/* The public front page and its animated walk-through. */

:root,
[data-bs-theme="light"] {
  --film-bg: #e9f0fa;
  --film-glow: #ffffff;
  --film-grid: rgb(28 90 163 / 0.07);
  --film-edge: #cfdbec;
  --film-dot: #1c5aa3;
  --film-dim: #7ca1d3;
  --film-lit: #0a2e5c;
  --film-term: #0b7a84;
  --film-amber: #c26a0a;
  --film-amber-text: #8a4a05;
  --film-bar: #8fb0dc;
  --film-sheet: #ffffff;
  --film-sheet-edge: #c9d6e8;
  --film-text: #1b2330;
  --film-muted: #4c5768;
  --film-panel: rgb(255 255 255 / 0.92);
  --film-panel-edge: #d3deed;
  --film-ok: #1a7a4c;
  --film-shadow: 0 20px 48px -26px rgb(16 40 80 / 0.4);
}

[data-bs-theme="dark"] {
  --film-bg: #0a1120;
  --film-glow: #14294a;
  --film-grid: rgb(127 176 245 / 0.06);
  --film-edge: #223049;
  --film-dot: #7fb0f5;
  --film-dim: #4f6f9f;
  --film-lit: #dbeaff;
  --film-term: #5fd4d0;
  --film-amber: #f6bb55;
  --film-amber-text: #f6bb55;
  --film-bar: #4d6e9f;
  --film-sheet: #121d30;
  --film-sheet-edge: #2a3b57;
  --film-text: #eef2f7;
  --film-muted: #b3bdcb;
  --film-panel: rgb(14 22 36 / 0.88);
  --film-panel-edge: #2b3a54;
  --film-ok: #6fd3a2;
  --film-shadow: 0 28px 60px -30px rgb(0 0 0 / 0.85);
}

.landing {
  scroll-behavior: smooth;
}

/* Top bar and hero */

.landing-nav {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  height: 3.5rem;
  padding: 0 clamp(0.75rem, 2vw, 1.75rem);
}

.landing-nav-links {
  display: flex;
  gap: 1.25rem;
  margin-right: auto;
  margin-left: 1rem;
}

.landing-nav-links a {
  color: var(--app-muted);
  text-decoration: none;
}

.landing-nav-links a:hover {
  color: var(--app-text);
}

.landing-nav-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-left: auto;
}

.landing-hero {
  display: grid;
  grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr);
  gap: clamp(1rem, 4vw, 3.5rem);
  align-items: end;
  max-width: 1480px;
  margin: 0 auto;
  padding: 0.75rem clamp(0.75rem, 2vw, 1.75rem) 1.25rem;
}

.landing-eyebrow {
  margin: 0 0 0.5rem;
  color: var(--app-accent);
  font-size: 0.9rem;
  font-weight: 600;
}

.landing-title {
  margin: 0;
  font-size: clamp(2rem, 3.4vw, 3.125rem);
  font-weight: 700;
  line-height: 1.08;
  letter-spacing: -0.03em;
  text-wrap: balance;
}

/* The same mark the film leaves on the real page. */
.landing-title mark {
  padding: 0 0.04em;
  color: inherit;
  background: linear-gradient(var(--film-amber), var(--film-amber)) no-repeat 0 86% / 100% 0.085em;
  animation: landing-mark 1s 0.5s cubic-bezier(0.2, 0.7, 0.2, 1) backwards;
}

@keyframes landing-mark {
  from {
    background-size: 0% 0.085em;
  }
}

.landing-lede {
  max-width: 38rem;
  margin: 0 0 0.875rem;
  color: var(--app-muted);
  font-size: 1.0625rem;
  line-height: 1.45;
}

.landing-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.625rem;
  align-items: center;
}

.landing-stats {
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem 1.25rem;
  margin: 0.75rem 0 0;
  color: var(--app-muted);
  font-size: 0.875rem;
}

.landing-stats strong {
  color: var(--app-text);
  font-variant-numeric: tabular-nums;
}

/* The stage */

.film {
  max-width: 1480px;
  margin: 0 auto;
  padding: 0 clamp(0.75rem, 2vw, 1.75rem);
  scroll-margin-top: 0.75rem;
}

