/* ==========================================================================
   Demigard Guard — demigard.dev
   One stylesheet, no build step, system fonts only.
   Paper #F3F1EC · ink #1F1F1E · one signal colour (amber) for approval.
   ========================================================================== */

:root {
  --paper: #F3F1EC;
  --paper-raised: #FAF8F4;
  --paper-deep: #E9E6DD;
  --ink: #1F1F1E;
  --ink-soft: #55544F;
  --line: #D8D4C8;
  --line-strong: #B7B2A3;
  --amber: #A54B08;
  --amber-tint: #F2E4D3;

  --sans: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, "Noto Sans", sans-serif;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas,
    "Liberation Mono", "Courier New", monospace;

  --gutter: clamp(1.25rem, 5vw, 4rem);
  --block: clamp(3.5rem, 8vw, 6.5rem);

  --fs-h1: clamp(2.55rem, 6.6vw, 4.6rem);
  --fs-h2: clamp(1.6rem, 3.2vw, 2.35rem);
  --fs-lead: clamp(1.06rem, 1.5vw, 1.28rem);
  --fs-body: clamp(1rem, 1.05vw, 1.0625rem);
  --fs-small: 0.875rem;
  --fs-mono: 0.75rem;
}

/* Reset ------------------------------------------------------------------ */

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

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

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: var(--fs-body);
  line-height: 1.6;
  font-synthesis-weight: none;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, p, ol, ul, figure, table { margin: 0; }
ol, ul { padding: 0; list-style: none; }
a { color: inherit; }
svg { display: block; }

:focus-visible {
  outline: 2px solid var(--ink);
  outline-offset: 3px;
  border-radius: 1px;
}

::selection {
  background: var(--ink);
  color: var(--paper);
}

.wrap {
  width: min(1140px, calc(100% - var(--gutter) * 2));
  margin-inline: auto;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

/* Skip link -------------------------------------------------------------- */

.skip {
  position: absolute;
  top: 0;
  left: 0;
  z-index: 10;
  transform: translateY(-120%);
  background: var(--ink);
  color: var(--paper);
  padding: 0.75rem 1.25rem;
  font-family: var(--mono);
  font-size: var(--fs-small);
  text-decoration: none;
}

.skip:focus {
  transform: translateY(0);
  outline-offset: -4px;
  outline-color: var(--paper);
}

/* Shared type ------------------------------------------------------------ */

.eyebrow {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin: 0;
  font-family: var(--mono);
  font-size: var(--fs-mono);
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

.eyebrow__num {
  color: var(--ink);
  font-variant-numeric: tabular-nums;
}

.eyebrow__mark {
  width: 6px;
  height: 6px;
  background: var(--ink);
}

h1 {
  margin-top: 1.25rem;
  font-size: var(--fs-h1);
  font-weight: 600;
  line-height: 1.02;
  letter-spacing: -0.035em;
  text-wrap: balance;
  max-width: 18ch;
}

h2 {
  margin-top: 1.1rem;
  font-size: var(--fs-h2);
  font-weight: 600;
  line-height: 1.15;
  letter-spacing: -0.022em;
  text-wrap: balance;
  max-width: 24ch;
}

h3 {
  text-wrap: balance;
  font-size: 1.0625rem;
  font-weight: 600;
  line-height: 1.35;
  letter-spacing: -0.012em;
}

.lead {
  margin-top: clamp(1.5rem, 2.6vw, 2rem);
  max-width: 57ch;
  font-size: var(--fs-lead);
  line-height: 1.55;
  color: var(--ink-soft);
  text-wrap: pretty;
}

.mono-label {
  font-family: var(--mono);
  font-size: var(--fs-mono);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

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

.site-header {
  border-bottom: 1px solid var(--line);
}

.site-header__inner {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1.5rem;
  padding-block: 1.15rem;
}

.brand {
  font-size: 1.05rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  text-decoration: none;
  white-space: nowrap;
}

.brand__sub {
  margin-left: 0.55em;
  font-family: var(--mono);
  font-size: 0.625rem;
  font-weight: 500;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

.nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 0.35rem 1.35rem;
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.04em;
}

