px var(--mono); padding: 4px 12px; border-radius: 6px; background: var(--ink); color: #fff; margin-right: 8px; }
.tag.blue { background: var(--blue); } .tag.green { background: var(--green); } .tag.red { background: var(--red); }
.bottomline { margin-top: auto; font: 700 34px var(--display); border-left: 8px solid var(--blue); padding-left: 24px; }
.grid4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
.grid3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 28px; }
.grid2x4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.grid2x4 .card { padding: 22px 24px; }
.grid2x4 .card p { font-size: 25px; margin: 0; }
.grid2x4 .card b { display: block; font: 700 22px var(--mono); color: var(--blue); margin-bottom: 8px; }

/* Click-to-zoom overlay for diagrams */
.zoom { position: fixed; inset: 0; background: rgb(27 34 48 / .92); display: none; align-items: center; justify-content: center; z-index: 50; cursor: zoom-out; }
.zoom.on { display: flex; }
.zoom img { max-width: 98vw; max-height: 98vh; }

/* Overview grid (O key) */
.overview { position: fixed; inset: 0; background: #e8edf4; overflow: auto; display: none; z-index: 60; padding: 32px; }
.overview.on { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 14px; align-content: start; }
.overview button { text-align: left; font: 16px var(--body); background: #fff; border: 2px solid transparent; border-radius: 8px; padding: 14px; cursor: pointer; }
.overview button.cur { border-color: var(--blue); }
.overview button span { display: block; font: 12px var(--mono); color: var(--muted); }
.help { position: fixed; bottom: 10px; left: 12px; font: 12px var(--mono); color: #5b6577; opacity: .7; z-index: 40; }

:focus-visible { outline: 3px solid var(--blue); outline-offset: 3px; }
@media (prefers-reduced-motion: reduce) { * { transition: none !important; } }

/* Presenter window */
body.presenter { overflow: auto; background: #10151f; color: #e9edf5; font-family: var(--body); }
.pv { display: grid; grid-template-columns: 1fr 380px; gap: 24px; padding: 24px; min-height: 100vh; }
.pv .now { font: 700 30px var(--display); margin-bottom: 8px; }
.pv .segname { font: 600 16px var(--mono); color: #8fa1bd; }
.pv .notesbox { font-size: 23px; line-height: 1.5; background: #1a2130; border-radius: 10px; padding: 20px 26px; margin-top: 14px; }
.pv .notesbox p, .pv .notesbox li { font-size: 23px; max-width: none; }
.pv .notesbox b { color: #ffe76a; }
.pv .notesbox code { background: #0b0f17; color: #9fe0ff; border-color: #34405a; }
.pv .next code { background: #0b0f17; color: #9fe0ff; border-color: #34405a; }
.pv .side { display: flex; flex-direction: column; gap: 16px; }
.pv .clock { font: 700 56px var(--mono); }
.pv .clock.late { color: #ff8a80; } .pv .clock.ok { color: #7ee2b8; }
.pv .meta { font: 15px var(--mono); color: #8fa1bd; }
.pv .next { background: #1a2130; border-radius: 10px; padding: 14px 18px; font-size: 18px; }
.pv button { font: 600 18px var(--body); padding: 12px; border-radius: 8px; border: 0; cursor: pointer; }