diff --git a/docs/Website/Assets/guru.svg b/docs/Website/Assets/guru.svg new file mode 100644 index 0000000..a9d4ed4 --- /dev/null +++ b/docs/Website/Assets/guru.svg @@ -0,0 +1,12 @@ + + Guru — the PSOGM face + The crash-screen face. Chamfered corners quote the old SchOS letterforms. + Drawn here for reference only: kernel/core/panic.c builds it from primitives + rather than from a bitmap, so it scales with the display and costs nothing in + the kernel image. + + + + + + diff --git a/docs/Website/Assets/shift.svg b/docs/Website/Assets/shift.svg new file mode 100644 index 0000000..ed9d5ba --- /dev/null +++ b/docs/Website/Assets/shift.svg @@ -0,0 +1,27 @@ + + SchOS — Shift + Three slabs, displaced. The layer diagram in docs/architecture/README.md + as a solid object, and the kernel's name (SchIFT) as a shape. + + Each slab shows three faces: the top, the front edge under its lower side, and + the right-end wall under its right diagonal. The right wall is not optional -- + without it the slab has no thickness where it is widest, and the corner reads + as a hole rather than an edge. + + Geometry is shared with "shift-mask.svg"; see that file. + + + + + + + + + + + + + + + + diff --git a/docs/Website/Assets/uberblock.svg b/docs/Website/Assets/uberblock.svg new file mode 100644 index 0000000..ff67457 --- /dev/null +++ b/docs/Website/Assets/uberblock.svg @@ -0,0 +1,44 @@ + + SchFS — Uberblock + The uberblock ring: slots written round-robin, one of them newest. + Mount takes the highest-numbered slot that validates, which is the whole + consistency argument for the format. + + Every slot is an explicit annular sector. An earlier version drew them with + stroke-dasharray on a circle, which is shorter to write and wrong in two ways: + a dash centred on the path start straddles the closure and renders as TWO + pieces with a seam between them, and the normal slot underneath the marked one + still drew, showing through. Neither can happen here -- the marked slot is one + shape and the slot it replaces is simply not emitted. + + 12 slots at 20 degrees of ink and 10 of gap, which closes at 360 exactly. The + marked slot is index 1, counting clockwise from the top. + + It is marked twice over: it carries the accent, the same colour as the root at + the centre, and it reaches outward past the ring while sharing the inner edge + with every other slot. The colour is the reading on screen; the size is what + survives include/logo.h, which is a single coverage channel and keeps no + colour at all. + + Stands alone, with no reference to SchOS, as projects/schfs-linux/README.md + requires. + + + + + + + + + + + + + + + + + + + + diff --git a/docs/Website/README.md b/docs/Website/README.md new file mode 100644 index 0000000..4007a92 --- /dev/null +++ b/docs/Website/README.md @@ -0,0 +1,50 @@ + +# The website + +Three files and a folder of marks. No build step, no dependencies, no +framework — open `index.html` and it works, including from a `file://` URL. + +``` +index.html the page +style.css the palette, transcribed from include/theme.h +app.js two behaviours: the boot log types, sections fade in +Assets/ shift.svg (the logo), uberblock.svg (SchFS), guru.svg (PSOGM) +``` + +## The rules it follows + +**The palette is not a design decision.** It is `include/theme.h`, copied. A +site describing an operating system should look like the operating system, and +copying the header means the two cannot drift apart by accident. + +**PSOGM purple appears exactly once.** `#4B1D9A` is on the crash-screen section +and nowhere else, because [../branding/README.md](../branding/README.md) says +it means *the machine stopped* and that a colour used everywhere means nothing. +If it shows up in a second place, that is a bug in the page. + +**The typefaces are the ones the OS ships.** Roboto for text and JetBrains Mono +for the system voice — both already in `ports/`, both already in `NOTICE`. They +are requested from the system rather than downloaded: a font file would be +larger than the entire rest of the site. + +**The script is optional.** If `app.js` fails to load the page is still +complete and still readable. Everything it does is decoration, and it honours +`prefers-reduced-motion` by doing none of it. + +**The boot log is real.