.nav a {
  text-decoration: none;
  color: var(--ink-soft);
  padding-block: 0.35rem;
  border-bottom: 1px solid transparent;
  transition: color 0.15s ease, border-color 0.15s ease;
}

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

/* Hero ------------------------------------------------------------------- */

.hero {
  padding-block: clamp(3.25rem, 7vw, 6.5rem) clamp(3rem, 6vw, 5.5rem);
}

.hero__inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 15rem;
  gap: clamp(2.5rem, 6vw, 5rem);
  align-items: start;
}

.hero__text { min-width: 0; }

.cta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: clamp(2rem, 3.5vw, 2.75rem);
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.6em;
  padding: 0.8rem 1.15rem;
  border: 1px solid var(--ink);
  font-size: 0.9375rem;
  font-weight: 550;
  line-height: 1.2;
  letter-spacing: -0.005em;
  text-decoration: none;
  transition: background-color 0.18s ease, color 0.18s ease;
}

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

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

.btn--ghost {
  background: transparent;
  color: var(--ink);
}

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

.btn__arrow {
  transition: transform 0.18s ease;
}

.btn:hover .btn__arrow { transform: translateX(3px); }

.hero__index {
  padding-top: 0.75rem;
  border-top: 1px solid var(--line-strong);
}

.hero__index .mono-label { padding-left: calc(2.25rem + 0.5rem); }

.hero__index ol { margin-top: 0.5rem; }

.hero__index a {
  display: grid;
  grid-template-columns: 2.25rem 1fr;
  gap: 0.5rem;
  padding-block: 0.55rem;
  border-bottom: 1px solid var(--line);
  font-size: 0.875rem;
  text-decoration: none;
  color: var(--ink);
  transition: color 0.15s ease;
}

.hero__index a:hover { color: var(--amber); }

.hero__index .num {
  font-family: var(--mono);
  font-size: 0.6875rem;
  color: var(--ink-soft);
  padding-top: 0.2em;
  font-variant-numeric: tabular-nums;
}

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

.section {
  padding-block: var(--block);
  border-top: 1px solid var(--line);
}

.section > .wrap > h2 { max-width: 26ch; }

/* Problem ---------------------------------------------------------------- */

.problem {
  margin-top: clamp(2rem, 4vw, 3.25rem);
  border-top: 1px solid var(--line-strong);
}

.problem li {
  display: grid;
  grid-template-columns: 2.5rem minmax(0, 1fr);
  gap: 1rem;
  padding-block: clamp(1.1rem, 2vw, 1.55rem);
  border-bottom: 1px solid var(--line);
}

.problem__num {
  font-family: var(--mono);
  font-size: 0.6875rem;
  color: var(--ink-soft);
  padding-top: 0.55em;
}

.problem p {
  font-size: clamp(1.1rem, 2vw, 1.4rem);
  line-height: 1.45;
  letter-spacing: -0.012em;
  max-width: 52ch;
  text-wrap: pretty;
}

/* Loop diagram ----------------------------------------------------------- */

.loop-figure { margin-top: clamp(2rem, 4vw, 3rem); }

.loop {
  width: 100%;
  height: auto;
  max-width: 1000px;
}

.loop__narrow { display: none; }

.loop .box {
  fill: none;
  stroke: var(--line-strong);
  stroke-width: 1;
}

.loop .box--fill { fill: var(--paper-raised); }

.loop .box--scope {
  fill: none;
  stroke: var(--line);
  stroke-dasharray: 3 4;
}

.loop .gate {
  fill: var(--amber-tint);
  stroke: var(--amber);
  stroke-width: 1.4;
}

.loop .flow {
  fill: none;
  stroke: var(--ink-soft);
  stroke-width: 1.1;
}

.loop .junction { fill: var(--ink-soft); }
.loop .arrowhead { fill: var(--ink-soft); }

.loop .t-label {
  font-family: var(--sans);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: -0.01em;
  fill: var(--ink);
}

.loop .t-sub {
  font-family: var(--mono);
  font-size: 10.5px;
  letter-spacing: 0.02em;
  fill: var(--ink-soft);
}

.loop .t-sub--signal { fill: var(--amber); }
.loop .t-path--signal { fill: var(--amber); }

.loop .t-scope {
  font-family: var(--mono);
  font-size: 9.5px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  fill: var(--ink-soft);
}

