/* Molecule: a chemistry lecture hall. Slate, chalk, and CPK colors for the atoms. */

@font-face {
  font-family: "Shantell Sans";
  src: url("assets/fonts/shantell-sans-latin.woff2") format("woff2");
  font-weight: 300 800;
  font-display: swap;
}

:root {
  --wall: #101617;
  --slate: #1c2526;
  --slate-hi: #263233;
  --chalk: #efece2;
  --chalk-dim: #b9bdb4;
  --yellow: #ffe45c; /* yellow chalk: anything you can act on, and every measurement */
  --wood: #7a5536;
  --wood-dark: #4a321f;
  --neat: "BNCE" 0, "INFM" 0;
  --loose: "BNCE" 35, "INFM" 70;
  color-scheme: dark;
}

* {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  background: var(--wall);
  color: var(--chalk);
  font-family: "Shantell Sans", "Comic Sans MS", "Segoe Print", sans-serif;
  font-variation-settings: var(--neat);
  font-size: clamp(1rem, 0.95rem + 0.25vw, 1.15rem);
  line-height: 1.6;
  overflow-x: hidden;
}

.defs {
  position: absolute;
}

.skip {
  position: absolute;
  left: -999px;
  top: 8px;
  background: var(--yellow);
  color: #111;
  padding: 8px 14px;
  border-radius: 6px;
  z-index: 10;
}
.skip:focus {
  left: 8px;
}

a {
  color: var(--chalk);
  text-decoration: underline;
  text-decoration-color: var(--yellow);
  text-decoration-thickness: 2px;
  text-underline-offset: 4px;
}
a:hover {
  color: var(--yellow);
}
:focus-visible {
  outline: 3px solid var(--yellow);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ---- A board: slate in a wooden frame, with the dust of old lectures ---- */

.board {
  position: relative;
  margin: clamp(10px, 2vw, 28px);
  padding: clamp(22px, 4vw, 64px);
  border: clamp(6px, 0.9vw, 12px) solid var(--wood);
  border-image: linear-gradient(175deg, #8d6441, var(--wood-dark) 55%, #6d4a2d) 1;
  background:
    radial-gradient(60% 40% at 18% 22%, rgba(255, 255, 255, 0.045), transparent 70%),
    radial-gradient(50% 35% at 82% 70%, rgba(255, 255, 255, 0.035), transparent 70%),
    radial-gradient(35% 25% at 55% 40%, rgba(255, 255, 255, 0.02), transparent 70%),
    url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='240' height='240'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.85' numOctaves='3' seed='7'/%3E%3CfeColorMatrix values='0 0 0 0 1  0 0 0 0 1  0 0 0 0 1  0 0 0 .09 0'/%3E%3C/filter%3E%3Crect width='240' height='240' filter='url(%23n)'/%3E%3C/svg%3E"),
    linear-gradient(180deg, var(--slate-hi), var(--slate) 30%);
  box-shadow:
    0 18px 40px rgba(0, 0, 0, 0.55),
    inset 0 0 90px rgba(0, 0, 0, 0.35);
}

.eyebrow {
  margin: 0 0 0.4em;
  color: var(--chalk-dim);
  font-size: 0.85em;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.chalk {
  font-variation-settings: var(--loose);
  font-weight: 700;
  filter: url(#chalk);
  line-height: 1.02;
  margin: 0;
}
h1.chalk {
  font-size: clamp(3.4rem, 9.5vw, 8.4rem);
  letter-spacing: -0.01em;
}
h2.chalk {
  font-size: clamp(2.3rem, 6vw, 4.8rem);
  margin-bottom: 0.3em;
}
h3.chalk {
  font-size: clamp(1.4rem, 2.6vw, 2rem);
  margin-bottom: 0.4em;
}

.big {
  font-size: 1.22em;
  line-height: 1.5;
}
.meta,
.aside {
  color: var(--chalk-dim);
  font-size: 0.9em;
}
.yellow {
  color: var(--yellow);
  font-weight: 600;
}

.links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4em 1.3em;
  font-weight: 600;
}

.cols {
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(0, 1fr);
  gap: clamp(20px, 4vw, 64px);
  align-items: start;
}
.cols.even {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}
.cols p:first-child {
  margin-top: 0;
}