.film-stage {
  --film-top: 5.5rem;
  --film-bottom: 4.5rem;
  display: none;
  position: relative;
  height: clamp(30rem, calc(100svh - 17rem), 48rem);
  overflow: hidden;
  isolation: isolate;
  container-type: inline-size;
  color: var(--film-text);
  background: radial-gradient(ellipse 62% 72% at 62% 46%, var(--film-glow), var(--film-bg));
  border: 1px solid var(--film-edge);
  border-radius: 1.25rem;
}

.film-ready .film-stage {
  display: block;
}

.film-stage::before {
  position: absolute;
  z-index: -1;
  background-image:
    linear-gradient(var(--film-grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--film-grid) 1px, transparent 1px);
  background-size: 3rem 3rem;
  content: "";
  inset: 0;
  mask-image: radial-gradient(ellipse at 55% 50%, #000 30%, transparent 78%);
}

.film-canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

.film-canvas-top {
  z-index: 3;
  pointer-events: none;
}

.film-caption {
  position: absolute;
  z-index: 3;
  display: flex;
  gap: 0.875rem;
  align-items: baseline;
  height: var(--film-top);
  padding: 1rem 1.5rem 0;
  inset: 0 0 auto;
}

.film-caption-count {
  flex: none;
  padding: 0.125rem 0.625rem;
  color: var(--film-muted);
  font-size: 0.8125rem;
  font-variant-numeric: tabular-nums;
  border: 1px solid var(--film-edge);
  border-radius: 1rem;
}

.film-caption-title {
  flex: none;
  margin: 0;
  font-size: 1.25rem;
  font-weight: 650;
  letter-spacing: -0.01em;
}

.film-caption-text {
  margin: 0;
  max-width: 62rem;
  color: var(--film-muted);
  font-size: 0.975rem;
  line-height: 1.35;
}

.film-scene {
  position: absolute;
  z-index: 2;
  top: var(--film-top);
  right: 0;
  bottom: var(--film-bottom);
  left: 0;
  font-size: clamp(0.8125rem, 1.2cqi, 1.0625rem);
}

/* Panels start hidden. The film reveals them, so nothing flashes before it runs. */
.film-ask,
.film-search,
.film-chat,
.film-viewer,
.film-cursor {
  position: absolute;
  visibility: hidden;
  opacity: 0;
}

.film-sources li {
  visibility: hidden;
  opacity: 0;
}

.film-panel {
  background: var(--film-panel);
  border: 1px solid var(--film-panel-edge);
  border-radius: 0.875rem;
  box-shadow: var(--film-shadow);
  backdrop-filter: blur(14px);
}

/* Ask */

.film-ask {
  top: 3%;
  left: 4.5%;
  width: 44%;
  padding: 1.125rem 1.25rem;
}

.film-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.375rem;
  margin-bottom: 0.625rem;
}

.film-tag {
  display: inline-flex;
  gap: 0.3125rem;
  align-items: center;
  padding: 0.125rem 0.625rem;
  color: var(--film-muted);
  font-size: 0.8125rem;
  background: color-mix(in srgb, var(--film-dot) 14%, transparent);
  border-radius: 1rem;
}

.film-question {
  margin: 0;
  font-size: 1.42em;
  font-weight: 600;
  line-height: 1.25;
  letter-spacing: -0.012em;
}

.film-question mark {
  padding: 0;
  color: inherit;
  background: transparent;
  border-radius: 0.2em;
  transition: background-color 0.4s, color 0.4s;
}

.film-question mark.is-on {
  color: var(--film-lit);
  background: color-mix(in srgb, var(--film-term) 26%, transparent);
}

.film-question .is-hidden {
  visibility: hidden;
}

.film-question .is-caret {
  box-shadow: 2px 0 0 currentColor;
}

.film-plan {
  display: grid;
  gap: 0.25rem;
  margin: 0.875rem 0 0;
}

.film-plan div {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.3125rem 0;
  border-top: 1px solid var(--film-panel-edge);
}

.film-plan dt {
  color: var(--film-muted);
  font-weight: 400;
}

.film-plan dd {
  margin: 0;
  font-weight: 600;
}

/* Search */

.film-search {
  top: 6%;
  left: 4.5%;
  display: grid;
  gap: 0.75rem;
  width: 28%;
}

.film-read {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: center;
  padding: 0.75rem 1rem;
  background: var(--film-panel);
  border: 1px solid var(--film-panel-edge);
  border-radius: 0.75rem;
  backdrop-filter: blur(12px);
}