** The lines in `app.js` are from an actual boot, not +invented. The timer calibration line is there deliberately; see section 13 of +[../history/kernel.md](../history/kernel.md) for what it cost. + +## Editing it + +The numbers in the *Numbers* section are measured, not estimated, and they go +stale. To refresh them: + +```sh +find kernel include -name '*.c' -o -name '*.h' | xargs wc -l | tail -1 +grep -c '^SYSCALL' kernel/sys/table.inc +``` + +The feature cards carry a tag — `runs`, `in progress`, or `designed` — and the +tag is a promise. Anything marked `runs` is in the tree and works today. When +that stops being true, change the tag rather than the wording. diff --git a/docs/Website/app.js b/docs/Website/app.js new file mode 100644 index 0000000..3198b19 --- /dev/null +++ b/docs/Website/app.js @@ -0,0 +1,92 @@ +/* SPDX-License-Identifier: Apache-2.0 + * + * Two behaviours, no framework: + * 1. the hero console types a real boot log + * 2. sections fade in once, as they arrive + * + * Both are decoration. If this file fails to load the page is still complete + * and still readable, which is the test any script on a documentation site + * should have to pass. + */ +(function () { + "use strict"; + + var reduced = window.matchMedia && + window.matchMedia("(prefers-reduced-motion: reduce)").matches; + + /* ---- 1. the boot log ------------------------------------------------ + * These are real lines from a real boot, not invented ones. The timer + * calibration line in particular is there because of what it cost: the + * clock ran seven times slow until a graphics driver was made to + * acknowledge its own interrupt. See docs/history/kernel.md. + */ + var LINES = [ + { t: "[ 0.000]", k: "SchIFT", s: " 64-bit, 2 cpus" }, + { t: "[ 0.004]", k: "cpu0", s: ": lapic timer 999949260 Hz, tsc 3792 MHz" }, + { t: "[ 0.061]", k: "virtio-gpu", s: ": 1280x800, 4000 KB framebuffer, irq 11" }, + { t: "[ 0.088]", k: "e1000", s: ": 52:54:00:12:34:56, link up, irq 11" }, + { t: "[ 0.143]", k: "schfs0", s: ": mounted, generation 41" }, + { t: "[ 0.169]", k: "net", s: ": eth0 10.0.2.15/255.255.255.0" }, + { t: "[ 0.204]", k: "schinit", s: ": 4 jobs", g: true }, + { t: "", k: "", s: "# " } + ]; + + var out = document.getElementById("bootlog"); + + function span(cls, text) { + var e = document.createElement("span"); + if (cls) e.className = cls; + e.textContent = text; + return e; + } + + function emit(line) { + if (line.t) { + out.appendChild(span("t", line.t + " ")); + out.appendChild(span("k", line.k)); + } + out.appendChild(span(line.g ? "g" : "", line.s)); + out.appendChild(document.createTextNode("\n")); + } + + function cursor() { + var c = document.createElement("i"); + c.className = "cursor"; + out.appendChild(c); + } + + if (!out) { + /* nothing to do */ + } else if (reduced) { + LINES.forEach(emit); // the whole log at once, no animation + cursor(); + } else { + var i = 0; + (function step() { + if (i >= LINES.length) { cursor(); return; } + emit(LINES[i++]); + /* Uneven on purpose: a boot that ticks out at a metronome's pace reads + as a progress bar rather than as a machine doing different work. */ + setTimeout(step, 180 + Math.random() * 220); + })(); + } + + /* ---- 2. reveal on scroll ------------------------------------------ */ + + var targets = document.querySelectorAll(".reveal"); + + if (reduced || !("IntersectionObserver" in window)) { + Array.prototype.forEach.call(targets, function (el) { el.classList.add("in"); }); + return; + } + + var io = new IntersectionObserver(function (entries) { + entries.forEach(function (entry) { + if (!entry.isIntersecting) return; + entry.target.classList.add("in"); + io.unobserve(entry.target); // once, not on every scroll past + }); + }, { rootMargin: "0px 0px -12% 0px", threshold: 0.05 }); + + Array.prototype.forEach.call(targets, function (el) { io.observe(el); }); +})(); diff --git a/docs/Website/index.html b/docs/Website/index.html new file mode 100644 index 0000000..619b2a6 --- /dev/null +++ b/docs/Website/index.html @@ -0,0 +1,294 @@ + + + + + +SchOS — a 64-bit operating system written from scratch + + + + + + +
+
+ + + SchOS + + +
+
+ +
+ +
+
+
+

