/* Kairen public website — layout and components
   Grammar: one reader question -> one decision spine -> explicit source/state/gate
            -> restrained focal signal -> accessible evidence rail */

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

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

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

body {
  margin: 0;
  background: var(--surface-base);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: var(--step-0);
  line-height: 1.65;
  letter-spacing: -0.011em;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
  word-break: keep-all;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: inherit;
}

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

.k-skip {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 100;
  background: var(--action-bg);
  color: var(--action-fg);
  padding: 12px 20px;
  font-size: var(--step--1);
}

.k-skip:focus {
  left: 12px;
  top: 12px;
}

/* ---------- layout primitives ---------- */

.k-shell {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--pad-x);
}

.k-shell--wide {
  max-width: var(--container-wide);
}

.k-section {
  background: var(--surface-base);
  color: var(--text-primary);
  padding-block: var(--section-y);
  border-top: 1px solid var(--line-decorative);
}

.k-section--tight {
  padding-block: var(--section-y-sm);
}

.k-eyebrow {
  font-family: var(--font-mono);
  font-size: 11px;
  line-height: 1;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--text-tertiary);
  margin: 0 0 20px;
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.k-eyebrow::before {
  content: "";
  width: 24px;
  height: 1px;
  background: var(--signal);
  flex: none;
}

h1,
h2,
h3,
h4 {
  margin: 0;
  font-weight: 620;
  letter-spacing: -0.038em;
  line-height: 1.08;
  text-wrap: balance;
}

h1 {
  font-size: var(--step-5);
  letter-spacing: -0.052em;
}

h2 {
  font-size: var(--step-4);
  letter-spacing: -0.045em;
}

h3 {
  font-size: var(--step-2);
  letter-spacing: -0.03em;
  line-height: 1.22;
}

h4 {
  font-size: var(--step-1);
  letter-spacing: -0.022em;
  line-height: 1.3;
}

p {
  margin: 0;
}

.k-lede {
  font-size: var(--step-1);
  line-height: 1.6;
  color: var(--text-secondary);
  max-width: 38ch;
}

.k-body {
  color: var(--text-secondary);
  max-width: 62ch;
}

.k-stack > * + * {
  margin-top: var(--gap, 24px);
}

/* ---------- header ---------- */

.k-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background: color-mix(in srgb, var(--surface-base) 88%, transparent);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--line-decorative);
}

.k-header__inner {
  display: flex;
  align-items: center;
  gap: 24px;
  height: 72px;
}

.k-brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  flex: none;
}

.k-brand img {
  height: 20px;
  width: auto;
}

.k-nav {
  display: flex;
  align-items: center;
  gap: 4px;
  margin-inline-start: auto;
}

.k-nav a {
  text-decoration: none;
  font-size: var(--step--1);
  color: var(--text-tertiary);
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  transition: color var(--dur-fast) var(--ease-out);
  white-space: nowrap;
}

.k-nav a:hover {
  color: var(--text-primary);
}

.k-nav a[aria-current="page"]:not(.k-btn) {
  color: var(--text-primary);
  box-shadow: inset 0 -1px 0 var(--signal);
}

.k-header .k-btn {
  flex: none;
}

/* The primary entry lives outside the nav on desktop and inside it on mobile,
   so exactly one instance is visible at any width. */
@media (min-width: 901px) {
  .k-nav > .k-btn {
    display: none;
  }
}

.k-menu-toggle {
  display: none;
}

@media (max-width: 900px) {
  .k-header__inner {
    height: 64px;
    gap: 12px;
  }

  .k-menu-toggle {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    margin-inline-start: auto;
    background: none;
    border: 1px solid var(--line-structural);
    color: var(--text-primary);
    font: inherit;
    font-size: var(--step--1);
    padding: 8px 14px;
    border-radius: var(--radius-sm);
    cursor: pointer;
  }

  .k-nav {
    display: none;
    position: absolute;
    inset-inline: 0;
    top: 100%;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: var(--surface-raised);
    border-bottom: 1px solid var(--line-decorative);
    padding: 8px var(--pad-x) 20px;
  }

  .k-nav[data-open="true"] {
    display: flex;
  }

  .k-nav a {
    padding: 14px 0;
    font-size: var(--step-0);
    border-bottom: 1px solid var(--line-decorative);
    border-radius: 0;
  }