/* ---- Element tiles ---- */

.tiles {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 0.7em 0 1em;
}
.el {
  --c: #fff;
  position: relative;
  display: inline-grid;
  place-items: center;
  width: 3.7em;
  height: 4.1em;
  padding-top: 0.5em;
  border: 2px solid color-mix(in srgb, var(--c) 70%, #fff);
  border-radius: 5px 7px 4px 8px;
  color: color-mix(in srgb, var(--c) 62%, #fff);
  background: color-mix(in srgb, var(--c) 12%, transparent);
  font-size: 1.3em;
  font-weight: 700;
  line-height: 1;
  font-variation-settings: var(--neat);
}
.el small {
  position: absolute;
  top: 3px;
  left: 5px;
  font-size: 0.44em;
  font-weight: 500;
  opacity: 0.9;
}
.el i {
  font-style: normal;
  font-size: 0.4em;
  font-weight: 500;
  opacity: 0.95;
  align-self: end;
  padding-bottom: 5px;
}
.tiles-note {
  flex: 1 1 14em;
  max-width: 22em;
  color: var(--chalk-dim);
  font-size: 0.85em;
  line-height: 1.35;
}
.small-tiles .el {
  font-size: 0.95em;
}
.or {
  color: var(--chalk-dim);
  padding: 0 4px;
}

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

.hero {
  display: grid;
  grid-template-columns: minmax(0, 0.82fr) minmax(0, 1fr);
  grid-template-areas: "words hold" "tray tray";
  gap: clamp(12px, 2.4vw, 40px);
  align-items: center;
  min-height: min(calc(100svh - 2 * clamp(10px, 2vw, 28px)), 1000px);
  padding-bottom: 0;
}
.lamp {
  position: absolute;
  inset: 0 0 auto;
  height: 46%;
  margin: 0;
  background: radial-gradient(70% 100% at 50% 0%, rgba(255, 244, 214, 0.1), transparent 70%);
  pointer-events: none;
}
.hero-words {
  grid-area: words;
  position: relative;
}
.lede {
  font-size: 1.25em;
  line-height: 1.45;
  max-width: 26em;
}
.how {
  max-width: 26em;
  color: var(--chalk-dim);
}
.hold {
  grid-area: hold;
  margin: 0;
  min-width: 0;
}
.stage-wrap {
  position: relative;
  width: 100%;
  aspect-ratio: 1 / 0.86;
}
/* On a wide screen the first board fits the window: the stage takes what the words and
   the two rows of the tray leave. */
@media (min-width: 901px) {
  .hero .stage-wrap {
    aspect-ratio: auto;
    height: clamp(300px, calc(100svh - 420px), 640px);
  }
  .hero h1.chalk {
    font-size: clamp(3.4rem, min(9.5vw, 12.5svh), 8.4rem);
  }
}
.stage {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  touch-action: none;
  cursor: grab;
  border-radius: 10px;
}
.stage.on-atom {
  cursor: pointer;
}
.stage.holding {
  cursor: grabbing;
}
.nojs {
  position: absolute;
  inset: 40% 10% auto;
  text-align: center;
}
.readout {
  margin: 0.2em 0 0;
  min-height: 1.6em;
  color: var(--yellow);
  font-weight: 600;
  font-size: 1.08em;
}
.hold .meta,
.mini .meta {
  margin: 0.15em 0 0;
}

