/* ============================================================
   Hexscii LLC — site styles
   Technical, precise system: cool paper, hairline rules,
   letterspaced caps, mono numerics. Light/dark via [data-theme].
   ============================================================ */

/* ---------- Self-hosted fonts (subset from Google Fonts; font-display: swap) ---------- */

@font-face {
  font-family: "IBM Plex Mono";
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url("../fonts/ibm-plex-mono-400-latin-ext.woff2") format("woff2");
  unicode-range: U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;
}

@font-face {
  font-family: "IBM Plex Mono";
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url("../fonts/ibm-plex-mono-400-latin.woff2") format("woff2");
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}

@font-face {
  font-family: "IBM Plex Mono";
  font-style: normal;
  font-weight: 500;
  font-display: swap;
  src: url("../fonts/ibm-plex-mono-500-latin-ext.woff2") format("woff2");
  unicode-range: U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;
}

@font-face {
  font-family: "IBM Plex Mono";
  font-style: normal;
  font-weight: 500;
  font-display: swap;
  src: url("../fonts/ibm-plex-mono-500-latin.woff2") format("woff2");
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}

@font-face {
  font-family: "Space Grotesk";
  font-style: normal;
  font-weight: 400 700;
  font-display: swap;
  src: url("../fonts/space-grotesk-400-700-latin-ext.woff2") format("woff2");
  unicode-range: U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;
}

@font-face {
  font-family: "Space Grotesk";
  font-style: normal;
  font-weight: 400 700;
  font-display: swap;
  src: url("../fonts/space-grotesk-400-700-latin.woff2") format("woff2");
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}

:root,
:root[data-theme="light"] {
  color-scheme: light;
  --paper: #f7f8fa;
  --paper-2: #edeff3;
  --ink: #14171c;
  --muted: #5c6470;
  --line: #dde0e6;
  --line-strong: #14171c;
  --accent: #1b5fd9;
  --accent-strong: #1b5fd9;
  --font-body: "Space Grotesk", system-ui, -apple-system, "Helvetica Neue", sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --paper: #101317;
  --paper-2: #171b21;
  --ink: #e9edf2;
  --muted: #98a2b0;
  --line: #2a2f37;
  --line-strong: #e9edf2;
  --accent: #5b9bff;
  --accent-strong: #1b5fd9;
}

/* ---------- Reset & base ---------- */

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  overflow-x: clip;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.65;
  background: var(--paper);
  color: var(--ink);
  -webkit-font-smoothing: antialiased;
  transition: background-color 0.25s ease, color 0.25s ease;
}

h1,
h2,
h3 {
  font-family: var(--font-body);
  font-weight: 700;
  line-height: 1.07;
  letter-spacing: -0.03em;
  margin: 0 0 1.25rem;
  overflow-wrap: break-word;
}

h1 {
  font-size: clamp(2rem, 6vw, 4.4rem);
}

h2 {
  font-size: clamp(1.85rem, 3.5vw, 2.85rem);
}

h3 {
  font-size: 1.18rem;
  letter-spacing: -0.015em;
}

p {
  margin: 0 0 1rem;
}

p:last-child {
  margin-bottom: 0;
}

ul,
ol {
  margin: 0;
  padding: 0;
  list-style: none;
}

a {
  color: inherit;
  text-decoration: none;
}

img {
  max-width: 100%;
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

[id] {
  scroll-margin-top: 96px;
}

::selection {
  background: var(--accent);
  color: #fff;
}

.container {
  width: 100%;
  max-width: 1240px;
  margin-inline: auto;
  padding-inline: clamp(1.25rem, 4vw, 3rem);
}

.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  z-index: 100;
  background: var(--ink);
  color: var(--paper);
  font-weight: 600;
  padding: 0.7rem 1.1rem;
}

.skip-link:focus {
  left: 0;
}

/* Mono is the "engineering" voice: labels, numbers, meta */
.label {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 500;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--muted);
}

