/* How a dollar has changed in America using the gold and silver standard.
   Gold and silver each carry their own colour, everywhere and only there.
   Literal metal (#D4AF37, #C0C0C0) reaches only 1.8:1 and 1.6:1 on this
   ground, so each metal is held to a legible value and given a deeper tone
   for text at body size. */

:root {
  --paper:    #EDEEE8;
  --ink:      #16181A;
  --ink-mute: #6B7069;
  --rule:     #C7CABF;
  --rule-firm:#A9AD9F;
  --field:    #F6F7F3;
  --gold:        #9A7317;
  --gold-deep:   #7A5A11;
  --silver:      #77797C;
  --silver-deep: #5C5F62;

  --metal: var(--ink);
  --metal-deep: var(--ink);

  --serif: "Fraunces", "Hoefler Text", Georgia, serif;
  --sans:  "Archivo", "Helvetica Neue", Helvetica, Arial, sans-serif;

  --measure: 62rem;
}

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

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

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.55;
  font-synthesis-weight: none;
}

a {
  color: inherit;
  text-decoration-color: var(--rule-firm);
  text-underline-offset: 0.18em;
}
a:hover { text-decoration-color: currentColor; }

:focus-visible {
  outline: 2px solid var(--gold);
  outline-offset: 3px;
}

.sheet {
  max-width: var(--measure);
  margin: 0 auto;
  padding: clamp(2.5rem, 7vw, 5.5rem) clamp(1.25rem, 5vw, 3rem) 4rem;
}

/* ---------- masthead ---------- */

.masthead__title {
  margin: 0;
  font-family: var(--serif);
  font-variation-settings: "opsz" 144, "SOFT" 0, "WONK" 1;
  font-weight: 400;
  font-size: clamp(2.4rem, 6.4vw, 4.1rem);
  line-height: 1.1;
  padding-bottom: 0.06em;
  letter-spacing: -0.02em;
  text-wrap: balance;
}

.masthead__lede {
  margin: 1.15rem 0 0;
  font-size: clamp(1.02rem, 1.9vw, 1.2rem);
  line-height: 1.55;
  color: var(--ink-mute);
  text-wrap: pretty;
}

mark {
  padding: 0.14em 0.45em 0.2em;
  background-color: transparent;
  background-repeat: no-repeat;
  background-size: 100% 100%;
  background-position: center;
  color: var(--ink);
  -webkit-box-decoration-break: clone;
  box-decoration-break: clone;
}
.mark-au { background-image: url("data:image/svg+xml,%3Csvg%20xmlns%3D%27http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%27%20viewBox%3D%270%200%20200%2044%27%20preserveAspectRatio%3D%27none%27%3E%3Cfilter%20id%3D%27r%27%20x%3D%27-14%25%27%20y%3D%27-40%25%27%20width%3D%27128%25%27%20height%3D%27180%25%27%20color-interpolation-filters%3D%27sRGB%27%3E%3CfeTurbulence%20type%3D%27fractalNoise%27%20baseFrequency%3D%270.09%200.35%27%20numOctaves%3D%272%27%20seed%3D%2711%27%20result%3D%27n%27%2F%3E%3CfeDisplacementMap%20in%3D%27SourceGraphic%27%20in2%3D%27n%27%20scale%3D%274%27%20xChannelSelector%3D%27R%27%20yChannelSelector%3D%27G%27%2F%3E%3C%2Ffilter%3E%3Cg%20filter%3D%27url%28%23r%29%27%3E%3Cpath%20d%3D%27M%202%2C17%20C%2024%2C10%2046%2C16%2072%2C12%20C%2098%2C8%20124%2C16%20150%2C11%20C%20172%2C7%20188%2C14%20198%2C9%20L%20197%2C33%20C%20176%2C39%20152%2C31%20126%2C36%20C%20100%2C41%2074%2C32%2048%2C37%20C%2028%2C40%2014%2C34%203%2C38%20Z%27%20fill%3D%27%23D4AF37%27%20fill-opacity%3D%270.62%27%2F%3E%3Cpath%20d%3D%27M%2014%2C16%20C%2040%2C12%2062%2C17%2086%2C14%20L%2085%2C21%20C%2060%2C24%2038%2C19%2013%2C23%20Z%27%20fill%3D%27%23F4E1A0%27%20fill-opacity%3D%270.5%27%2F%3E%3Cpath%20d%3D%27M%20104%2C30%20C%20130%2C34%20154%2C28%20190%2C31%20L%20189%2C36%20C%20152%2C33%20128%2C39%20103%2C35%20Z%27%20fill%3D%27%23D4AF37%27%20fill-opacity%3D%270.45%27%2F%3E%3C%2Fg%3E%3C%2Fsvg%3E"); }
.mark-ag { background-image: url("data:image/svg+xml,%3Csvg%20xmlns%3D%27http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%27%20viewBox%3D%270%200%20200%2044%27%20preserveAspectRatio%3D%27none%27%3E%3Cfilter%20id%3D%27r%27%20x%3D%27-14%25%27%20y%3D%27-40%25%27%20width%3D%27128%25%27%20height%3D%27180%25%27%20color-interpolation-filters%3D%27sRGB%27%3E%3CfeTurbulence%20type%3D%27fractalNoise%27%20baseFrequency%3D%270.09%200.35%27%20numOctaves%3D%272%27%20seed%3D%274%27%20result%3D%27n%27%2F%3E%3CfeDisplacementMap%20in%3D%27SourceGraphic%27%20in2%3D%27n%27%20scale%3D%274%27%20xChannelSelector%3D%27R%27%20yChannelSelector%3D%27G%27%2F%3E%3C%2Ffilter%3E%3Cg%20filter%3D%27url%28%23r%29%27%3E%3Cpath%20d%3D%27M%202%2C15%20C%2024%2C8%2046%2C14%2072%2C10%20C%2098%2C6%20124%2C14%20150%2C9%20C%20172%2C5%20188%2C12%20198%2C7%20L%20197%2C35%20C%20176%2C41%20152%2C33%20126%2C38%20C%20100%2C43%2074%2C34%2048%2C39%20C%2028%2C42%2014%2C36%203%2C40%20Z%27%20fill%3D%27%23A5ABB1%27%20fill-opacity%3D%270.62%27%2F%3E%3Cpath%20d%3D%27M%2014%2C14%20C%2040%2C10%2062%2C15%2086%2C12%20L%2085%2C19%20C%2060%2C22%2038%2C17%2013%2C21%20Z%27%20fill%3D%27%23E6EAEC%27%20fill-opacity%3D%270.5%27%2F%3E%3Cpath%20d%3D%27M%20104%2C32%20C%20130%2C36%20154%2C30%20190%2C33%20L%20189%2C38%20C%20152%2C35%20128%2C41%20103%2C37%20Z%27%20fill%3D%27%23A5ABB1%27%20fill-opacity%3D%270.45%27%2F%3E%3C%2Fg%3E%3C%2Fsvg%3E"); }