.tray {
  grid-area: tray;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 22px;
  margin: 0 calc(-1 * clamp(22px, 4vw, 64px));
  padding: 14px clamp(22px, 4vw, 64px) 16px;
  background: linear-gradient(180deg, #8d6441, var(--wood-dark));
  box-shadow:
    inset 0 3px 0 rgba(255, 255, 255, 0.14),
    0 -10px 22px rgba(0, 0, 0, 0.35);
}
.pick {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
}
.tray button {
  font-size: 0.92em;
  padding: 0.4em 0.8em;
}
.tray-label {
  font-size: 0.8em;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: #f3dcc3;
  margin-right: 4px;
}
button {
  font: inherit;
  font-weight: 600;
  color: #23201a;
  background: var(--chalk);
  border: 0;
  border-radius: 4px 6px 5px 7px;
  padding: 0.42em 0.95em;
  min-height: 44px;
  cursor: pointer;
  box-shadow: 0 2px 0 rgba(0, 0, 0, 0.45);
  transition: transform 0.12s;
}
button:hover:not(:disabled) {
  transform: translateY(-2px);
}
button[aria-pressed="true"] {
  background: var(--yellow);
  box-shadow:
    0 2px 0 rgba(0, 0, 0, 0.45),
    0 0 0 2px rgba(255, 228, 92, 0.35);
}
button:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}
.eraser {
  margin-left: auto;
  display: inline-flex;
  align-items: center;
  gap: 10px;
  background: #2b2e33;
  color: var(--chalk);
  border-top: 9px solid #c9b79a;
  border-radius: 3px;
}
.eraser span {
  width: 18px;
  height: 10px;
  border-radius: 50%;
  background: radial-gradient(rgba(255, 255, 255, 0.7), transparent 70%);
}

/* ---- Splashery's two smaller boards ---- */

.facts {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
}
.facts li {
  padding-left: 16px;
  border-left: 3px solid var(--chalk-dim);
  border-radius: 2px;
  font-size: 0.95em;
}
.facts b {
  display: block;
  color: var(--yellow);
}
.pair {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(18px, 3vw, 44px);
  margin-top: clamp(26px, 4vw, 56px);
}
.mini {
  margin: 0;
  min-width: 0;
  padding: clamp(14px, 2vw, 26px);
  border: 2px dashed rgba(239, 236, 226, 0.32);
  border-radius: 14px 10px 16px 9px;
}
.mini .stage-wrap {
  aspect-ratio: 1 / 0.8;
}
.mini .pick {
  margin: 10px 0 8px;
}
.mini button {
  padding: 0.3em 0.7em;
  font-size: 0.92em;
}

.real {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.35fr);
  gap: clamp(18px, 3vw, 44px);
  align-items: center;
  margin: clamp(18px, 3vw, 44px) 0 0;
  padding: clamp(14px, 2vw, 26px);
  border: 2px dashed rgba(239, 236, 226, 0.32);
  border-radius: 10px 14px 9px 16px;
}
.real p:first-of-type {
  margin-top: 0;
}
.real-frame {
  display: grid;
  place-items: center;
  aspect-ratio: 4 / 3;
  border-radius: 12px;
  background: #0b0f10;
  box-shadow: inset 0 0 0 2px rgba(239, 236, 226, 0.18);
  overflow: hidden;
}
.real-frame > * {
  grid-area: 1 / 1;
}
.real-frame iframe {
  position: relative;
  width: 100%;
  height: 100%;
  border: 0;
  color-scheme: dark;
}
.real-wait {
  color: var(--chalk-dim);
}
.real-load {
  padding: 0.5em 1.1em;
  border-radius: 4px 6px 5px 7px;
  background: var(--yellow);
  color: #23201a;
  font-weight: 700;
  text-decoration: none;
  text-align: center;
  box-shadow: 0 2px 0 rgba(0, 0, 0, 0.45);
}
.real-load:hover {
  color: #23201a;
  transform: translateY(-2px);
}

/* ---- grooph's reaction scheme ---- */

.scheme {
  margin: 0;
}
.scheme svg {
  width: 100%;
  height: auto;
  overflow: visible;
}
.chalk-line {
  stroke: var(--chalk);
  stroke-width: 3;
  stroke-linecap: round;
  stroke-linejoin: round;
}
.slatefill {
  fill: var(--slate);
}
.stopfill {
  fill: #ff4d43;
  stroke: var(--chalk);
}
.scheme-text text {
  fill: var(--chalk);
  font-size: 21px;
  font-weight: 700;
  font-variation-settings: var(--loose);
}
.scheme-text .small {
  font-size: 15px;
  font-weight: 500;
  fill: var(--chalk-dim);
}
.runner {
  fill: var(--yellow);
  offset-path: path("M92 92 C 140 30, 232 30, 278 92 C 232 156, 140 156, 92 92");
  offset-distance: 0%;
  animation: run 5.5s linear infinite;
}
@keyframes run {
  to {
    offset-distance: 100%;
  }
}