SchOS

+

+ A 64-bit operating system written from scratch — its own kernel, its own + filesystem, its own bootloader. It boots on UEFI, drives real hardware, + and runs unmodified musl and toybox on top. +

+
+ What it has + Where it started +
+
+ +
+
+ ttyS0 + SchIFT +
+ 

+    

+  

+

+
+

+  

+    
Origin

+    
It started as a teaching kernel and stopped being one

+    

+      SchOS began as xv6, MIT's
+      teaching operating system: 32-bit, single core, one filesystem, a few dozen
+      syscalls. Almost none of that survives. What follows is what replaced it.
+    

+
+    

+      

+        First
+        
64-bit, and more than one core

+        

+          Four-level paging, a real SMP bring-up, per-CPU state and a trap path
+          that survives both. This is the part that invalidates most of what a
+          32-bit uniprocessor kernel assumes.
+        

+      

+      

+        Then
+        
Its own filesystem

+        

+          xv6's log-structured filesystem was replaced by SchFS: a
+          copy-on-write B-tree with an uberblock ring, extents and checksummed
+          metadata. A crash leaves either the old tree or the new one.
+        

+      

+      

+        Then
+        
A Linux-shaped ABI

+        

+          The syscall table adopted Linux numbering, which is what makes an
+          unmodified musl and an unmodified toybox run. The table is one
+          .inc file, and it is the seam the whole system is built around.
+        

+      

+      

+        Now
+        
Hardware, not emulation

+        

+          A UEFI loader, xHCI and USB storage, an e1000 with a real TCP/IP stack,
+          virtio-gpu and VBE framebuffers, and a device model where a driver never
+          names its consumer.
+        

+      

+    

+  

+

+
+

+  

+    
Architecture

+    
Two seams hold the whole thing together

+    

+      Above the syscall table, software is ordinary and portable. Below the device
+      model, a driver never names its consumer and a consumer never names a driver.
+      Everything else is arrangement.
+    

+
+    

+      
userlandtoybox, mksh, musl, and the first-party programs in cmd/

+      
schinitPID 1 — job manifests and supervision

+      
syscall tableLinux numbering, one .inc file — the ABI seam

+      
kernel servicesVFS, sockets, signals, mmap, poll, procfs

+      
subsystemsSchFS, lwIP, text and graphics, the buffer cache

+      
device modelclass vtables and bus binding — the driver seam

+      
driversxHCI, e1000, virtio-gpu, VBE, IDE, PS/2

+      
SchIFT corescheduler, paging, traps, IRQ, SMP, DMA

+      
bootthe UEFI loader in boot/uefi

+    

+
+    

+      uname -s reports SchIFT — the kernel — the way every Unix
+      reports its kernel rather than its distribution.
+    

+  

+

+
+

+  

+    
What it has

+    
Built and running, and honest about the rest

+    

+      Every card marked runs is in the tree and works today. The tags are
+      not aspirational; the things that are not finished say so.
+    

+
+    

+      

+        runs
+        
SchFS

+        

+          Copy-on-write B-tree, a 128-slot uberblock ring, extents with refcounts
+          and reflink, CRC32c on metadata, and free space derived from the tree
+          rather than stored beside it — so there is no second structure to
+          disagree with the first. There is nothing to repair after a crash.
+        

+      

+      

+        runs
+        
SMP x86-64 kernel

+        

+          Four-level paging, multiple cores, preemptive scheduling, a calibrated
+          LAPIC timer, real signal delivery and job control. 205 syscalls on
+          Linux numbering.
+        

+      

+      

+        runs
+        
Networking

+        

+          An e1000 driver under lwIP, with sockets for AF_INET, AF_UNIX and
+          AF_NETLINK. DHCP brings the interface up at boot; ping
+          reaches the outside world.
+        

+      

+      

+        runs
+        
UEFI boot

+        

+          A PE/COFF loader built with clang and lld-link that sets up its own page
+          tables and hands the kernel a framebuffer. No BIOS path, no chainloading.
+        

