/* Knowledge Hub marketing site
   Palette aligned with Thoughtlane (thoughtlane.com): near-black + lime CTAs. */

:root {
  --ink: #111111;
  --ink-2: #1a1a1a;
  --mist: #f0f0f0;
  --mist-2: #f8f8f8;
  --paper: #ffffff;
  --line: rgba(17, 17, 17, 0.1);
  --line-strong: rgba(17, 17, 17, 0.18);
  --muted: #7c7c7c;
  --text: #111111;
  --lime: #def59d;
  --lime-deep: #c8e66a;
  --olive: #4a5f14;
  --olive-deep: #3a4c10;
  --on-fill: #111111;
  --glow: rgba(222, 245, 157, 0.45);
  /* aliases kept so existing rules keep working */
  --celadon: var(--lime);
  --celadon-deep: var(--lime-deep);
  --font-display: "Fraunces", "Times New Roman", serif;
  --font-body: "Outfit", "Segoe UI", sans-serif;
  --radius: 1.25rem;
  --max: 1120px;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 1.05rem;
  line-height: 1.55;
  color: var(--text);
  background:
    radial-gradient(1100px 520px at 88% -8%, rgba(222, 245, 157, 0.35), transparent 55%),
    radial-gradient(800px 420px at -8% 18%, rgba(17, 17, 17, 0.04), transparent 50%),
    linear-gradient(180deg, var(--mist-2) 0%, var(--paper) 48%, var(--mist) 100%);
  min-height: 100%;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  opacity: 0.22;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='160' height='160'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='160' height='160' filter='url(%23n)' opacity='0.45'/%3E%3C/svg%3E");
  mix-blend-mode: multiply;
  z-index: 0;
}

.skip {
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--ink);
  color: var(--celadon);
  padding: 0.75rem 1rem;
  z-index: 100;
}
.skip:focus {
  left: 1rem;
  top: 1rem;
}

/* --- Top bar --- */
.top {
  position: sticky;
  top: 0;
  z-index: 40;
  display: flex;
  align-items: center;
  gap: 1.5rem;
  padding: 0.85rem clamp(1rem, 4vw, 2.5rem);
  backdrop-filter: blur(14px);
  background: color-mix(in srgb, var(--mist-2) 82%, transparent);
  border-bottom: 1px solid var(--line);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.65rem;
  text-decoration: none;
  color: var(--ink);
  font-weight: 600;
  letter-spacing: -0.02em;
}

.brand-mark {
  width: 1.35rem;
  height: 1.35rem;
  border-radius: 0.35rem;
  background:
    linear-gradient(135deg, var(--lime) 0%, var(--lime-deep) 60%, var(--olive) 100%);
  box-shadow: 0 0 0 1px rgba(17, 17, 17, 0.12);
}

.brand-name {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 600;
}

.top-nav {
  display: none;
  gap: 1.25rem;
  margin-left: 0.5rem;
}
.top-nav a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 500;
}
.top-nav a:hover {
  color: var(--ink);
}

.top-actions {
  display: none;
  margin-left: auto;
  align-items: center;
  gap: 0.75rem;
}

.link-quiet {
  color: var(--muted);
  text-decoration: none;
  font-weight: 500;
  font-size: 0.95rem;
}
.link-quiet:hover {
  color: var(--ink);
}

.nav-toggle {
  margin-left: auto;
  width: 2.5rem;
  height: 2.5rem;
  border: 1px solid var(--line-strong);
  border-radius: 0.65rem;
  background: var(--paper);
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  cursor: pointer;
}
.nav-toggle span {
  display: block;
  width: 1rem;
  height: 2px;
  background: var(--ink);
  border-radius: 1px;
}

.mobile-nav {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  padding: 0.75rem 1rem 1.25rem;
  background: var(--paper);
  border-bottom: 1px solid var(--line);
  position: relative;
  z-index: 39;
}
.mobile-nav[hidden] {
  display: none !important;
}
.mobile-nav a {
  padding: 0.75rem 0.5rem;
  color: var(--ink);
  text-decoration: none;
  font-weight: 500;
  border-bottom: 1px solid var(--line);
}