/* ---- Isomers ---- */

.isomer {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 14px 22px;
  margin: 1em 0 0.4em;
}
.letters {
  display: flex;
  gap: 5px;
  margin: 0;
}
.letters span {
  display: grid;
  place-items: center;
  width: 1.75em;
  height: 1.75em;
  border-radius: 50%;
  border: 2px solid var(--chalk);
  font-weight: 700;
  font-size: clamp(0.95rem, 2.3vw, 1.3rem);
  background: rgba(239, 236, 226, 0.08);
}
.letters .gap {
  width: 0.7em;
  border: 0;
  background: none;
}

/* ---- The plainer list ---- */

.list {
  list-style: none;
  margin: 1.4em 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(18px, 3vw, 44px) clamp(24px, 4vw, 64px);
  counter-reset: item 4;
}
.list li {
  counter-increment: item;
  border-top: 2px solid rgba(239, 236, 226, 0.3);
  padding-top: 12px;
}
.list h3 {
  margin: 0 0 0.3em;
  font-size: 1.3em;
  font-variation-settings: var(--loose);
}
.list h3::before {
  content: counter(item) ". ";
  color: var(--yellow);
}
.list p {
  margin: 0 0 0.6em;
}
.list .last {
  grid-column: 1 / -1;
  font-size: 0.92em;
  color: var(--chalk-dim);
}
.list .last h3 {
  font-size: 1.1em;
  color: var(--chalk);
}

/* ---- Written in elements ---- */

.spell-label {
  display: block;
  margin-top: 1.2em;
  color: var(--yellow);
  font-weight: 600;
}
#spell-in,
#stock-find,
#own-code {
  width: 100%;
  max-width: 20em;
  margin-top: 6px;
  padding: 0.35em 0.2em;
  font: inherit;
  font-size: 1.6em;
  font-weight: 700;
  font-variation-settings: var(--loose);
  color: var(--chalk);
  background: transparent;
  border: 0;
  border-bottom: 3px solid var(--chalk);
  border-radius: 0;
}
.spell-out .tiles {
  margin-top: 0;
}
.spell-out .way + .way {
  margin-top: 6px;
}
.stuck b {
  color: #ff6b61;
}

.contact {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(9em, 1fr));
  gap: 12px 20px;
  font-size: 1.15em;
  font-weight: 600;
}

.foot {
  margin: clamp(10px, 2vw, 28px);
  padding: 10px clamp(12px, 3vw, 40px) 40px;
  color: #8c948c;
  font-size: 0.82em;
  max-width: 70em;
}