+      

+      

+        runs
+        
USB

+        

+          xHCI, hubs, HID and mass storage — a keyboard and a USB disk that the
+          kernel can mount, through the same device model as everything else.
+        

+      

+      

+        runs
+        
A real userland

+        

+          musl and toybox, both unmodified, plus mksh as /bin/sh.
+          fastfetch builds from upstream source with an empty
+          patches/ directory — when it could not detect something, the
+          answer was to give the kernel what it was looking for.
+        

+      

+      

+        in progress
+        
Schcom

+        

+          The compositor that will own the display. v0 runs. The desktop above it
+          is the next large piece of work, and it is deliberately Wayland-shaped.
+        

+      

+      

+        designed
+        
SchAPI

+        

+          The native programming interface — specified, not built, and deliberately
+          so. It should be designed from the compositor's experience rather
+          than before it.
+        

+      

+    

+  

+

+
+

+  

+    
Numbers

+    
The size of it

+    

+      
43,701lines in kernel/ and include/

+      
205syscalls, Linux numbering

+      
128uberblock ring slots

+      
0patches carried against fastfetch

+    

+  

+

+
+

+  

+    Guru, the SchOS crash-screen icon
+    

+      
When it stops

+      
PSOGM

+      

+        When the kernel panics it does not scroll a stack trace past you. It draws
+        a full-screen report — what failed, where, and the state that mattered —
+        and encodes the whole thing as a QR code so it can leave the machine
+        without being retyped.
+      

+      

+        This purple is #4B1D9A, and the theme reserves it for exactly
+        this. Normal states are calm and dark; only failure is loud. It is the one
+        colour in the system that means something, which is why it appears once on
+        this page and nowhere else.
+      

+    

+  

+

+
+

+  

+    
Reading

+    
Where to look

+    

+      The documentation is written to outlive the work. Anything finished is
+      described in architecture/; anything intended lives in
+      plan/; and the bugs worth remembering are kept in
+      history/, in full, including the wrong turns.
+    

+    

+      
+        ArchitectureWhat the system is, layer by layer
+      
+      
+        The 1.0 definitionWhat is in, what is out, and why
+      
+      
+        Kernel historyThe bugs, and what each one taught
+      
+      
+        Building itToolchain, ports, and running under QEMU
+      
+    