  .k-nav a[aria-current="page"] {
    box-shadow: none;
    color: var(--text-signal);
  }

  .k-nav .k-btn {
    margin-top: 16px;
    justify-content: center;
  }

  .k-header > .k-shell > .k-btn--primary {
    display: none;
  }
}

/* ---------- buttons ---------- */

.k-btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-height: 46px;
  padding: 0 22px;
  border-radius: var(--radius-sm);
  background: transparent;
  font-family: inherit;
  font-size: var(--step--1);
  font-weight: 560;
  letter-spacing: -0.01em;
  text-decoration: none;
  border: 1px solid transparent;
  cursor: pointer;
  transition: background var(--dur-fast) var(--ease-out),
    border-color var(--dur-fast) var(--ease-out), color var(--dur-fast) var(--ease-out);
}

.k-btn--primary {
  background: var(--action-bg);
  color: var(--action-fg);
}

.k-btn--primary:hover {
  background: var(--action-bg-hover);
}

.k-btn--secondary {
  border-color: var(--line-structural);
  color: var(--text-primary);
}

.k-btn--secondary:hover {
  border-color: var(--text-primary);
}

.k-btn__arrow {
  font-family: var(--font-mono);
  opacity: 0.7;
}

.k-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.k-textlink {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--text-signal);
  text-decoration: none;
  font-size: var(--step--1);
  font-weight: 540;
  border-bottom: 1px solid transparent;
  padding-bottom: 2px;
}

.k-textlink:hover {
  border-bottom-color: currentColor;
}

/* ---------- hero ---------- */

.k-hero {
  position: relative;
  background: var(--surface-base);
  padding-block: clamp(56px, 8vw, 104px) clamp(64px, 8vw, 120px);
  overflow: hidden;
}

.k-hero::after {
  /* Trace Cut — single restrained diagonal, decorative only */
  content: "";
  position: absolute;
  inset-block: -20%;
  inset-inline-start: 62%;
  width: 1px;
  background: linear-gradient(180deg, transparent, var(--line-decorative) 30%, transparent);
  transform: rotate(12deg);
  pointer-events: none;
}

.k-hero__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(40px, 5vw, 64px);
  align-items: start;
}

@media (min-width: 1000px) {
  .k-hero__grid {
    grid-template-columns: minmax(0, 47fr) minmax(0, 53fr);
    gap: clamp(40px, 4vw, 72px);
    align-items: center;
  }
}

.k-hero h1 {
  margin-bottom: 28px;
}

.k-hero__sub {
  color: var(--text-secondary);
  max-width: 46ch;
  margin-bottom: 32px;
}

.k-hero__note {
  margin-top: 24px;
  font-size: var(--step--1);
  color: var(--text-tertiary);
  max-width: 44ch;
}

/* ---------- console (static evidence surface) ---------- */

.k-console {
  border: 1px solid var(--line-decorative);
  border-radius: var(--radius-md);
  background: linear-gradient(180deg, var(--surface-panel), var(--surface-sunken));
  overflow: hidden;
  font-family: var(--font-mono);
  box-shadow: 0 40px 120px rgba(0, 0, 0, 0.38);
}

.k-console__bar {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  padding: 12px 16px;
  border-bottom: 1px solid var(--line-decorative);
  font-size: 10.5px;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  color: var(--text-tertiary);
}

.k-console__title {
  color: var(--text-secondary);
}

.k-stamp {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 8px;
  border: 1px solid var(--line-structural);
  border-radius: var(--radius-xs);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-tertiary);
  white-space: nowrap;
}

.k-stamp--signal {
  border-color: var(--signal-line);
  color: var(--text-signal);
}

.k-stamp::before {
  content: "";
  width: 5px;
  height: 5px;
  background: currentColor;
  flex: none;
}

.k-console__bar .k-stamp {
  margin-inline-start: auto;
}

.k-console__body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
}

@media (min-width: 620px) {
  .k-console__body {
    grid-template-columns: minmax(0, 1.55fr) minmax(0, 1fr);
  }
}

.k-console__spine {
  padding: 18px 16px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.k-step {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 12px;
  align-items: start;
  padding: 11px 12px;
  border: 1px solid var(--line-decorative);
  border-radius: var(--radius-sm);
  background: rgba(255, 255, 255, 0.015);
  transition: border-color var(--dur-base) var(--ease-out),
    background var(--dur-base) var(--ease-out);
}

