/* ============================================================
   Kilva — AI Systems Studio
   Palette: ink #101826 · paper #F5F5F1 · ember #E25822 · steel #4A5160
   Type: Bricolage Grotesque (display) / Instrument Sans (body) /
         IBM Plex Mono (labels)
   ============================================================ */

:root {
  color-scheme: light;

  --ink: #101826;
  --ink-2: #14304e;
  --paper: #f5f5f1;
  --ember: #e25822;
  --ember-soft: #f5c6ae;
  --steel: #4a5160;
  --line: #dcdad2;
  --line-dark: rgba(245, 245, 241, 0.16);
  --white: #f5f5f1;

  --font-display: "Bricolage Grotesque", system-ui, sans-serif;
  --font-body: "Instrument Sans", system-ui, sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, monospace;

  --space-1: 0.5rem;
  --space-2: 1rem;
  --space-3: 1.5rem;
  --space-4: 2rem;
  --space-5: 3rem;
  --space-6: 4.5rem;
  --space-7: 6.5rem;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  background: var(--paper);
  color: var(--ink);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -webkit-tap-highlight-color: transparent;
}

button,
a,
summary {
  touch-action: manipulation;
}

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

/* ---------- a11y ---------- */
.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--ember);
  color: var(--paper);
  padding: 0.6rem 1rem;
  font-weight: 600;
  z-index: 100;
}
.skip-link:focus {
  left: 0;
}

a:focus-visible,
button:focus-visible,
summary:focus-visible,
.btn:focus-visible {
  outline: 2px solid var(--ember);
  outline-offset: 3px;
}

/* ---------- layout ---------- */
.wrap {
  width: min(1080px, 92vw);
  margin-inline: auto;
}

/* ---------- header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(245, 245, 241, 0.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-block: 1rem;
}

.site-header.is-scrolled {
  box-shadow: 0 1px 0 rgba(16, 24, 38, 0.06);
}

.wordmark {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.35rem;
  letter-spacing: -0.02em;
  color: var(--ink);
  text-decoration: none;
}

.wordmark-dot {
  color: var(--ember);
}

.nav {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.nav a {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  text-decoration: none;
  color: var(--steel);
  transition: color 0.2s ease;
}

.nav a.is-active {
  color: var(--ink);
  font-weight: 500;
}

.nav a.is-active:not(.nav-cta)::after {
  content: "";
  display: block;
  height: 2px;
  background: var(--ember);
  margin-top: 2px;
  border-radius: 2px;
}

.nav-cta {
  color: var(--paper) !important;
  background: var(--ink);
  padding: 0.55rem 1.1rem;
  border-radius: 999px;
  transition: background 0.2s ease;
}

.nav-cta:hover {
  background: var(--ember);
  color: var(--paper) !important;
}

/* ---------- shared section furniture ---------- */
.fig-label {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ember);
  margin-bottom: var(--space-2);
}

.section-title {
  font-family: var(--font-display);
  font-weight: 650;
  font-size: clamp(1.7rem, 3.4vw, 2.6rem);
  letter-spacing: -0.02em;
  line-height: 1.15;
  margin-bottom: var(--space-4);
  text-wrap: balance;
}

.section {
  padding-block: var(--space-7);
  border-top: 1px solid var(--line);
}

/* ---------- hero ---------- */
.hero {
  padding-block: var(--space-6) var(--space-7);
}

.hero-title {
  font-family: var(--font-display);
  font-weight: 750;
  font-size: clamp(2.6rem, 7.2vw, 4.6rem);
  letter-spacing: -0.03em;
  line-height: 1.04;
  max-width: 16ch;
  text-wrap: balance;
}

.hero-title::after {
  content: "";
  display: inline-block;
  width: 0.28em;
  height: 0.28em;
  background: var(--ember);
  border-radius: 50%;
  margin-left: 0.12em;
  vertical-align: baseline;
}

.hero-sub {
  max-width: 54ch;
  font-size: clamp(1.05rem, 1.6vw, 1.2rem);
  color: var(--steel);
  margin-top: var(--space-3);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-top: var(--space-4);
}