.film-read-name {
  display: inline-flex;
  gap: 0.4375rem;
  align-items: center;
  font-weight: 600;
}

.film-read-count {
  color: var(--film-lit);
  font-size: 1.5em;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
}

.film-read-term .film-read-count {
  color: var(--film-term);
}

.film-pills {
  display: flex;
  flex-wrap: wrap;
  grid-column: 1 / -1;
  gap: 0.3125rem;
  margin-top: 0.375rem;
}

.film-pills code {
  padding: 0.0625rem 0.4375rem;
  color: var(--film-term);
  font-size: 0.85em;
  background: color-mix(in srgb, var(--film-term) 14%, transparent);
  border-radius: 0.3125rem;
}

/* Sources */

.film-sources {
  position: absolute;
  top: 0;
  right: 4%;
  bottom: 0;
  display: grid;
  grid-auto-rows: 1fr;
  gap: 0.4375rem;
  width: 38%;
  margin: 0;
  padding: 0;
  list-style: none;
}

.film-sources li {
  display: flex;
  gap: 0.75rem;
  align-items: center;
  padding: 0.375rem 0.875rem;
  background: var(--film-panel);
  border: 1px solid var(--film-panel-edge);
  border-radius: 0.625rem;
  transition: border-color 0.3s, box-shadow 0.3s;
  backdrop-filter: blur(12px);
}

.film-sources li.is-cited {
  border-color: var(--film-amber);
  box-shadow: 0 0 0 1px var(--film-amber), 0 0 22px -6px var(--film-amber);
}

.film-sources strong {
  display: block;
  font-weight: 600;
}

.film-sources small {
  color: var(--film-muted);
  font-size: 0.875em;
}

.film-ref-num {
  flex: none;
  display: grid;
  width: 1.75em;
  height: 1.75em;
  place-items: center;
  color: var(--film-amber-text);
  font-weight: 700;
  background: color-mix(in srgb, var(--film-amber) 20%, transparent);
  border-radius: 0.4375em;
}

/* Answer */

.film-chat {
  top: 0;
  bottom: 0;
  left: 4.5%;
  display: flex;
  flex-direction: column;
  width: 51%;
  padding: 0.875rem 1.25rem;
  overflow: hidden;
}

.film-chat-q {
  align-self: flex-end;
  max-width: 88%;
  margin: 0 0 0.625rem;
  padding: 0.4375rem 0.875rem;
  background: color-mix(in srgb, var(--film-dot) 16%, transparent);
  border-radius: 0.875rem 0.875rem 0.25rem;
}

.film-steps {
  display: grid;
  gap: 0.375rem;
  margin: 0;
  padding-left: 1.375em;
  line-height: 1.38;
}

/* A step's number waits for its first word. */
.film-steps li::marker {
  color: transparent;
}

.film-steps li.is-started::marker {
  color: var(--film-muted);
}

.film-word,
.film-steps cite {
  opacity: 0;
  transition: opacity 0.18s linear;
}

.film-word.is-on,
.film-steps cite.is-on {
  opacity: 1;
}

.film-steps cite {
  display: inline-grid;
  min-width: 1.5em;
  height: 1.5em;
  margin-left: 0.125em;
  place-items: center;
  color: var(--film-amber-text);
  font-size: 0.82em;
  font-style: normal;
  font-weight: 700;
  vertical-align: 0.05em;
  background: color-mix(in srgb, var(--film-amber) 22%, transparent);
  border-radius: 0.375em;
  transition: opacity 0.18s linear, background-color 0.2s, color 0.2s;
}

.film-steps cite.is-pressed {
  color: #10161f;
  background: var(--film-amber);
}

[data-words][data-exact].is-exact {
  padding: 0 0.1875em;
  font-weight: 700;
  background: color-mix(in srgb, var(--film-amber) 30%, transparent);
  border-radius: 0.25em;
  transition: background-color 0.4s;
}

.film-notice {
  margin: auto 0 0;
  padding-top: 0.5rem;
  color: var(--film-muted);
  font-size: 0.9em;
  border-top: 1px solid var(--film-panel-edge);
}

/* Viewer */

.film-viewer {
  top: 0;
  right: 4%;
  bottom: 0;
  display: flex;
  flex-direction: column;
  width: 38%;
  overflow: hidden;
}

.film-viewer-bar {
  display: flex;
  flex: none;
  justify-content: space-between;
  align-items: center;
  padding: 0.4375rem 0.875rem;
  font-weight: 600;
  border-bottom: 1px solid var(--film-panel-edge);
}