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  padding: 0.65rem 1.15rem;
  border-radius: 999px;
  font-family: var(--font-body);
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 0.25s var(--ease), background 0.2s ease, box-shadow 0.25s ease;
}
.btn:hover {
  transform: translateY(-1px);
}
.btn-fill {
  background: var(--celadon);
  color: var(--on-fill);
  box-shadow: 0 8px 24px var(--glow);
}
.btn-fill:hover {
  background: var(--celadon-deep);
}
.btn-ghost {
  background: transparent;
  color: var(--ink);
  border-color: var(--line-strong);
}
.btn-ghost:hover {
  background: rgba(17, 17, 17, 0.04);
}
.btn-lg {
  padding: 0.85rem 1.45rem;
  font-size: 1.02rem;
}

/* --- Hero --- */
.hero {
  position: relative;
  z-index: 1;
  display: grid;
  min-height: calc(100svh - 4rem);
  align-items: end;
  overflow: clip;
}

.hero-copy {
  position: relative;
  z-index: 2;
  padding: clamp(2rem, 6vh, 4rem) clamp(1.25rem, 5vw, 3.5rem) 2rem;
  max-width: 40rem;
}

.hero-brand {
  margin: 0 0 0.85rem;
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 4vw, 2.35rem);
  font-weight: 600;
  letter-spacing: -0.03em;
  color: var(--ink);
  animation: rise 0.9s var(--ease) both;
}

.hero-title {
  margin: 0 0 1rem;
  font-family: var(--font-display);
  font-size: clamp(2.1rem, 5.5vw, 3.35rem);
  font-weight: 600;
  line-height: 1.12;
  letter-spacing: -0.035em;
  color: var(--ink);
  animation: rise 0.9s var(--ease) 0.08s both;
}

.hero-lede {
  margin: 0 0 1.75rem;
  color: var(--muted);
  font-size: 1.08rem;
  max-width: 34rem;
  animation: rise 0.9s var(--ease) 0.14s both;
}

.hero-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  animation: rise 0.9s var(--ease) 0.2s both;
}

.hero-visual {
  position: absolute;
  inset: 0;
  z-index: 1;
  pointer-events: none;
}

.product-stage {
  position: absolute;
  right: -4%;
  bottom: 0;
  width: min(62vw, 720px);
  height: min(78vh, 640px);
  border-radius: var(--radius) var(--radius) 0 0;
  background: linear-gradient(165deg, var(--ink) 0%, var(--ink-2) 55%, #242424 100%);
  box-shadow:
    -40px 0 80px rgba(17, 17, 17, 0.16),
    inset 0 1px 0 rgba(222, 245, 157, 0.14);
  overflow: hidden;
  transform: translateX(8%) translateY(6%);
  animation: stage-in 1.15s var(--ease) 0.15s both;
}

.product-stage::before {
  content: "";
  position: absolute;
  inset: -20%;
  background:
    radial-gradient(circle at 70% 20%, rgba(222, 245, 157, 0.22), transparent 40%),
    radial-gradient(circle at 20% 80%, rgba(255, 255, 255, 0.06), transparent 45%);
  animation: drift 14s ease-in-out infinite alternate;
}

.product-chrome {
  position: relative;
  display: flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.85rem 1.1rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  color: rgba(248, 248, 248, 0.7);
  font-size: 0.8rem;
}
.product-chrome span {
  width: 0.5rem;
  height: 0.5rem;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.2);
}
.product-chrome span:first-child {
  background: #ff7b72;
}
.product-chrome span:nth-child(2) {
  background: #f2cc60;
}
.product-chrome span:nth-child(3) {
  background: #61c27b;
}
.product-chrome p {
  margin: 0 0 0 auto;
}

.product-body {
  position: relative;
  display: grid;
  grid-template-columns: 1.05fr 1fr;
  gap: 0.85rem;
  padding: 1rem;
  height: calc(100% - 2.8rem);
}

.product-lesson,
.product-qa {
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 0.85rem;
  padding: 1rem 1.1rem;
  color: #f8f8f8;
}

.product-kicker {
  margin: 0 0 0.5rem;
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--celadon);
  font-weight: 600;
}

.product-lesson p:last-child,
.product-qa .product-q {
  margin: 0;
  font-size: 0.92rem;
  line-height: 1.45;
  color: rgba(248, 248, 248, 0.88);
}

.product-q.is-live {
  position: relative;
  padding-left: 0.75rem;
}
.product-q.is-live::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.2rem;
  bottom: 0.2rem;
  width: 3px;
  border-radius: 2px;
  background: var(--celadon);
  animation: pulse-bar 2.2s ease-in-out infinite;
}