.mono {
  font-family: var(--font-mono);
  font-weight: 500;
  letter-spacing: 0;
}

.accent {
  color: var(--accent);
}

.lede {
  font-size: 1.15rem;
  line-height: 1.6;
  color: var(--muted);
  max-width: 60ch;
}

.visually-hidden {
  position: absolute !important;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

/* ---------- Buttons ---------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  padding: 0.95rem 1.75rem;
  border: 1px solid var(--line-strong);
  background: transparent;
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 500;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  cursor: pointer;
  transition: background-color 0.18s ease, color 0.18s ease, border-color 0.18s ease;
}

.btn:hover {
  background: var(--ink);
  color: var(--paper);
}

.btn-solid {
  background: var(--accent-strong);
  border-color: var(--accent-strong);
  color: #fff;
}

.btn-solid:hover {
  background: transparent;
  color: var(--ink);
  border-color: var(--line-strong);
}

.btn-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.9rem;
  margin-top: 2.25rem;
}

.text-link {
  font-weight: 600;
  text-decoration: underline;
  text-underline-offset: 4px;
  text-decoration-thickness: 1px;
}

.text-link:hover {
  color: var(--accent);
}

button[disabled] {
  opacity: 0.55;
  cursor: progress;
}

/* ---------- Header ---------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in srgb, var(--paper) 88%, transparent);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--line);
  transition: background-color 0.25s ease;
}

.header-grid {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  height: 74px;
}

.brand {
  display: inline-flex;
  align-items: center;
  line-height: 0;
}

.brand-logo {
  display: block;
  height: 34px;
  width: auto;
}

/* The mark is pure black artwork — invert it for the dark theme */
[data-theme="dark"] .brand-logo {
  filter: invert(1);
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 1.75rem;
}

.site-nav a {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 500;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
  padding: 0.3rem 0;
  transition: color 0.15s ease;
}

.site-nav a:hover {
  color: var(--ink);
}

.site-nav a[aria-current="page"] {
  color: var(--ink);
  border-bottom: 2px solid var(--accent);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.header-cta {
  display: inline-flex;
  align-items: center;
  padding: 0.68rem 1.1rem;
  background: var(--accent-strong);
  color: #fff;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  font-weight: 500;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  white-space: nowrap;
  transition: opacity 0.18s ease;
}

.header-cta:hover {
  opacity: 0.86;
}

.theme-toggle,
.nav-toggle {
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  padding: 0;
  background: transparent;
  border: 1px solid var(--line);
  color: var(--ink);
  cursor: pointer;
  transition: background-color 0.18s ease, color 0.18s ease, border-color 0.18s ease;
}

.theme-toggle:hover,
.nav-toggle:hover {
  border-color: var(--line-strong);
  background: var(--paper-2);
}

.theme-toggle .icon-sun {
  display: none;
}

[data-theme="dark"] .theme-toggle .icon-sun {
  display: block;
}

[data-theme="dark"] .theme-toggle .icon-moon {
  display: none;
}

.nav-toggle {
  display: none;
}

.nav-toggle .icon-close {
  display: none;
}

.nav-toggle.open .icon-close {
  display: block;
}

.nav-toggle.open .icon-menu {
  display: none;
}

/* ---------- Hero (dark technical band, no photography needed) ---------- */

.hero {
  position: relative;
  overflow: hidden;
  background: #0d1014;
  color: #fff;
  padding: clamp(4rem, 9vw, 7.5rem) 0 clamp(3.5rem, 7vw, 6rem);
}

.hero-grid-bg {
  position: absolute;
  inset: 0;
  z-index: 0;
  color: #7f8b9e;
  opacity: 0.16;
  pointer-events: none;
}