.loop .t-path {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.06em;
  fill: var(--ink-soft);
}

.loop-caption {
  margin-top: clamp(1.25rem, 2.5vw, 1.75rem);
  padding-top: 1rem;
  border-top: 1px solid var(--line);
  max-width: 68ch;
  font-size: var(--fs-small);
  line-height: 1.65;
  color: var(--ink-soft);
}

/* Tier table ------------------------------------------------------------- */

.tiers {
  width: 100%;
  margin-top: clamp(2rem, 4vw, 3rem);
  border-collapse: collapse;
  text-align: left;
}

.tiers caption { text-align: left; }

.tiers thead th {
  padding-bottom: 0.7rem;
  border-bottom: 1px solid var(--line-strong);
  font-family: var(--mono);
  font-size: var(--fs-mono);
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

.tiers thead th:first-child { width: 32%; }

.tiers tbody th {
  width: 32%;
  padding: clamp(1rem, 2vw, 1.35rem) 2rem clamp(1rem, 2vw, 1.35rem) 0;
  border-bottom: 1px solid var(--line);
  font-weight: 400;
  vertical-align: top;
  text-align: left;
}

.tiers tbody td {
  padding: clamp(1rem, 2vw, 1.35rem) 0;
  border-bottom: 1px solid var(--line);
  vertical-align: top;
  font-size: clamp(1rem, 1.5vw, 1.15rem);
  line-height: 1.45;
  text-wrap: pretty;
}

.tier {
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 0.6rem;
}

.tier__id {
  font-family: var(--mono);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.04em;
  padding: 0.2rem 0.45rem;
  border: 1px solid var(--line-strong);
  color: var(--ink);
}

.tier__id--signal {
  border-color: var(--amber);
  color: var(--amber);
  background: var(--amber-tint);
}

.tier__class {
  font-size: clamp(1rem, 1.5vw, 1.15rem);
  font-weight: 550;
  letter-spacing: -0.01em;
}

.table-note {
  margin-top: 1.25rem;
  max-width: 60ch;
  font-family: var(--mono);
  font-size: 0.75rem;
  line-height: 1.7;
  color: var(--ink-soft);
}

/* Differentiation -------------------------------------------------------- */

.diff {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin-top: clamp(2rem, 4vw, 3rem);
  border-top: 1px solid var(--line);
  border-left: 1px solid var(--line);
}

.diff__item {
  display: flex;
  flex-direction: column;
  padding: clamp(1.4rem, 3vw, 2.25rem);
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: transparent;
  transition: background-color 0.2s ease;
}

.diff__item:hover { background: var(--paper-raised); }

.diff__num {
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.1em;
  color: var(--ink-soft);
  margin-bottom: 0.9rem;
}

.diff__item > p:not(.diff__num):not(.why) {
  margin-top: 0.65rem;
  max-width: 46ch;
  color: var(--ink-soft);
  text-wrap: pretty;
}

.why {
  margin-top: auto;
  padding-top: 1.1rem;
  border-top: 1px solid var(--line);
  max-width: 46ch;
  font-size: var(--fs-small);
  line-height: 1.6;
}

.why__label {
  display: block;
  margin-bottom: 0.3rem;
  font-family: var(--mono);
  font-size: var(--fs-mono);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink);
}

/* Docs cards ------------------------------------------------------------- */

.docs {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin-top: clamp(2rem, 4vw, 3rem);
  background: var(--line);
  border: 1px solid var(--line);
}

.docs li { background: var(--paper); }

.card {
  display: flex;
  flex-direction: column;
  height: 100%;
  gap: 0.55rem;
  padding: clamp(1.25rem, 2.5vw, 1.75rem);
  text-decoration: none;
  transition: background-color 0.18s ease;
}

.card:hover { background: var(--paper-raised); }

.card__top {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  font-family: var(--mono);
  font-size: 0.6875rem;
  color: var(--ink-soft);
}

.card__arrow {
  font-size: 0.875rem;
  transition: transform 0.18s ease;
}

.card:hover .card__arrow { transform: translateX(3px); }

.card__title {
  font-size: 1.0625rem;
  font-weight: 600;
  letter-spacing: -0.012em;
}