+  

+

+
+

+
+
+
+
+
+
diff --git a/docs/Website/style.css b/docs/Website/style.css
new file mode 100644
index 0000000..a795708
--- /dev/null
+++ b/docs/Website/style.css
@@ -0,0 +1,371 @@
+/* SPDX-License-Identifier: Apache-2.0
+ *
+ * The palette is not chosen here. It is include/theme.h, transcribed, because
+ * a site that describes an operating system should look like the operating
+ * system. That includes the rule theme.h enforces:
+ *
+ *   normal states are calm and dark; only failure is loud.
+ *
+ * PSOGM purple (--psogm) therefore appears exactly once on this page, in the
+ * crash-screen section. If it ever appears anywhere else, delete it there.
+ */
+
+:root {
+  /* include/theme.h */
+  --bg:         #0C0E13;   /* SCH_BG */
+  --fg:         #E6E8EC;   /* SCH_FG */
+  --dim:        #707784;   /* SCH_DIM */
+  --accent:     #7C5CFF;   /* SCH_ACCENT */
+  --accent-dim: #2A2440;   /* SCH_ACCENT_DIM */
+  --ok:         #4ADE80;   /* SCH_OK */
+  --warn:       #FBBF24;   /* SCH_WARN */
+  --psogm:      #4B1D9A;   /* PSOGM_BG — failure, and nothing else */
+
+  /* Surfaces lifted off the ground, keeping its blue bias rather than
+     sliding toward neutral grey. */
+  --surface:    #12151C;
+  --surface-2:  #171B24;
+  --line:       #212632;
+
+  --sans: "Roboto", ui-sans-serif, system-ui, -apple-system, "Segoe UI", sans-serif;
+  --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, "Cascadia Code",
+          Menlo, Consolas, monospace;
+
+  --measure: 66ch;
+  --gap:     clamp(1rem, 2.5vw, 1.75rem);
+  --section: clamp(4rem, 10vw, 7.5rem);
+}
+
+*, *::before, *::after { box-sizing: border-box; }
+
+html { scroll-behavior: smooth; }
+@media (prefers-reduced-motion: reduce) {
+  html { scroll-behavior: auto; }
+}
+
+body {
+  margin: 0;
+  background: var(--bg);
+  color: var(--fg);
+  font-family: var(--sans);
+  font-size: clamp(1rem, 0.95rem + 0.2vw, 1.0625rem);
+  line-height: 1.65;
+  -webkit-font-smoothing: antialiased;
+}
+
+/* ---- shared shells ------------------------------------------------- */
+
+.wrap {
+  width: min(100% - 2.5rem, 68rem);
+  margin-inline: auto;
+}
+
+section { padding-block: var(--section); }
+
+.eyebrow {
+  font-family: var(--mono);
+  font-size: 0.75rem;
+  letter-spacing: 0.14em;
+  text-transform: uppercase;
+  color: var(--accent);
+  margin: 0 0 0.75rem;
+}
+
+h1, h2, h3 { text-wrap: balance; line-height: 1.15; margin: 0; }
+
+h2 {
+  font-size: clamp(1.75rem, 1.3rem + 2vw, 2.75rem);
+  font-weight: 700;
+  letter-spacing: -0.02em;
+}
+
+.lede {
+  max-width: var(--measure);
+  color: var(--dim);
+  font-size: clamp(1.05rem, 1rem + 0.35vw, 1.2rem);
+  margin: 1.25rem 0 0;
+}
+
+p { max-width: var(--measure); }
+
+a { color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 3px; }
+a:hover { color: var(--fg); }
+a:focus-visible,
+button:focus-visible {
+  outline: 2px solid var(--accent);
+  outline-offset: 3px;
+  border-radius: 2px;
+}
+
+code, .mono { font-family: var(--mono); font-size: 0.9em; }
+code { color: var(--fg); background: var(--surface-2); padding: 0.1em 0.4em; border-radius: 3px; }
+
+/* ---- header -------------------------------------------------------- */
+
+header.top {
+  position: sticky;
+  top: 0;
+  z-index: 10;
+  background: color-mix(in srgb, var(--bg) 88%, transparent);
+  backdrop-filter: blur(8px);
+  border-bottom: 1px solid var(--line);
+}
+.top .wrap {
+  display: flex;
+  align-items: center;
+  gap: 1.5rem;
+  padding-block: 0.85rem;
+}
+.brand {
+  display: flex; align-items: center; gap: 0.6rem;
+  font-weight: 700; letter-spacing: -0.01em;
+  color: inherit; text-decoration: none;
+}
+.brand img { width: 26px; height: 26px; display: block; }
+.top nav { margin-left: auto; display: flex; gap: 1.5rem; font-size: 0.9rem; }
+.top nav a { color: var(--dim); text-decoration: none; }
+.top nav a:hover { color: var(--fg); }
+@media (max-width: 46rem) { .top nav { display: none; } }