.btn {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  text-decoration: none;
  padding: 0.8rem 1.5rem;
  border-radius: 999px;
  transition: transform 0.15s ease, background 0.2s ease, color 0.2s ease;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn-primary {
  background: var(--ember);
  color: var(--paper);
}

.btn-primary:hover {
  background: #c74a1a;
}

.btn-ghost {
  border: 1px solid var(--ink);
  color: var(--ink);
}

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

.btn-lg {
  font-size: 0.95rem;
  padding: 1rem 2rem;
}

/* ---------- signature: workflow rail ---------- */
.rail {
  margin-top: var(--space-6);
  border: 1px solid var(--line);
  border-radius: 12px;
  background:
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 44px 44px;
  overflow: hidden;
}

.rail-svg {
  display: block;
  width: 100%;
  height: auto;
}

.rail-svg text {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.02em;
  fill: var(--ink);
}

.rail-node rect {
  fill: var(--paper);
  stroke: var(--line);
  stroke-width: 1.5;
}

.rail-node-core rect {
  fill: var(--ink);
  stroke: none;
}

.rail-node-core text {
  fill: var(--paper);
}

.rail-node-sub {
  fill: var(--steel) !important;
  font-size: 10.5px !important;
  letter-spacing: 0.05em !important;
}

.rail-node-core .rail-node-sub {
  fill: var(--ember-soft) !important;
}

.rail-lines {
  stroke: var(--steel);
  stroke-width: 1.5;
  opacity: 0.55;
}

.rail-labels {
  fill: var(--steel);
  font-size: 11px !important;
  letter-spacing: 0.14em !important;
  text-transform: uppercase;
}

.pulse {
  filter: drop-shadow(0 0 6px rgba(226, 88, 34, 0.8));
}

.pulse-a {
  offset-path: path("M 300 110 L 436 110");
  animation: pulse-a 3.2s ease-in-out infinite;
}

.pulse-b {
  offset-path: path("M 524 110 L 660 110");
  animation: pulse-b 3.2s ease-in-out infinite;
}

@keyframes pulse-a {
  0%, 30%  { offset-distance: 0%; }
  75%, 100% { offset-distance: 100%; }
}

@keyframes pulse-b {
  0%, 55%  { offset-distance: 0%; }
  100%     { offset-distance: 100%; }
}

/* ---------- cards ---------- */
.grid {
  display: grid;
  gap: var(--space-3);
}

.grid-3 {
  grid-template-columns: repeat(3, 1fr);
}

.grid-4 {
  grid-template-columns: repeat(4, 1fr);
}

.card {
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: var(--space-4);
  transition: border-color 0.2s ease, transform 0.2s ease;
}

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

.card-title {
  font-family: var(--font-display);
  font-weight: 650;
  font-size: 1.15rem;
  letter-spacing: -0.01em;
  margin-bottom: var(--space-1);
}

.card-body {
  color: var(--steel);
  font-size: 0.96rem;
}

/* dark section */
.section-dark {
  background: var(--ink);
  color: var(--paper);
  border-top: none;
}

.section-dark .fig-label {
  color: var(--ember-soft);
}

.section-dark .card {
  border-color: var(--line-dark);
  background: rgba(245, 245, 241, 0.03);
}

.section-dark .card:hover {
  border-color: var(--ember);
}

.section-dark .card-body {
  color: rgba(245, 245, 241, 0.72);
}

.card-index {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.14em;
  color: var(--ember);
  margin-bottom: var(--space-2);
}

.section-note {
  margin-top: var(--space-4);
  max-width: 60ch;
  font-size: 0.95rem;
  color: rgba(245, 245, 241, 0.72);
  border-left: 2px solid var(--ember);
  padding-left: var(--space-2);
}

/* ---------- process ---------- */
.steps {
  list-style: none;
  border-top: 1px solid var(--line);
}

.step {
  display: grid;
  grid-template-columns: 5rem 1fr;
  gap: var(--space-3);
  padding-block: var(--space-4);
  border-bottom: 1px solid var(--line);
}

.step-num {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  letter-spacing: 0.1em;
  color: var(--ember);
  padding-top: 0.25rem;
}

.step-title {
  font-family: var(--font-display);
  font-weight: 650;
  font-size: 1.25rem;
  letter-spacing: -0.01em;
  margin-bottom: var(--space-1);
}