.film-viewer-bar i {
  margin-right: 0.375rem;
}

.film-viewer-page {
  color: var(--film-amber-text);
  font-variant-numeric: tabular-nums;
}

.film-viewer-frame {
  position: relative;
  flex: 1;
  overflow: hidden;
  background: #2a3240;
}

.film-page {
  position: absolute;
  top: 0;
  left: 0;
  width: 594px;
  height: 774px;
  background: #fff;
  transform-origin: 0 0;
  will-change: transform;
}

.film-page img,
.film-page svg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

.film-mark {
  fill: #f6bb55;
  fill-opacity: 0.42;
}

.film-mark-exact {
  fill: none;
  stroke: #c26a0a;
  stroke-width: 1.4;
  opacity: 0;
}

/* Cursor */

.film-cursor {
  top: 0;
  left: 0;
  z-index: 5;
  filter: drop-shadow(0 2px 3px rgb(0 0 0 / 0.4));
}

.film-ripple {
  position: absolute;
  top: 3px;
  left: 3px;
  width: 44px;
  height: 44px;
  border: 2px solid var(--film-amber);
  border-radius: 50%;
  opacity: 0;
}

/* Controls */

.film-controls {
  position: absolute;
  z-index: 4;
  display: flex;
  gap: 1.125rem;
  align-items: center;
  height: var(--film-bottom);
  padding: 0 1.5rem;
  inset: auto 0 0;
}

.film-play {
  flex: none;
  display: grid;
  width: 2.75rem;
  height: 2.75rem;
  place-items: center;
  color: var(--film-text);
  font-size: 1.25rem;
  background: var(--film-panel);
  border: 1px solid var(--film-panel-edge);
  border-radius: 50%;
}

.film-play:hover {
  border-color: var(--film-amber);
}

.film-route {
  position: relative;
  flex: 1;
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  height: 2.75rem;
  cursor: grab;
  touch-action: none;
}

.film-route:active {
  cursor: grabbing;
}

.film-route-line {
  position: absolute;
  top: 0.8125rem;
  right: 0;
  left: 0;
  height: 2px;
  overflow: hidden;
  background: var(--film-edge);
}

.film-route-flown {
  height: 100%;
  background: var(--film-amber);
  transform: scaleX(0);
  transform-origin: 0 50%;
}

.film-plane {
  position: absolute;
  top: 0.0625rem;
  left: 0;
  z-index: 2;
  color: var(--film-amber);
  font-size: 1.1875rem;
  line-height: 1;
  pointer-events: none;
  transform: translateX(-50%) rotate(90deg);
}

.film-way {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  height: 2.75rem;
  padding: 0;
  color: var(--film-muted);
  font-size: 0.875rem;
  background: none;
  border: 0;
}

.film-way-mark {
  width: 0.625rem;
  height: 0.625rem;
  margin: 0.5625rem 0 0 -0.3125rem;
  background: var(--film-bg);
  border: 1.5px solid var(--film-muted);
  transform: rotate(45deg);
  transition: background-color 0.3s, border-color 0.3s;
}

.film-way-label {
  margin: 0.25rem 0 0 -0.3125rem;
}

.film-way.is-done .film-way-mark {
  background: var(--film-amber);
  border-color: var(--film-amber);
}

.film-way.is-current .film-way-label {
  color: var(--film-text);
  font-weight: 600;
}

.film-way:hover .film-way-label {
  color: var(--film-text);
}

.film-play:focus-visible,
.film-way:focus-visible {
  outline: 2px solid var(--app-accent);
  outline-offset: 2px;
}

.film-fineprint {
  display: none;
  margin: 0.625rem 0.25rem 0;
  color: var(--app-muted);
  font-size: 0.8125rem;
}

.film-ready .film-fineprint {
  display: block;
}

/* The steps in words: on show only if the animation can't run, always there for screen readers. */
.film-list {
  display: grid;
  gap: 0.75rem;
  margin: 1rem 0 0;
  padding-left: 1.5rem;
}

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

/* A short answer panel: the question was on screen moments ago, and the notice must not clip. */
@container (min-width: 821px) and (max-width: 1100px) {
  .film-chat-q {
    display: none;
  }
}