+
+/* ---- hero ---------------------------------------------------------- */
+
+.hero { padding-block: clamp(3.5rem, 9vw, 6.5rem) var(--section); }
+.hero .wrap {
+  display: grid;
+  grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr);
+  gap: clamp(2rem, 5vw, 4rem);
+  align-items: center;
+}
+@media (max-width: 56rem) {
+  .hero .wrap { grid-template-columns: 1fr; }
+}
+
+.hero h1 {
+  font-size: clamp(2.75rem, 1.8rem + 4.2vw, 4.75rem);
+  font-weight: 700;
+  letter-spacing: -0.035em;
+}
+.hero h1 .mark {
+  display: inline-block;
+  width: 0.95em;
+  height: 0.95em;
+  vertical-align: -0.08em;
+  margin-right: 0.22em;
+}
+.hero p { color: var(--dim); font-size: clamp(1.05rem, 1rem + 0.4vw, 1.25rem); margin-top: 1.25rem; }
+.hero .cta { display: flex; flex-wrap: wrap; gap: 0.75rem; margin-top: 2rem; }
+
+.btn {
+  display: inline-block;
+  padding: 0.65rem 1.25rem;
+  border-radius: 4px;
+  font-size: 0.925rem;
+  font-weight: 500;
+  text-decoration: none;
+  border: 1px solid var(--line);
+  color: var(--fg);
+  background: var(--surface);
+}
+.btn:hover { border-color: var(--accent); color: var(--fg); }
+.btn.primary { background: var(--accent); border-color: var(--accent); color: #0B0714; font-weight: 700; }
+.btn.primary:hover { background: #8F73FF; border-color: #8F73FF; color: #0B0714; }
+
+/* ---- console ------------------------------------------------------- */
+
+.console {
+  background: #090B0F;
+  border: 1px solid var(--line);
+  border-radius: 6px;
+  overflow: hidden;
+  box-shadow: 0 24px 60px -30px #000;
+}
+.console-bar {
+  display: flex;
+  align-items: center;
+  gap: 0.5rem;
+  padding: 0.55rem 0.85rem;
+  border-bottom: 1px solid var(--line);
+  background: var(--surface);
+  font-family: var(--mono);
+  font-size: 0.72rem;
+  color: var(--dim);
+  letter-spacing: 0.06em;
+}
+.console-bar .dot { width: 8px; height: 8px; border-radius: 50%; background: var(--line); }
+.console-bar .dot.live { background: var(--ok); }
+.console-bar span { margin-left: auto; }
+
+.console pre {
+  margin: 0;
+  padding: 1rem 1.1rem 1.4rem;
+  font-family: var(--mono);
+  font-size: clamp(0.72rem, 0.62rem + 0.35vw, 0.82rem);
+  line-height: 1.85;
+  color: var(--fg);
+  overflow-x: auto;
+  min-height: 16.5rem;
+}
+.console .t { color: var(--dim); }
+.console .k { color: var(--accent); }
+.console .g { color: var(--ok); }
+.console .cursor {
+  display: inline-block;
+  width: 0.55em;
+  height: 1.05em;
+  background: var(--accent);
+  vertical-align: -0.18em;
+  animation: blink 1.1s step-end infinite;
+}
+@keyframes blink { 50% { opacity: 0; } }
+@media (prefers-reduced-motion: reduce) { .console .cursor { animation: none; } }
+
+/* ---- origin timeline ----------------------------------------------- */
+
+.origin-grid {
+  display: grid;
+  grid-template-columns: repeat(auto-fit, minmax(15rem, 1fr));
+  gap: var(--gap);
+  margin-top: 3rem;
+}
+.step {
+  border-left: 2px solid var(--accent-dim);
+  padding-left: 1.1rem;
+}
+.step h3 { font-size: 1.05rem; font-weight: 700; margin-bottom: 0.4rem; }
+.step .when { font-family: var(--mono); font-size: 0.72rem; color: var(--accent); letter-spacing: 0.08em; text-transform: uppercase; display: block; margin-bottom: 0.5rem; }
+.step p { color: var(--dim); font-size: 0.925rem; margin: 0; }
+
+/* ---- the stack ----------------------------------------------------- */
+
+.stack { display: flex; flex-direction: column; gap: 3px; margin-top: 3rem; }
+.layer {
+  display: grid;
+  grid-template-columns: 10.5rem 1fr;
+  gap: 1.25rem;
+  align-items: baseline;
+  padding: 0.95rem 1.15rem;
+  background: var(--surface);
+  border: 1px solid transparent;
+  border-radius: 3px;
+}
+.layer:hover { border-color: var(--accent-dim); background: var(--surface-2); }
+.layer .name { font-family: var(--mono); font-size: 0.8rem; color: var(--accent); letter-spacing: 0.04em; }