/* accent glow anchored behind the headline */
.hero::after {
  content: "";
  position: absolute;
  top: -22%;
  right: -8%;
  width: 46rem;
  height: 46rem;
  border-radius: 50%;
  background: radial-gradient(
    circle,
    rgba(27, 95, 217, 0.34) 0%,
    rgba(27, 95, 217, 0.12) 42%,
    transparent 68%
  );
  z-index: 0;
  pointer-events: none;
}

.hero > .container {
  position: relative;
  z-index: 1;
}

.hero-inner {
  max-width: 900px;
}

.hero .label {
  color: #94a3b8;
  margin-bottom: 1.5rem;
}

.hero h1 {
  color: #fff;
}

.hero .lede {
  color: rgba(255, 255, 255, 0.82);
}

.hero .btn {
  border-color: rgba(255, 255, 255, 0.7);
  color: #fff;
}

.hero .btn:hover {
  background: #fff;
  color: #0d1014;
}

.hero .btn-solid {
  background: var(--accent-strong);
  border-color: var(--accent-strong);
  color: #fff;
}

.hero .btn-solid:hover {
  background: transparent;
  border-color: #fff;
  color: #fff;
}

.hero-sub {
  padding: clamp(3.25rem, 7vw, 5rem) 0 clamp(2.5rem, 5vw, 3.5rem);
}

.hero-sub h1 {
  font-size: clamp(1.9rem, 5vw, 3.4rem);
}

/* eyebrow chip above the headline */
.chip {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  padding: 0.4rem 0.85rem;
  border: 1px solid rgba(255, 255, 255, 0.22);
  background: rgba(255, 255, 255, 0.05);
  font-family: var(--font-mono);
  font-size: 0.66rem;
  font-weight: 500;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.86);
  margin-bottom: 1.4rem;
}

.chip .dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: #5b9bff;
}

/* ---------- Stat band ---------- */

.stat-band {
  padding-block: clamp(2.25rem, 4.5vw, 3.25rem);
}

.stat-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  border-top: 1px solid var(--line-strong);
  border-bottom: 1px solid var(--line-strong);
}

.stat {
  padding: 1.5rem 1.5rem 1.5rem 0;
  border-left: 1px solid var(--line);
  padding-left: 1.5rem;
}

.stat:first-child {
  border-left: 0;
  padding-left: 0;
}

.stat-num {
  font-family: var(--font-mono);
  font-size: clamp(1.7rem, 3vw, 2.4rem);
  font-weight: 500;
  letter-spacing: -0.02em;
  line-height: 1.1;
}

.stat-label {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  font-weight: 400;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted);
  margin-top: 0.45rem;
}

/* ---------- Ticker ---------- */

.ticker {
  overflow: hidden;
  border-top: 1px solid var(--line-strong);
  border-bottom: 1px solid var(--line-strong);
  padding: 0.8rem 0;
}

.ticker-track {
  display: flex;
  width: max-content;
  animation: ticker 42s linear infinite;
}

.ticker-track span {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  font-weight: 500;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  white-space: nowrap;
  padding-right: 3.25rem;
}

.ticker-track span::after {
  content: "▪";
  color: var(--accent);
  margin-left: 3.25rem;
  font-size: 0.6rem;
  vertical-align: middle;
}

@keyframes ticker {
  to {
    transform: translateX(-50%);
  }
}

@media (prefers-reduced-motion: reduce) {
  .ticker-track {
    animation: none;
  }
}

/* ---------- Sections ---------- */

.section {
  padding: clamp(3.5rem, 7vw, 6rem) 0;
}

.section-alt {
  background: var(--paper-2);
}

.section-head {
  display: flex;
  align-items: baseline;
  gap: 1.5rem;
  border-bottom: 1px solid var(--line-strong);
  padding-bottom: 1.25rem;
  margin-bottom: clamp(2rem, 4vw, 3.5rem);
}

.section-head .num {
  font-family: var(--font-mono);
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--accent);
}