/* A narrow stage, such as a tablet held upright: panels stack over the canvas. */
@container (max-width: 820px) {
  .film-caption {
    flex-wrap: wrap;
    gap: 0.25rem 0.625rem;
    padding: 0.75rem 1rem 0;
  }

  .film-caption-text {
    flex-basis: 100%;
    font-size: 0.875rem;
  }

  .film-scene {
    top: 7.75rem;
    font-size: 0.875rem;
  }

  .film-ask {
    top: 0;
    right: 3%;
    left: 3%;
    width: auto;
    padding: 0.75rem 0.875rem;
  }

  .film-plan {
    display: none;
  }

  .film-search {
    top: 0;
    right: 3%;
    left: 3%;
    grid-template-columns: repeat(3, 1fr);
    width: auto;
  }

  .film-read {
    padding: 0.5rem 0.625rem;
  }

  .film-pills {
    display: none;
  }

  .film-sources {
    top: 56%;
    right: 3%;
    bottom: 0;
    grid-template-columns: repeat(2, 1fr);
    width: 94%;
  }

  .film-sources li {
    gap: 0.5rem;
    padding: 0.25rem 0.5rem;
  }

  .film-sources small {
    display: none;
  }

  .film-chat {
    right: 3%;
    left: 3%;
    width: auto;
  }

  .film-viewer {
    right: 3%;
    left: 3%;
    width: auto;
  }

  .film-controls {
    gap: 0.625rem;
    padding: 0 0.875rem;
  }

  .film-way-label {
    font-size: 0.75rem;
  }
}

/* Sections below the film */

.landing-section {
  max-width: 1480px;
  margin: 0 auto;
  padding: clamp(2.5rem, 6vw, 4.5rem) clamp(0.75rem, 2vw, 1.75rem) 0;
  scroll-margin-top: 0.5rem;
}

.landing-heading {
  margin: 0;
  font-size: clamp(1.75rem, 3vw, 2.5rem);
  font-weight: 700;
  letter-spacing: -0.025em;
}

.landing-subheading {
  max-width: 44rem;
  margin: 0.5rem 0 0;
  color: var(--app-muted);
  font-size: 1.0625rem;
}

.landing-rules,
.landing-roles {
  display: grid;
  gap: 1rem;
  margin: 1.75rem 0 0;
  padding: 0;
  list-style: none;
}

.landing-rules {
  grid-template-columns: repeat(auto-fit, minmax(15rem, 1fr));
}

.landing-roles {
  grid-template-columns: repeat(auto-fit, minmax(17rem, 1fr));
}

.landing-rules li,
.landing-roles li {
  padding: 1.25rem;
  background: var(--app-surface);
  border: 1px solid var(--app-border);
  border-radius: 0.875rem;
}

.landing-rules i {
  color: var(--app-accent);
  font-size: 1.375rem;
}

.landing-rules h3,
.landing-roles h3 {
  margin: 0.5rem 0 0.375rem;
  font-size: 1.0625rem;
  font-weight: 650;
}

.landing-rules p,
.landing-roles p {
  margin: 0;
  color: var(--app-muted);
}

.landing-mode {
  display: inline-flex;
  gap: 0.375rem;
  align-items: center;
  padding: 0.125rem 0.625rem;
  color: var(--app-accent);
  font-size: 0.8125rem;
  font-weight: 600;
  background: var(--app-accent-soft);
  border-radius: 1rem;
}

.landing-footer {
  max-width: 1480px;
  margin: 0 auto;
  padding: clamp(2.5rem, 6vw, 4.5rem) clamp(0.75rem, 2vw, 1.75rem) 2rem;
}

.landing-notice {
  display: flex;
  gap: 0.625rem;
  align-items: baseline;
  margin: 0;
  padding: 0.875rem 1rem;
  color: var(--app-warn);
  background: var(--app-warn-soft);
  border-radius: 0.625rem;
}

.landing-footer-line {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 0.5rem;
  margin: 1rem 0 0;
  color: var(--app-muted);
  font-size: 0.875rem;
}

@media (max-width: 900px) {
  .landing-hero {
    grid-template-columns: minmax(0, 1fr);
    gap: 0.75rem;
  }

  .film-stage {
    height: clamp(32rem, 76svh, 44rem);
  }

  .landing-nav-links {
    display: none;
  }
}

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

  .landing-title mark {
    animation: none;
  }

  .film-word,
  .film-steps cite,
  .film-question mark,
  .film-sources li,
  .film-way-mark {
    transition: none;
  }
}