.product-answer {
  margin-top: 0.85rem;
  padding: 0.75rem;
  border-radius: 0.55rem;
  background: rgba(0, 0, 0, 0.25);
  font-size: 0.86rem;
  color: rgba(248, 248, 248, 0.78);
  min-height: 4.5rem;
}

.cursor {
  display: inline-block;
  width: 2px;
  height: 1em;
  background: var(--celadon);
  vertical-align: text-bottom;
  margin-right: 2px;
  animation: blink 1s steps(1) infinite;
}

.product-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 0.75rem;
  font-size: 0.72rem;
  color: rgba(248, 248, 248, 0.5);
}
.pill {
  padding: 0.35rem 0.7rem;
  border-radius: 999px;
  background: var(--celadon);
  color: var(--on-fill);
  font-weight: 600;
}

/* --- Strip --- */
.strip {
  position: relative;
  z-index: 2;
  display: grid;
  gap: 0.75rem;
  padding: 1.35rem clamp(1.25rem, 5vw, 3.5rem);
  background: var(--ink);
  color: rgba(248, 248, 248, 0.82);
  border-block: 1px solid rgba(222, 245, 157, 0.15);
}
.strip p {
  margin: 0;
  font-size: 0.95rem;
}
.strip strong {
  color: var(--celadon);
  font-weight: 600;
}

/* --- Sections --- */
.section {
  position: relative;
  z-index: 1;
  padding: clamp(3.5rem, 9vh, 6rem) clamp(1.25rem, 5vw, 3.5rem);
  max-width: var(--max);
  margin: 0 auto;
}

.section-head {
  max-width: 38rem;
  margin-bottom: 2.5rem;
}
.section-head h2,
.section-split h2,
.section-end h2 {
  margin: 0 0 0.75rem;
  font-family: var(--font-display);
  font-size: clamp(1.85rem, 3.8vw, 2.6rem);
  font-weight: 600;
  letter-spacing: -0.03em;
  line-height: 1.15;
}
.section-head p,
.section-split p,
.section-end > p {
  margin: 0;
  color: var(--muted);
  font-size: 1.05rem;
}

.steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1.75rem;
}
.steps li {
  padding-top: 1.25rem;
  border-top: 1px solid var(--line-strong);
}
.step-num {
  display: block;
  font-family: var(--font-display);
  font-size: 0.95rem;
  color: var(--olive);
  margin-bottom: 0.4rem;
  letter-spacing: 0.04em;
}
.steps h3 {
  margin: 0 0 0.4rem;
  font-size: 1.25rem;
  letter-spacing: -0.02em;
}
.steps p {
  margin: 0;
  color: var(--muted);
  max-width: 36rem;
}

/* Teacher split */
.section-split {
  display: grid;
  gap: 2.5rem;
  align-items: center;
}
.check-list {
  margin: 1.25rem 0 1.75rem;
  padding: 0;
  list-style: none;
}
.check-list li {
  position: relative;
  padding: 0.45rem 0 0.45rem 1.5rem;
  color: var(--text);
}
.check-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.85rem;
  width: 0.55rem;
  height: 0.55rem;
  border-radius: 50%;
  background: var(--celadon-deep);
  box-shadow: 0 0 0 3px rgba(200, 230, 106, 0.25);
}

.teacher-board {
  background: var(--ink);
  color: #f8f8f8;
  border-radius: var(--radius);
  padding: 1.25rem;
  display: grid;
  gap: 0.65rem;
  box-shadow: 0 24px 60px rgba(17, 17, 17, 0.22);
}
.board-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  padding: 0.85rem 1rem;
  border-radius: 0.75rem;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.07);
  font-size: 0.92rem;
}
.board-row.is-focus {
  border-color: rgba(222, 245, 157, 0.45);
  background: rgba(222, 245, 157, 0.08);
}
.tag {
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.3rem 0.55rem;
  border-radius: 999px;
}
.tag.wait {
  background: rgba(255, 255, 255, 0.08);
  color: rgba(248, 248, 248, 0.7);
}
.tag.ok {
  background: var(--celadon);
  color: var(--on-fill);
}
.tag.edit {
  background: rgba(242, 204, 96, 0.2);
  color: #f2cc60;
}
.board-graph {
  margin-top: 0.5rem;
  padding: 0.75rem 0.5rem 0.25rem;
}
.board-graph svg {
  width: 100%;
  height: auto;
  display: block;
}
.graph-line {
  stroke: var(--celadon);
  stroke-dasharray: 320;
  stroke-dashoffset: 320;
}
.board-graph circle {
  fill: var(--celadon);
}
.board-graph p {
  margin: 0.35rem 0 0;
  font-size: 0.78rem;
  color: rgba(248, 248, 248, 0.55);
}
.reveal-in .graph-line {
  animation: draw 1.4s var(--ease) forwards;
}