.k-step__idx {
  font-size: 10px;
  letter-spacing: 0.1em;
  color: var(--text-tertiary);
  padding-top: 3px;
}

.k-step__name {
  font-size: 12.5px;
  letter-spacing: 0.02em;
  color: var(--text-secondary);
  line-height: 1.4;
}

.k-step__meta {
  font-size: 10.5px;
  color: var(--text-tertiary);
  margin-top: 4px;
  line-height: 1.45;
}

.k-step[data-state="active"] {
  border-color: var(--signal-line);
  background: var(--signal-soft);
}

.k-step[data-state="active"] .k-step__name {
  color: var(--text-primary);
}

.k-step[data-state="active"] .k-step__idx {
  color: var(--text-signal);
}

.k-step[data-state="active"]::after {
  content: "ACTIVE";
  grid-column: 2;
  font-size: 9.5px;
  letter-spacing: 0.14em;
  color: var(--text-signal);
}

.k-console__inspector {
  border-top: 1px solid var(--line-decorative);
  padding: 18px 16px;
  background: rgba(0, 0, 0, 0.22);
}

@media (min-width: 620px) {
  .k-console__inspector {
    border-top: 0;
    border-inline-start: 1px solid var(--line-decorative);
  }
}

.k-insp__label {
  font-size: 10px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--text-tertiary);
  margin-bottom: 14px;
}

.k-insp__row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 14px;
  padding: 9px 0;
  border-bottom: 1px solid var(--line-decorative);
  font-size: 11.5px;
}

.k-insp__row dt {
  color: var(--text-tertiary);
  letter-spacing: 0.06em;
  flex: none;
}

.k-insp__row dd {
  margin: 0;
  color: var(--text-secondary);
  text-align: end;
}

.k-insp__gate {
  margin-top: 16px;
  padding: 12px;
  border: 1px dashed var(--line-structural);
  border-radius: var(--radius-sm);
  font-size: 11px;
  line-height: 1.5;
  color: var(--text-secondary);
}

.k-insp__gate strong {
  display: block;
  color: var(--text-primary);
  font-size: 10.5px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-bottom: 6px;
}

.k-console__foot {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  padding: 11px 16px;
  border-top: 1px solid var(--line-decorative);
  font-size: 10.5px;
  color: var(--text-tertiary);
  letter-spacing: 0.04em;
}

.k-console__pause {
  margin-inline-start: auto;
  background: none;
  border: 1px solid var(--line-structural);
  color: var(--text-secondary);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  padding: 5px 10px;
  border-radius: var(--radius-xs);
  cursor: pointer;
}

.k-console__pause:hover {
  color: var(--text-primary);
  border-color: var(--text-primary);
}

/* ---------- decision spine strip ---------- */

.k-spine {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(148px, 1fr));
  border: 1px solid var(--line-decorative);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.k-spine__cell {
  padding: 20px 18px;
  border-inline-end: 1px solid var(--line-decorative);
  border-block-end: 1px solid var(--line-decorative);
}

.k-spine__n {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.14em;
  color: var(--text-tertiary);
  display: block;
  margin-bottom: 10px;
}

.k-spine__t {
  font-size: var(--step--1);
  font-weight: 560;
  letter-spacing: -0.015em;
  color: var(--text-primary);
}

.k-spine__d {
  font-size: 12.5px;
  color: var(--text-tertiary);
  margin-top: 6px;
  line-height: 1.5;
}

/* ---------- cards / grids ---------- */

.k-grid {
  display: grid;
  gap: var(--grid-gap);
}

.k-grid--2 {
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 300px), 1fr));
}

.k-grid--3 {
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 262px), 1fr));
}

.k-card {
  padding: clamp(22px, 2.4vw, 30px);
  border: 1px solid var(--line-decorative);
  border-radius: var(--radius-md);
  background: var(--surface-raised);
}

.k-card__n {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.14em;
  color: var(--text-tertiary);
  display: block;
  margin-bottom: 16px;
}

.k-card h3 {
  margin-bottom: 12px;
}

.k-card p {
  color: var(--text-secondary);
  font-size: var(--step--1);
  line-height: 1.62;
}

.k-split {
  display: grid;
  gap: clamp(32px, 5vw, 72px);
  align-items: start;
}