.step-body {
  max-width: 58ch;
}

/* ---------- CTA ---------- */
.section-cta {
  border-top: none;
  background:
    radial-gradient(60% 120% at 85% 0%, rgba(226, 88, 34, 0.14), transparent 60%),
    var(--paper);
}

.cta-body {
  max-width: 48ch;
  color: var(--steel);
  font-size: 1.05rem;
  margin-bottom: var(--space-4);
}

/* ---------- footer ---------- */
.site-footer {
  border-top: 1px solid var(--line);
  padding-block: var(--space-4);
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.footer-note {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--steel);
}

/* ---------- reveal ---------- */
.reveal {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.reveal.is-visible {
  opacity: 1;
  transform: none;
}

/* ---------- responsive ---------- */
@media (max-width: 900px) {
  .grid-3,
  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }

  .rail {
    display: none;
  }
}

@media (max-width: 640px) {
  .section {
    padding-block: var(--space-5);
  }

  .hero {
    padding-block: var(--space-5);
  }

  .grid-3,
  .grid-4 {
    grid-template-columns: 1fr;
  }

  .step {
    grid-template-columns: 1fr;
    gap: var(--space-1);
  }

  .nav a:not(.nav-cta) {
    display: none;
  }

  .header-inner {
    padding-block: 0.85rem;
  }

  .footer-inner {
    flex-direction: column;
    gap: var(--space-2);
    align-items: flex-start;
  }
}

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

  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }

  .pulse-a,
  .pulse-b {
    animation: none;
  }
}

/* ============================================================
   Demos
   ============================================================ */

section[id] {
  scroll-margin-top: 90px;
}

.title-dim {
  display: block;
  font-size: 0.55em;
  font-weight: 400;
  color: var(--steel);
  margin-top: 0.4em;
  max-width: 34ch;
}

.demo {
  border: 1px solid var(--line);
  border-radius: 12px;
  background: #fbfbf8;
  overflow: hidden;
}

.card-cta {
  display: inline-block;
  margin-top: var(--space-2);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ember-soft);
  text-decoration: none;
  transition: color 0.2s ease;
}

.card-cta:hover {
  color: var(--ember);
  text-decoration: underline;
  text-underline-offset: 4px;
}

/* ---------- Demo A: Brief Machine ---------- */
.demo-a-chat {
  padding: var(--space-3) var(--space-4);
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  max-height: 560px;
  overflow-y: auto;
}

.msg {
  max-width: 78%;
  padding: 0.7rem 1rem;
  border-radius: 12px;
  font-size: 0.95rem;
  white-space: pre-line;
  animation: msg-in 0.25s ease both;
}

.msg-stream {
  display: block;
}

@keyframes msg-in {
  from {
    opacity: 0;
    transform: translateY(6px);
  }
}

.msg-machine {
  align-self: flex-start;
  background: var(--paper);
  border: 1px solid var(--line);
  color: var(--ink);
}

.msg-user {
  align-self: flex-end;
  background: var(--ink);
  color: var(--paper);
}

.msg-cursor::after {
  content: "▍";
  color: var(--ember);
  animation: blink 1s steps(2) infinite;
}

@keyframes blink {
  50% {
    opacity: 0;
  }
}

.prompts {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.prompt-chip {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.02em;
  color: var(--steel);
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.45rem 0.9rem;
  cursor: pointer;
  transition: border-color 0.2s ease, color 0.2s ease;
}

.prompt-chip:hover {
  border-color: var(--ember);
  color: var(--ember);
}

.demo-a-form {
  display: flex;
  gap: 0.75rem;
  padding: var(--space-3) var(--space-4);
  border-top: 1px solid var(--line);
  background: var(--paper);
}

.demo-a-form textarea {
  flex: 1;
  resize: vertical;
  font-family: var(--font-body);
  font-size: 0.95rem;
  color: var(--ink);
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 0.6rem 0.85rem;
}

.demo-a-form textarea:focus {
  outline: 2px solid var(--ember);
  outline-offset: 1px;
}

.brief-blueprint {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.35rem;
  margin-top: 0.6rem;
}