/* Study */
.section-study {
  max-width: none;
  margin: 0;
  padding-inline: 0;
  background:
    linear-gradient(180deg, transparent, rgba(17, 17, 17, 0.03)),
    radial-gradient(800px 400px at 50% 0%, rgba(222, 245, 157, 0.2), transparent 60%);
  text-align: center;
}
.section-head-light {
  margin-inline: auto;
  padding-inline: clamp(1.25rem, 5vw, 3.5rem);
}
.section-head-light a {
  color: var(--olive);
}
.study-stage {
  margin: 0 auto 1.5rem;
  padding-inline: clamp(1.25rem, 5vw, 3.5rem);
  max-width: 560px;
}
.drop-mock {
  border: 2px dashed color-mix(in srgb, var(--ink) 25%, transparent);
  border-radius: var(--radius);
  padding: 2.5rem 1.5rem;
  background: color-mix(in srgb, var(--paper) 70%, white);
}
.drop-title {
  margin: 0;
  font-family: var(--font-display);
  font-size: 1.45rem;
  letter-spacing: -0.02em;
}
.drop-mock > p:nth-child(2) {
  margin: 0.35rem 0 1.25rem;
  color: var(--muted);
  font-size: 0.95rem;
}
.file-chip {
  display: inline-block;
  padding: 0.55rem 0.9rem;
  border-radius: 0.55rem;
  background: var(--ink);
  color: var(--celadon);
  font-size: 0.88rem;
  font-weight: 500;
  animation: chip-in 0.8s var(--ease) both;
}
.kh-quiz-mock {
  text-align: left;
}
.kh-quiz-mock .file-chip {
  display: block;
  width: fit-content;
  margin-top: 0.5rem;
}
.kh-quiz-mock .file-chip:nth-of-type(2) {
  animation-delay: 0.12s;
}
.kh-quiz-mock .file-chip:nth-of-type(3) {
  animation-delay: 0.22s;
}
.kh-quiz-mock .gen-bar {
  margin-left: 0;
}
.kh-practice-cta {
  justify-content: center;
  margin-top: 1.25rem;
  padding-inline: clamp(1.25rem, 5vw, 3.5rem);
  padding-bottom: 2rem;
}
.gen-bar {
  margin: 1.25rem auto 0.5rem;
  width: min(100%, 280px);
  height: 6px;
  border-radius: 999px;
  background: rgba(17, 17, 17, 0.1);
  overflow: hidden;
}
.gen-bar span {
  display: block;
  height: 100%;
  width: 42%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--celadon-deep), var(--celadon));
  animation: load 2.4s ease-in-out infinite;
}
.gen-label {
  margin: 0;
  font-size: 0.85rem;
  color: var(--muted);
}
.study-privacy {
  margin: 0 auto 1.5rem;
  max-width: 32rem;
  padding-inline: 1.25rem;
  color: var(--muted);
  font-size: 0.95rem;
}

/* Access */
.access-grid {
  display: grid;
  gap: 2rem;
  border-top: 1px solid var(--line-strong);
  padding-top: 1.75rem;
}
.access-grid h3 {
  margin: 0 0 0.4rem;
  font-size: 1.15rem;
  letter-spacing: -0.02em;
}
.access-grid p {
  margin: 0;
  color: var(--muted);
}

/* FAQ */
.faq {
  display: grid;
  gap: 0.5rem;
}
.faq details {
  border-bottom: 1px solid var(--line-strong);
  padding: 0.35rem 0 0.85rem;
}
.faq summary {
  cursor: pointer;
  list-style: none;
  font-weight: 600;
  font-size: 1.05rem;
  padding: 0.75rem 0;
  letter-spacing: -0.01em;
}
.faq summary::-webkit-details-marker {
  display: none;
}
.faq summary::after {
  content: "+";
  float: right;
  color: var(--olive);
  font-weight: 500;
}
.faq details[open] summary::after {
  content: "–";
}
.faq p {
  margin: 0 0 0.5rem;
  color: var(--muted);
  max-width: 40rem;
}