+.layer .what { color: var(--dim); font-size: 0.9rem; }
+.layer.seam { background: var(--accent-dim); }
+.layer.seam .name { color: var(--fg); }
+.layer.seam .what { color: #C9BEEC; }
+@media (max-width: 42rem) {
+  .layer { grid-template-columns: 1fr; gap: 0.3rem; }
+}
+.seam-note { margin-top: 1.5rem; color: var(--dim); font-size: 0.9rem; }
+
+/* ---- features ------------------------------------------------------ */
+
+.cards {
+  display: grid;
+  grid-template-columns: repeat(auto-fit, minmax(17rem, 1fr));
+  gap: var(--gap);
+  margin-top: 3rem;
+}
+.card {
+  background: var(--surface);
+  border: 1px solid var(--line);
+  border-radius: 5px;
+  padding: 1.4rem;
+  display: flex;
+  flex-direction: column;
+  gap: 0.6rem;
+}
+.card h3 { font-size: 1.05rem; font-weight: 700; }
+.card p { color: var(--dim); font-size: 0.925rem; margin: 0; max-width: none; }
+.card .tag {
+  align-self: flex-start;
+  font-family: var(--mono);
+  font-size: 0.68rem;
+  letter-spacing: 0.1em;
+  text-transform: uppercase;
+  padding: 0.2rem 0.5rem;
+  border-radius: 3px;
+  border: 1px solid var(--line);
+  color: var(--dim);
+}
+.card .tag.runs   { color: var(--ok);   border-color: color-mix(in srgb, var(--ok) 35%, transparent); }
+.card .tag.partial{ color: var(--warn); border-color: color-mix(in srgb, var(--warn) 35%, transparent); }
+.card .tag.planned{ color: var(--dim); }
+
+/* ---- numbers ------------------------------------------------------- */
+
+.figures {
+  display: grid;
+  grid-template-columns: repeat(auto-fit, minmax(9rem, 1fr));
+  gap: var(--gap);
+  margin-top: 3rem;
+}
+.figure { border-top: 1px solid var(--line); padding-top: 1rem; }
+.figure b {
+  display: block;
+  font-family: var(--mono);
+  font-size: clamp(1.6rem, 1.2rem + 1.6vw, 2.25rem);
+  font-weight: 700;
+  font-variant-numeric: tabular-nums;
+  letter-spacing: -0.02em;
+}
+.figure span { color: var(--dim); font-size: 0.85rem; }
+
+/* ---- the crash screen: the one loud thing --------------------------- */
+
+.crash { background: var(--psogm); color: #fff; }
+.crash .wrap {
+  display: grid;
+  grid-template-columns: 8rem minmax(0, 1fr);
+  gap: clamp(1.5rem, 4vw, 3rem);
+  align-items: start;
+}
+@media (max-width: 44rem) { .crash .wrap { grid-template-columns: 1fr; } }
+.crash img { width: 100%; max-width: 8rem; height: auto; }
+.crash .eyebrow { color: #C3AEEC; }
+.crash h2 { color: #fff; }
+.crash p { color: #DBCEF5; }
+.crash code { background: rgba(0, 0, 0, 0.28); color: #fff; }
+
+/* ---- closing links -------------------------------------------------- */
+
+.links { display: grid; grid-template-columns: repeat(auto-fit, minmax(14rem, 1fr)); gap: var(--gap); margin-top: 2.5rem; }
+.link-card {
+  display: block;
+  padding: 1.2rem;
+  border: 1px solid var(--line);
+  border-radius: 5px;
+  text-decoration: none;
+  color: var(--fg);
+  background: var(--surface);
+}
+.link-card:hover { border-color: var(--accent); color: var(--fg); }
+.link-card b { display: block; margin-bottom: 0.3rem; }
+.link-card span { color: var(--dim); font-size: 0.875rem; }
+
+footer {
+  border-top: 1px solid var(--line);
+  padding-block: 2.5rem 3.5rem;
+  color: var(--dim);
+  font-size: 0.85rem;
+}
+footer .wrap { display: flex; flex-wrap: wrap; gap: 1rem 2rem; align-items: center; }
+footer .mono { font-size: 0.78rem; }
+
+/* ---- reveal on scroll ---------------------------------------------- */
+
+.reveal { opacity: 0; transform: translateY(12px); transition: opacity .5s ease, transform .5s ease; }
+.reveal.in { opacity: 1; transform: none; }
+@media (prefers-reduced-motion: reduce) {
+  .reveal { opacity: 1; transform: none; transition: none; }
+}
+
+/* The SchFS mark, set beside its own card heading. Baseline-aligned rather
+   than centred: it sits next to a word, so it follows the word. */
+.card h3 .cardmark {
+  width: 1.15em;
+  height: 1.15em;
+  vertical-align: -0.22em;
+  margin-right: 0.4em;
+}