.card__desc {
  font-size: var(--fs-small);
  line-height: 1.6;
  color: var(--ink-soft);
  text-wrap: pretty;
}

.card:hover .card__title { text-decoration: underline; text-underline-offset: 4px; }

/* Status ----------------------------------------------------------------- */

.section--status {
  padding-block: clamp(2.5rem, 5vw, 4rem);
  border-top: 0;
}

.status {
  display: grid;
  grid-template-columns: 5rem minmax(0, 1fr) auto;
  align-items: baseline;
  gap: clamp(1rem, 3vw, 2.5rem);
  border-top: 1px solid var(--ink);
  border-bottom: 1px solid var(--ink);
  padding-block: clamp(1.4rem, 3vw, 2rem);
}

.status__line {
  max-width: 52ch;
  font-size: clamp(1.05rem, 1.8vw, 1.25rem);
  line-height: 1.5;
  letter-spacing: -0.012em;
  text-wrap: pretty;
}

.status__link {
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.04em;
  text-decoration: none;
  border-bottom: 1px solid var(--ink);
  padding-bottom: 0.2rem;
  white-space: nowrap;
}

.status__link:hover { color: var(--amber); border-bottom-color: var(--amber); }

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

.site-footer {
  border-top: 1px solid var(--line);
  padding-block: clamp(2.25rem, 4vw, 3.25rem) clamp(2.5rem, 5vw, 4rem);
}

.site-footer__inner {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: flex-start;
  gap: 2rem;
}

.footer__brand {
  font-weight: 600;
  letter-spacing: -0.015em;
}

.footer__note {
  margin-top: 0.35rem;
  max-width: 42ch;
  font-size: var(--fs-small);
  color: var(--ink-soft);
}

.footer__nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.5rem;
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.04em;
}

.footer__nav a {
  text-decoration: none;
  color: var(--ink-soft);
  border-bottom: 1px solid transparent;
  padding-bottom: 0.15rem;
}

.footer__nav a:hover { color: var(--ink); border-bottom-color: var(--ink); }

.footer__fine {
  margin-top: clamp(2rem, 4vw, 3rem);
  padding-top: 1rem;
  border-top: 1px solid var(--line);
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.02em;
  color: var(--ink-soft);
}

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

@media (max-width: 960px) {
  .hero__inner {
    grid-template-columns: minmax(0, 1fr);
    align-items: start;
  }

  .hero__index {
    max-width: 30rem;
    margin-top: 0.5rem;
  }
}

@media (max-width: 899px) {
  .loop__wide { display: none; }
  .loop__narrow { display: block; }
  .loop__narrow .loop { max-width: 30rem; margin-inline: auto; }
  .loop-caption { max-width: 30rem; margin-inline: auto; }

  .status {
    grid-template-columns: minmax(0, 1fr);
    gap: 1rem;
  }

  .status__link { justify-self: start; }
}

@media (max-width: 640px) {
  .site-header__inner {
    flex-wrap: wrap;
    align-items: center;
    row-gap: 0.5rem;
  }

  .nav { justify-content: flex-start; gap: 0.25rem 1rem; }

  .diff { grid-template-columns: minmax(0, 1fr); }
  .docs { grid-template-columns: minmax(0, 1fr); }

  .tiers thead { display: none; }

  .tiers tr {
    display: block;
    padding-block: 1.15rem;
    border-bottom: 1px solid var(--line);
  }

  .tiers tbody th,
  .tiers tbody td {
    display: block;
    width: auto;
    padding: 0;
    border: 0;
  }

  .tiers tbody th { padding-bottom: 0.4rem; }
}

@media (max-width: 400px) {
  .problem li { grid-template-columns: 1.5rem minmax(0, 1fr); gap: 0.75rem; }

  .btn { width: 100%; justify-content: space-between; }
}

/* Motion preference ------------------------------------------------------ */

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

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }

  .btn:hover .btn__arrow,
  .card:hover .card__arrow { transform: none; }
}
/* Narrow diagram: larger type because the drawing is shown near 1:1 */
.loop__narrow .t-label { font-size: 15px; }
.loop__narrow .t-sub { font-size: 11px; }
.loop__narrow .t-scope { font-size: 10px; }