.section-head h2 {
  margin: 0;
}

.section-head .label {
  margin-left: auto;
  text-align: right;
}

/* ---------- Index rows (services as a table of contents) ---------- */

.index-list {
  border-top: 1px solid var(--line-strong);
}

.index-row {
  display: grid;
  grid-template-columns: 4.5rem 1.1fr 1.6fr auto;
  gap: 1.5rem;
  align-items: baseline;
  padding: 1.9rem 0;
  border-bottom: 1px solid var(--line);
  transition: padding-left 0.2s ease;
}

.index-list .index-row:last-child {
  border-bottom: 1px solid var(--line-strong);
}

a.index-row:hover {
  padding-left: 0.75rem;
}

a.index-row:hover .row-arrow {
  color: var(--accent);
}

.row-num {
  font-family: var(--font-mono);
  font-size: 0.95rem;
  color: var(--accent);
}

.row-title {
  font-size: clamp(1.15rem, 2.2vw, 1.55rem);
  font-weight: 700;
  letter-spacing: -0.025em;
}

.row-body {
  color: var(--muted);
  margin: 0;
}

.row-meta {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.66rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted);
  margin-top: 0.75rem;
}

.row-arrow {
  font-size: 1.3rem;
  line-height: 1;
  transition: color 0.15s ease;
}

/* ---------- Split ---------- */

.split {
  display: grid;
  grid-template-columns: 1fr 1.4fr;
  gap: clamp(2rem, 5vw, 4.5rem);
  align-items: start;
}

.split-sticky {
  position: sticky;
  top: 100px;
}

.split p {
  color: var(--muted);
}

/* ---------- Point list ---------- */

.point-list li {
  display: grid;
  grid-template-columns: 3rem 1fr;
  gap: 1.25rem;
  padding: 1.5rem 0;
  border-top: 1px solid var(--line);
}

.point-list li:last-child {
  border-bottom: 1px solid var(--line);
}

.point-list .num {
  font-family: var(--font-mono);
  color: var(--accent);
  font-size: 0.9rem;
}

.point-list h3 {
  margin-bottom: 0.4rem;
}

.point-list p {
  color: var(--muted);
  margin: 0;
}

/* ---------- Cards ---------- */

.card-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: clamp(1.25rem, 2.5vw, 1.75rem);
}

.card {
  display: flex;
  flex-direction: column;
  padding: clamp(1.5rem, 3vw, 2rem);
  border: 1px solid var(--line);
  background: var(--paper);
  transition: border-color 0.18s ease, transform 0.18s ease;
}

.card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}

.card-icon {
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  margin-bottom: 1.25rem;
  border: 1px solid var(--line);
  color: var(--accent);
}

.card h3 {
  margin-bottom: 0.5rem;
}

.card p {
  color: var(--muted);
  font-size: 0.95rem;
  margin: 0;
}

/* ---------- Spec list ---------- */

.spec-list {
  border: 1px solid var(--line-strong);
  padding: 0 1.75rem;
}

.spec-list div {
  display: grid;
  grid-template-columns: 1fr 1.4fr;
  gap: 1rem;
  padding: 1.1rem 0;
  border-bottom: 1px solid var(--line);
}

.spec-list div:last-child {
  border-bottom: 0;
}

.spec-list dt {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
  align-self: center;
}

.spec-list dd {
  margin: 0;
  font-weight: 500;
}

/* ---------- Steps ---------- */

.steps {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  border-top: 1px solid var(--line-strong);
  border-bottom: 1px solid var(--line-strong);
}

.step {
  padding: 1.75rem 1.5rem 1.75rem 0;
  border-left: 1px solid var(--line);
  padding-left: 1.5rem;
}

.step:first-child {
  border-left: 0;
  padding-left: 0;
}

.step-num {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  font-weight: 500;
  color: var(--accent);
  line-height: 1;
  margin-bottom: 0.9rem;
}