.brief-node {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.04em;
  color: var(--ink);
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.3rem 0.7rem;
}

.brief-node.is-core {
  background: var(--ember);
  border-color: var(--ember);
  color: var(--paper);
}

.brief-arrow {
  color: var(--ember);
  font-family: var(--font-mono);
  font-size: 0.7rem;
}

.brief-estimate {
  margin-top: 0.6rem;
}

.brief-estimate-label {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--steel);
}

.brief-bar {
  margin-top: 0.35rem;
  height: 8px;
  background: var(--line);
  border-radius: 99px;
  overflow: hidden;
}

.brief-bar-fill {
  display: block;
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, var(--ember), #f08652);
  border-radius: 99px;
  transition: width 0.8s ease;
}

.brief-pain {
  margin-top: 0.55rem;
  padding-left: 1rem;
  border-left: 2px solid var(--ember);
  font-size: 0.9rem;
  color: var(--steel);
}

/* ---------- Demo B: Inbox Machine ---------- */
.demo-b-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-4);
  background: var(--paper);
  border-bottom: 1px solid var(--line);
}

.b-stats {
  display: flex;
  gap: var(--space-3);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.06em;
  color: var(--steel);
  font-variant-numeric: tabular-nums;
}

.b-saved {
  color: var(--ember);
  font-weight: 500;
}

.demo-b-body {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr);
  min-height: 420px;
}

.b-inbox {
  list-style: none;
  border-right: 1px solid var(--line);
  overflow-y: auto;
  max-height: 460px;
}

.b-mail {
  padding: 0.85rem 1.1rem;
  border-bottom: 1px solid var(--line);
  cursor: default;
}

.b-mail-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.6rem;
}

.b-mail-from {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.04em;
  color: var(--steel);
}

.b-mail-subj {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 0.95rem;
  margin-top: 0.2rem;
}

.b-mail-snip {
  font-size: 0.83rem;
  color: var(--steel);
  margin-top: 0.15rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.b-mail.is-current {
  background: rgba(226, 88, 34, 0.06);
  border-left: 3px solid var(--ember);
}

.mail-status {
  flex-shrink: 0;
  font-family: var(--font-mono);
  font-size: 0.6rem;
  letter-spacing: 0.1em;
  padding: 0.2rem 0.5rem;
  border-radius: 999px;
  border: 1px solid var(--line);
  color: var(--steel);
}

.mail-status.is-replied {
  background: var(--ink);
  border-color: var(--ink);
  color: var(--paper);
}

.mail-status.is-escalated {
  background: var(--ember);
  border-color: var(--ember);
  color: var(--paper);
}

.mail-status.is-skipped {
  color: var(--steel);
  border-style: dashed;
}

.b-pane {
  display: flex;
  flex-direction: column;
  min-height: 420px;
}

.b-log {
  flex: 1;
  padding: var(--space-3) var(--space-4);
  font-family: var(--font-mono);
  font-size: 0.78rem;
  line-height: 1.9;
  overflow-y: auto;
  max-height: 300px;
  font-variant-numeric: tabular-nums;
}

.log-line {
  color: var(--steel);
  animation: msg-in 0.2s ease both;
}

.log-line .log-ts {
  color: var(--ember);
}

.log-line.is-action {
  color: var(--ink);
}

.b-reply {
  border-top: 1px solid var(--line);
  background: var(--paper);
  padding: var(--space-3) var(--space-4);
  font-size: 0.85rem;
  min-height: 120px;
}

.b-reply-empty {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--steel);
}

.b-reply-title {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ember);
  margin-bottom: 0.4rem;
}

.b-reply-body {
  color: var(--ink);
  white-space: pre-line;
}

/* ---------- Demo C: CSV Machine ---------- */
.c-pipeline {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  flex-wrap: wrap;
  padding: var(--space-3) var(--space-4);
  background: var(--paper);
  border-bottom: 1px solid var(--line);
}

.c-stage {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--steel);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.3rem 0.8rem;
  transition: background 0.3s ease, color 0.3s ease, border-color 0.3s ease;
}

.c-stage.is-active {
  background: var(--ember);
  border-color: var(--ember);
  color: var(--paper);
}