/* End CTA */
.section-end {
  text-align: center;
  max-width: 40rem;
}
.section-end .hero-brand {
  animation: none;
}
.section-end .hero-cta {
  justify-content: center;
  margin-top: 1.75rem;
  animation: none;
}

/* Footer */
.foot {
  position: relative;
  z-index: 1;
  padding: 2.5rem clamp(1.25rem, 5vw, 3.5rem) 3rem;
  border-top: 1px solid var(--line);
  display: grid;
  gap: 0.75rem;
  color: var(--muted);
  font-size: 0.92rem;
}
.foot-brand {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  color: var(--ink);
  font-family: var(--font-display);
  font-weight: 600;
}
.foot nav {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
}
.foot a {
  color: var(--muted);
  text-decoration: none;
}
.foot a:hover {
  color: var(--ink);
}

/* Reveal */
.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
}
.reveal.reveal-in {
  opacity: 1;
  transform: none;
}

/* Motion */
@keyframes rise {
  from {
    opacity: 0;
    transform: translateY(16px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}
@keyframes stage-in {
  from {
    opacity: 0;
    transform: translateX(14%) translateY(10%);
  }
  to {
    opacity: 1;
    transform: translateX(8%) translateY(6%);
  }
}
@keyframes drift {
  from {
    transform: translate(0, 0) scale(1);
  }
  to {
    transform: translate(-3%, 2%) scale(1.05);
  }
}
@keyframes blink {
  50% {
    opacity: 0;
  }
}
@keyframes pulse-bar {
  0%,
  100% {
    opacity: 0.55;
  }
  50% {
    opacity: 1;
  }
}
@keyframes load {
  0% {
    transform: translateX(-100%);
  }
  100% {
    transform: translateX(280%);
  }
}
@keyframes chip-in {
  from {
    opacity: 0;
    transform: translateY(8px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}
@keyframes draw {
  to {
    stroke-dashoffset: 0;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *,
  *::before,
  *::after {
    animation: none !important;
    transition: none !important;
  }
  .reveal {
    opacity: 1;
    transform: none;
  }
}

/* Desktop layout */
@media (min-width: 860px) {
  .top-nav,
  .top-actions {
    display: flex;
  }
  .nav-toggle {
    display: none;
  }
  .hero {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.05fr);
    align-items: center;
  }
  .hero-copy {
    padding-bottom: clamp(3rem, 8vh, 5rem);
  }
  .hero-visual {
    position: relative;
    min-height: calc(100svh - 4rem);
  }
  .product-stage {
    right: 0;
    left: auto;
    top: 8%;
    bottom: auto;
    width: min(100%, 680px);
    height: min(72vh, 560px);
    border-radius: var(--radius) 0 0 var(--radius);
    transform: translateX(0);
    animation-name: stage-in-desk;
  }
  @keyframes stage-in-desk {
    from {
      opacity: 0;
      transform: translateX(8%);
    }
    to {
      opacity: 1;
      transform: none;
    }
  }
  .strip {
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
  }
  .steps {
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
  }
  .steps li {
    border-top: none;
    padding-top: 0;
    border-left: 1px solid var(--line-strong);
    padding-left: 1.25rem;
  }
  .steps li:first-child {
    border-left: none;
    padding-left: 0;
  }
  .section-split {
    grid-template-columns: 1fr 1fr;
    gap: 3.5rem;
    max-width: var(--max);
  }
  .access-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 2.5rem;
  }
  .foot {
    grid-template-columns: 1fr auto;
    align-items: end;
  }
  .foot nav {
    grid-column: 2;
    grid-row: 1 / span 2;
    flex-direction: column;
    align-items: flex-end;
  }
}

@media (max-width: 859px) {
  .product-body {
    grid-template-columns: 1fr;
  }
  .product-lesson {
    display: none;
  }
  .product-stage {
    width: min(92vw, 420px);
    height: 46vh;
    right: 4%;
    opacity: 0.95;
  }
  .hero {
    min-height: auto;
    padding-bottom: 42vh;
  }
}