.step h3 {
  font-size: 1rem;
  margin-bottom: 0.4rem;
}

.step p {
  color: var(--muted);
  font-size: 0.95rem;
  margin: 0;
}

/* ---------- Check list ---------- */

.check-list li {
  position: relative;
  padding: 0.55rem 0 0.55rem 1.6rem;
  color: var(--muted);
}

.check-list li::before {
  content: "▪";
  position: absolute;
  left: 0;
  color: var(--accent);
  font-size: 0.7rem;
  top: 0.85rem;
}

/* ---------- Inverted CTA ---------- */

.invert {
  background: var(--ink);
  color: var(--paper);
  padding: clamp(3.5rem, 7vw, 5.5rem) 0;
}

.invert .label,
.invert p {
  color: color-mix(in srgb, var(--paper) 70%, var(--ink));
}

.invert .label {
  display: block;
  margin-bottom: 1.5rem;
}

.invert h2 {
  color: var(--paper);
  max-width: 24ch;
}

.invert .btn {
  border-color: var(--paper);
  color: var(--paper);
}

.invert .btn:hover {
  background: var(--paper);
  color: var(--ink);
}

.invert .btn-solid {
  background: var(--accent-strong);
  border-color: var(--accent-strong);
  color: #fff;
}

.invert .btn-solid:hover {
  background: transparent;
  border-color: var(--paper);
  color: var(--paper);
}

.aside-note {
  border-left: 2px solid var(--accent);
  padding: 0.35rem 0 0.35rem 1.25rem;
  color: var(--muted);
  font-size: 0.95rem;
  max-width: 70ch;
}

/* ---------- Forms ---------- */

.form-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.4rem;
}

.field-full {
  grid-column: 1 / -1;
}

.field label {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 0.5rem;
}

.field .req {
  color: var(--accent);
}

input,
select,
textarea {
  width: 100%;
  font: inherit;
  color: var(--ink);
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 0;
  padding: 0.85rem 1rem;
}

textarea {
  min-height: 160px;
  resize: vertical;
}

input:focus,
select:focus,
textarea:focus {
  outline: 2px solid var(--accent);
  outline-offset: 0;
  border-color: var(--accent);
}

.form-status {
  color: var(--accent);
  font-size: 0.95rem;
  min-height: 1.4em;
  margin-top: 0.9rem;
}

.form-status.is-ok {
  color: var(--ink);
}

.form-status.is-error {
  color: #c0392b;
}

[data-theme="dark"] .form-status.is-error {
  color: #ff8a80;
}

/* ---------- Footer ---------- */

.site-footer {
  border-top: 1px solid var(--line-strong);
  padding-top: clamp(2.5rem, 5vw, 4rem);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.3fr 1fr 1fr 1fr;
  gap: 2rem;
}

.footer-brand img {
  display: block;
  height: 32px;
  width: auto;
  margin-bottom: 1rem;
}

[data-theme="dark"] .footer-brand img {
  filter: invert(1);
}

.footer-brand p {
  color: var(--muted);
  font-size: 0.92rem;
  max-width: 30ch;
}

.footer-col h3 {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  font-weight: 500;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 1.1rem;
}

.footer-col li {
  margin-bottom: 0.6rem;
  font-size: 0.94rem;
}

.footer-col a:hover {
  color: var(--accent);
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 0.5rem 2rem;
  margin-top: clamp(2rem, 4vw, 3rem);
  padding: 1.4rem 0;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.85rem;
}

.footer-bottom p {
  margin: 0;
}

/* ---------- 404 ---------- */

.error-wrap {
  min-height: 55vh;
  display: grid;
  place-items: center;
  text-align: center;
  padding: 5rem 0;
}

.error-code {
  font-family: var(--font-mono);
  font-size: clamp(5rem, 16vw, 9rem);
  font-weight: 500;
  letter-spacing: -0.04em;
  line-height: 1;
  color: var(--accent);
}