.c-stage.is-done {
  border-color: var(--ember);
  color: var(--ember);
}

.c-stage-arrow {
  color: var(--steel);
  font-family: var(--font-mono);
  font-size: 0.7rem;
}

.c-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.6fr);
  gap: 0;
}

.c-input {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-4);
  border-right: 1px solid var(--line);
}

.c-input textarea {
  flex: 1;
  resize: vertical;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  line-height: 1.6;
  color: var(--ink);
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 0.7rem 0.85rem;
}

.c-input textarea:focus {
  outline: 2px solid var(--ember);
  outline-offset: 1px;
}

.c-actions {
  display: flex;
  gap: 0.6rem;
}

.c-output {
  display: flex;
  flex-direction: column;
  padding: var(--space-3) var(--space-4);
}

.c-table-wrap {
  flex: 1;
  overflow: auto;
  max-height: 340px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--white);
}

.c-table-wrap table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.8rem;
}

.c-table-wrap th,
.c-table-wrap td {
  text-align: left;
  padding: 0.45rem 0.7rem;
  border-bottom: 1px solid var(--line);
  white-space: nowrap;
}

.c-table-wrap th {
  font-family: var(--font-mono);
  font-size: 0.66rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--steel);
  background: var(--paper);
  position: sticky;
  top: 0;
}

.c-table-wrap tr.is-fixed {
  background: rgba(226, 88, 34, 0.05);
}

.c-side {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
  margin-top: var(--space-2);
}

.c-log {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  line-height: 1.8;
  color: var(--steel);
  font-variant-numeric: tabular-nums;
}

.c-log .log-ts {
  color: var(--ember);
}

.c-empty {
  padding: var(--space-4);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--steel);
  text-align: center;
}

/* ---------- Demo D: Connector Board ---------- */
.demo-d {
  padding: var(--space-3) var(--space-4);
}

.d-board {
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--paper);
  overflow: hidden;
}

.d-svg {
  display: block;
  width: 100%;
  height: auto;
}

.d-lines line {
  stroke: var(--steel);
  stroke-width: 1.5;
  opacity: 0.45;
}

.d-node rect {
  fill: var(--white);
  stroke: var(--line);
  stroke-width: 1.5;
}

.d-node text {
  font-family: var(--font-mono);
  font-size: 14px;
  fill: var(--ink);
}

.d-sub {
  font-size: 10.5px !important;
  letter-spacing: 0.06em;
  fill: var(--steel) !important;
}

.d-hub rect {
  fill: var(--ink);
  stroke: none;
}

.d-hub text {
  fill: var(--paper);
}

.d-hub .d-sub {
  fill: var(--ember-soft) !important;
}

.pulse-d {
  filter: drop-shadow(0 0 6px rgba(226, 88, 34, 0.8));
}

.d-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: var(--space-2);
}

.event-chip {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--ink);
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.5rem 1rem;
  cursor: pointer;
  transition: border-color 0.2s ease, color 0.2s ease;
}

.event-chip:hover:not(:disabled) {
  border-color: var(--ember);
  color: var(--ember);
}

.event-chip:disabled {
  opacity: 0.45;
  cursor: wait;
}

.d-log {
  margin-top: var(--space-2);
  font-family: var(--font-mono);
  font-size: 0.76rem;
  line-height: 1.9;
  color: var(--steel);
  min-height: 2.5rem;
  font-variant-numeric: tabular-nums;
}

.d-log .log-ts {
  color: var(--ember);
}

/* ---------- FAQ ---------- */
.faq {
  border-top: 1px solid var(--line);
}

.faq-item {
  border-bottom: 1px solid var(--line);
}

.faq-item summary {
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.1rem;
  letter-spacing: -0.01em;
  padding-block: 1.1rem;
  color: var(--ink);
  transition: color 0.2s ease;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::after {
  content: "+";
  font-family: var(--font-mono);
  font-size: 1.1rem;
  color: var(--ember);
  transition: transform 0.2s ease;
}

.faq-item[open] summary::after {
  transform: rotate(45deg);
}

.faq-item summary:hover {
  color: var(--ember);
}

.faq-item[open] summary {
  color: var(--ink);
}

.faq-body {
  max-width: 62ch;
  color: var(--steel);
  font-size: 0.95rem;
  padding: 0 0 1.2rem 0;
  margin-top: -0.4rem;
}