@media (min-width: 900px) {
  .k-split {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
  }

  .k-split--even {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

/* ---------- boundary table ---------- */

.k-tablewrap {
  overflow-x: auto;
  border: 1px solid var(--line-decorative);
  border-radius: var(--radius-md);
}

.k-table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--step--1);
  min-width: 520px;
}

.k-table th,
.k-table td {
  text-align: start;
  padding: 15px 18px;
  border-bottom: 1px solid var(--line-decorative);
  vertical-align: top;
  line-height: 1.55;
}

.k-table thead th {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--text-tertiary);
  font-weight: 400;
  background: var(--surface-sunken);
}

.k-table td:first-child {
  color: var(--text-primary);
}

.k-table td:last-child {
  color: var(--text-secondary);
}

.k-table tbody tr:last-child td {
  border-bottom: 0;
}

/* ---------- evidence rail ---------- */

.k-rail {
  border: 1px solid var(--line-structural);
  border-radius: var(--radius-md);
  padding: clamp(22px, 3vw, 32px);
  background: var(--surface-raised);
}

.k-rail__head {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 18px;
}

.k-rail dl {
  margin: 0;
  display: grid;
  gap: 0;
}

.k-rail__row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 4px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line-decorative);
}

@media (min-width: 640px) {
  .k-rail__row {
    grid-template-columns: 168px minmax(0, 1fr);
    gap: 20px;
    align-items: baseline;
  }
}

.k-rail__row:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.k-rail dt {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-tertiary);
}

.k-rail dd {
  margin: 0;
  color: var(--text-secondary);
  font-size: var(--step--1);
  line-height: 1.6;
}

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

.k-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.k-list > li {
  padding: 22px 0;
  border-bottom: 1px solid var(--line-decorative);
  display: grid;
  gap: 8px;
}

@media (min-width: 760px) {
  .k-list > li {
    grid-template-columns: 128px minmax(0, 1fr);
    gap: 32px;
    align-items: baseline;
  }
}

.k-list__k {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--text-tertiary);
}

.k-list__v {
  color: var(--text-secondary);
  max-width: 68ch;
}

.k-list__v strong {
  color: var(--text-primary);
  font-weight: 560;
  display: block;
  margin-bottom: 6px;
  letter-spacing: -0.015em;
}

/* ---------- CTA band ---------- */

.k-cta {
  border: 1px solid var(--line-structural);
  border-radius: var(--radius-md);
  padding: clamp(32px, 5vw, 64px);
  display: grid;
  gap: 28px;
  background: var(--surface-raised);
}

@media (min-width: 900px) {
  .k-cta {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
    gap: 48px;
  }
}

/* ---------- footer ---------- */

.k-footer {
  background: var(--surface-sunken);
  color: var(--text-primary);
  border-top: 1px solid var(--line-decorative);
  padding-block: clamp(48px, 6vw, 72px) 32px;
}

.k-footer__grid {
  display: grid;
  gap: 40px;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 190px), 1fr));
}

.k-footer h2 {
  font-size: var(--step--1);
  font-family: var(--font-mono);
  font-weight: 400;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--text-tertiary);
  margin-bottom: 16px;
}

.k-footer ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.k-footer a {
  text-decoration: none;
  font-size: var(--step--1);
  color: var(--text-secondary);
}

.k-footer a:hover {
  color: var(--text-primary);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.k-footer__brand img {
  height: 22px;
  margin-bottom: 16px;
}

.k-footer__note {
  color: var(--text-tertiary);
  font-size: 12.5px;
  line-height: 1.6;
  max-width: 34ch;
}

.k-footer__base {
  margin-top: 48px;
  padding-top: 24px;
  border-top: 1px solid var(--line-decorative);
  display: flex;
  flex-wrap: wrap;
  gap: 12px 24px;
  align-items: center;
  font-size: 12px;
  color: var(--text-tertiary);
}

.k-footer__base .k-stamp {
  margin-inline-start: auto;
}

/* ---------- page intro (inner pages) ---------- */

.k-pagehead {
  padding-block: clamp(56px, 7vw, 96px) clamp(40px, 5vw, 64px);
  border-bottom: 1px solid var(--line-decorative);
}

.k-pagehead h1 {
  font-size: var(--step-4);
  max-width: 22ch;
  margin-bottom: 24px;
}

/* ---------- motion ---------- */

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
}