/* ---- The stockroom: a board that opens over the hall ---- */

#hero-extra {
  max-width: 11em;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.door {
  background: #2b2e33;
  color: var(--chalk);
  box-shadow:
    0 2px 0 rgba(0, 0, 0, 0.45),
    inset 0 0 0 2px rgba(239, 236, 226, 0.4);
}
.hero.dropping::after {
  content: "Drop it on the board";
  position: absolute;
  inset: 0;
  z-index: 5;
  display: grid;
  place-items: center;
  font-size: clamp(1.4rem, 4vw, 2.6rem);
  font-weight: 700;
  font-variation-settings: var(--loose);
  color: var(--yellow);
  background: rgba(28, 37, 38, 0.86);
  outline: 4px dashed var(--yellow);
  outline-offset: -18px;
  pointer-events: none;
}
.stockroom {
  width: min(1120px, calc(100vw - 20px));
  max-height: calc(100dvh - 20px);
  padding: clamp(16px, 3vw, 40px);
  color: var(--chalk);
  border: clamp(6px, 0.9vw, 12px) solid var(--wood);
  border-image: linear-gradient(175deg, #8d6441, var(--wood-dark) 55%, #6d4a2d) 1;
  background:
    radial-gradient(60% 40% at 18% 12%, rgba(255, 255, 255, 0.05), transparent 70%),
    linear-gradient(180deg, var(--slate-hi), var(--slate) 30%);
  box-shadow: 0 30px 80px rgba(0, 0, 0, 0.7);
  overscroll-behavior: contain;
}
.stockroom::backdrop {
  background: rgba(6, 10, 10, 0.74);
}
.stock-top {
  display: flex;
  justify-content: space-between;
  align-items: start;
  gap: 16px;
}
.stockroom h2.chalk {
  font-size: clamp(2rem, 5vw, 3.4rem);
}
#stock-find {
  font-size: 1.3em;
}
#stock-list section {
  margin-top: 1.5em;
}
#stock-list h3 {
  margin: 0 0 0.55em;
  font-size: 1.12em;
  color: var(--yellow);
  font-variation-settings: var(--loose);
}
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(9.6em, 1fr));
  gap: 8px;
}
.card {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  justify-content: center;
  gap: 1px;
  padding: 0.4em 0.7em;
  min-height: 56px;
  font-size: 0.95em;
  line-height: 1.2;
  text-align: left;
}
.card small {
  font-size: 0.78em;
  font-weight: 500;
  color: #5d584c;
}
.card[hidden],
#stock-list section[hidden] {
  display: none;
}
.own {
  margin-top: 2em;
  padding-top: 1.2em;
  border-top: 2px dashed rgba(239, 236, 226, 0.32);
}
.own-ways {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(18px, 3vw, 44px);
}
.own .spell-label {
  margin-top: 0.4em;
}
.own-row {
  display: flex;
  align-items: end;
  gap: 12px;
}
#own-code {
  width: 6.5em;
  font-size: 1.3em;
  text-transform: uppercase;
}
#own-file {
  display: block;
  max-width: 100%;
  margin-top: 10px;
  font: inherit;
  color: var(--chalk-dim);
}
#own-file::file-selector-button {
  margin-right: 12px;
  padding: 0.42em 0.95em;
  min-height: 44px;
  font: inherit;
  font-weight: 600;
  color: #23201a;
  background: var(--chalk);
  border: 0;
  border-radius: 4px 6px 5px 7px;
  box-shadow: 0 2px 0 rgba(0, 0, 0, 0.45);
  cursor: pointer;
}
#own-status:empty {
  display: none;
}

/* ---- Narrower rooms ---- */

@media (max-width: 900px) {
  /* The molecule comes straight after the name, so it is on the first screen. */
  .hero {
    grid-template-columns: minmax(0, 1fr);
    grid-template-areas: none;
    align-items: start;
    gap: 6px;
    min-height: 0;
  }
  .hero-words {
    display: contents;
  }
  .hero-words > *,
  .hold,
  .tray {
    grid-area: auto;
    position: relative;
  }
  .hero-words > .tiles {
    margin: 0.3em 0 0;
  }
  .hold {
    order: 1;
  }
  .how {
    order: 2;
    margin: 0.2em 0 0;
  }
  .lede {
    order: 3;
    margin: 0.5em 0 1em;
  }
  .tray {
    order: 4;
  }
  .hero .stage-wrap {
    aspect-ratio: 1 / 0.7;
  }
  .cols,
  .cols.even,
  .pair,
  .real,
  .own-ways {
    grid-template-columns: minmax(0, 1fr);
  }
  .eraser {
    margin-left: 0;
  }
}
@media (max-width: 560px) {
  .list {
    grid-template-columns: minmax(0, 1fr);
  }
  h1.chalk {
    font-size: clamp(2.5rem, 12.4vw, 3.4rem);
    white-space: nowrap;
  }
  .el {
    width: 3.5em;
    height: 3.8em;
    font-size: 1.05em;
  }
  .el i {
    font-size: 0.46em;
  }
  /* Seven tiles on one line: the names give way, and the label still reads them out. */
  .long {
    gap: 5px;
    flex-wrap: nowrap;
  }
  .long .el {
    flex: 1 1 0;
    width: auto;
    min-width: 0;
    height: 2.9em;
    padding-top: 0.35em;
  }
  .long .el i {
    display: none;
  }
  .hero .stage-wrap,
  .mini .stage-wrap {
    aspect-ratio: 1 / 0.92;
  }
  .tray {
    gap: 10px 14px;
  }
  .cards {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .card {
    overflow-wrap: anywhere;
  }
  .tray-label {
    flex-basis: 100%;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  .runner {
    animation: none;
    offset-distance: 12%;
  }
  button {
    transition: none;
  }
}