/* ---------- demo responsive ---------- */
@media (max-width: 900px) {
  .demo-b-body,
  .c-body {
    grid-template-columns: 1fr;
  }

  .b-inbox {
    border-right: none;
    border-bottom: 1px solid var(--line);
    max-height: 260px;
  }
}

@media (max-width: 640px) {
  .demo-a-chat {
    padding: var(--space-2) var(--space-3);
  }

  .demo-a-form,
  .demo-b-top,
  .c-input,
  .c-output {
    padding-left: var(--space-3);
    padding-right: var(--space-3);
  }

  .msg {
    max-width: 92%;
  }

  .c-actions {
    flex-wrap: wrap;
  }

  .b-stats {
    flex-direction: column;
    gap: 0.2rem;
  }
}

/* ---------- Calculator ---------- */
.calc-box {
  padding: var(--space-4);
}

.calc-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr);
  gap: var(--space-5);
  align-items: center;
}

.calc-inputs {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.calc-field {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.calc-label-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  font-size: 0.95rem;
}

.calc-label-row label {
  font-weight: 500;
  color: var(--ink);
}

.calc-val {
  font-size: 0.85rem;
  color: var(--ember);
  font-variant-numeric: tabular-nums;
  font-weight: 500;
}

.calc-field input[type="range"] {
  accent-color: var(--ember);
  height: 6px;
  background: var(--line);
  border-radius: 4px;
  cursor: pointer;
}

.calc-outputs {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.calc-card {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 1rem 1.2rem;
}

.calc-card-highlight {
  background: var(--ink);
  color: var(--paper);
  border-color: var(--ink);
}

.calc-out-label {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--steel);
}

.calc-card-highlight .calc-out-label {
  color: var(--ember-soft);
}

.calc-out-val {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.6rem;
  letter-spacing: -0.02em;
  margin-top: 0.2rem;
  font-variant-numeric: tabular-nums;
}

.calc-ember {
  color: var(--ember);
}

.calc-unit {
  font-size: 0.9rem;
  font-weight: 400;
  color: var(--steel);
}

.calc-card-highlight .calc-unit {
  color: rgba(245, 245, 241, 0.7);
}

.btn-calc {
  margin-top: 1rem;
  display: inline-block;
  width: 100%;
  text-align: center;
}

/* ---------- Contact Actions ---------- */
.cta-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  align-items: center;
}

/* ---------- Demo C Action Group ---------- */
.c-out-actions {
  display: flex;
  gap: 0.5rem;
}

/* ---------- Demo D Interactive Nodes ---------- */
.d-clickable {
  cursor: pointer;
}

.d-clickable rect {
  transition: stroke 0.2s ease, fill 0.2s ease;
}

.d-clickable:hover rect {
  stroke: var(--ember);
  fill: #fff;
}

.d-clickable.is-active rect {
  stroke: var(--ember);
  fill: rgba(226, 88, 34, 0.08);
}

/* ---------- Custom Scrollbars ---------- */
.b-inbox::-webkit-scrollbar,
.b-log::-webkit-scrollbar,
.c-table-wrap::-webkit-scrollbar,
.demo-a-chat::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}

.b-inbox::-webkit-scrollbar-thumb,
.b-log::-webkit-scrollbar-thumb,
.c-table-wrap::-webkit-scrollbar-thumb,
.demo-a-chat::-webkit-scrollbar-thumb {
  background: var(--line);
  border-radius: 4px;
}

.b-inbox::-webkit-scrollbar-thumb:hover,
.b-log::-webkit-scrollbar-thumb:hover,
.c-table-wrap::-webkit-scrollbar-thumb:hover,
.demo-a-chat::-webkit-scrollbar-thumb:hover {
  background: var(--steel);
}

@media (max-width: 900px) {
  .calc-grid {
    grid-template-columns: 1fr;
  }
}

/* ---------- motion preferences ---------- */
@media (prefers-reduced-motion: reduce) {
  .msg {
    animation: none;
  }

  .msg-cursor::after {
    animation: none;
  }

  .brief-bar-fill {
    transition: none;
  }
}