/* ---------- Responsive ---------- */

@media (max-width: 1040px) {
  .header-cta {
    display: none;
  }

  .card-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 960px) {
  .nav-toggle {
    display: grid;
  }

  /* Full-bleed panel; links carry the container gutter so they line up
     with the logo above them. */
  .site-nav {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: var(--paper);
    border-bottom: 1px solid var(--line-strong);
    padding: 0 0 1.35rem;
    box-shadow: 0 30px 40px -28px rgba(0, 0, 0, 0.5);
  }

  .site-nav.open {
    display: flex;
  }

  .site-nav a {
    padding: 1.05rem clamp(1.25rem, 4vw, 3rem);
    border-top: 1px solid var(--line);
    font-size: 0.78rem;
    color: var(--ink);
    transition: color 0.15s ease, background-color 0.15s ease;
  }

  .site-nav > a:first-child {
    border-top: 0;
  }

  .site-nav a:hover {
    color: var(--accent);
    background: var(--paper-2);
  }

  .site-nav a[aria-current="page"] {
    border-bottom: 0;
    color: var(--accent);
    box-shadow: inset 3px 0 0 var(--accent);
  }

  .split {
    grid-template-columns: 1fr;
  }

  .split-sticky {
    position: static;
  }

  .steps {
    grid-template-columns: 1fr 1fr;
  }

  .step {
    border-left: 0;
    padding-left: 0;
    border-top: 1px solid var(--line);
  }

  .step:first-child,
  .step:nth-child(2) {
    border-top: 0;
  }

  .stat-row {
    grid-template-columns: 1fr 1fr;
  }

  .stat {
    border-left: 0;
    padding-left: 0;
    border-top: 1px solid var(--line);
  }

  .stat:first-child,
  .stat:nth-child(2) {
    border-top: 0;
  }

  .index-row {
    grid-template-columns: 3rem 1fr auto;
  }

  .index-row .row-body {
    grid-column: 2 / 3;
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 720px) {
  .card-grid {
    grid-template-columns: 1fr;
  }

  .form-grid {
    grid-template-columns: 1fr;
  }

  .index-row {
    grid-template-columns: 1fr auto;
    gap: 0.5rem 1rem;
  }

  .row-num {
    grid-column: 1 / -1;
  }

  .index-row .row-body {
    grid-column: 1 / 2;
  }

  .spec-list div {
    grid-template-columns: 1fr;
    gap: 0.25rem;
  }

  .section-head {
    flex-wrap: wrap;
    gap: 0.75rem 1.5rem;
  }

  .section-head .label {
    margin-left: 0;
    text-align: left;
  }
}

@media (max-width: 640px) {
  .header-grid {
    height: 60px;
  }

  .brand-logo {
    height: 26px;
  }

  .theme-toggle,
  .nav-toggle {
    width: 36px;
    height: 36px;
  }

  [id] {
    scroll-margin-top: 74px;
  }

  .hero {
    padding: clamp(3rem, 10vw, 4rem) 0 clamp(2.5rem, 8vw, 3.5rem);
  }

  .hero::after {
    width: 26rem;
    height: 26rem;
  }

  .btn-row {
    gap: 0.75rem;
  }

  .btn-row .btn {
    width: 100%;
  }

  .section {
    padding: 2.75rem 0;
  }

  .section-head {
    margin-bottom: 1.75rem;
  }

  .index-row {
    padding: 1.4rem 0;
  }

  .lede {
    font-size: 1.03rem;
  }

  .invert {
    padding: 3rem 0;
  }
}

@media (max-width: 520px) {
  .steps {
    grid-template-columns: 1fr;
  }

  .step:nth-child(2) {
    border-top: 1px solid var(--line);
  }

  .stat-row {
    grid-template-columns: 1fr;
  }

  .stat:nth-child(2) {
    border-top: 1px solid var(--line);
  }

  .footer-grid {
    grid-template-columns: 1fr;
  }
}