/* ---------- the conversion grid ---------- */

.convert {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr) minmax(0, 1.15fr);
  column-gap: clamp(1.5rem, 4vw, 3.25rem);
  grid-template-areas:
    "amount-h  head-m    head-d"
    "amount    gold-m    gold-d"
    "amount    silver-m  silver-d"
    "amount    cpi-h     ."
    "amount    cpi-m     cpi-d";
  margin: clamp(2.75rem, 6vw, 4.5rem) 0 0;
  padding: clamp(1.5rem, 3vw, 2rem) 0 clamp(1.75rem, 3.5vw, 2.5rem);
  border-top: 1px solid var(--rule-firm);
  border-bottom: 1px solid var(--rule-firm);
}

.head {
  display: flex;
  align-items: center;
  gap: 0.5em;
  min-height: 1.9rem;
  margin: 0 0 0.9rem;
  font-size: 0.68rem;
  font-weight: 600;
  font-stretch: 115%;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--ink-mute);
}
.head--amount  { grid-area: amount-h; }
.head--metal   { grid-area: head-m; }
.head--dollars { grid-area: head-d; }
.head--cpi     { grid-area: cpi-h; margin-top: 0.4rem; }

/* ---------- the fields, which must read as fields ---------- */

.amount { grid-area: amount; }

.box {
  display: flex;
  align-items: baseline;
  gap: 0.1em;
  padding: 0.5rem 0.7rem 0.6rem;
  background: var(--field);
  border: 1px solid var(--rule-firm);
  box-shadow: inset 0 1px 0 rgba(22, 24, 26, 0.05);
  transition: border-color 120ms ease, box-shadow 120ms ease;
}
.box:hover { border-color: var(--ink-mute); }
.box:focus-within {
  border-color: var(--gold);
  box-shadow: inset 0 0 0 1px var(--gold);
}

.box__prefix {
  font-family: var(--serif);
  font-variation-settings: "opsz" 96, "WONK" 1;
  font-size: clamp(1.4rem, 3vw, 1.9rem);
  color: var(--ink-mute);
}

.box__input {
  flex: 1;
  min-width: 0;
  width: 100%;
  border: 0;
  padding: 0;
  background: none;
  color: inherit;
  caret-color: var(--gold);
  font-family: var(--serif);
  font-variation-settings: "opsz" 96, "SOFT" 0, "WONK" 1;
  font-weight: 400;
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  line-height: 1.15;
  letter-spacing: -0.015em;
  font-variant-numeric: lining-nums tabular-nums;
}
.box__input:focus { outline: none; }
.box__input::placeholder { color: var(--rule-firm); }
.box__input[aria-invalid="true"] { color: var(--gold); }

/* a year typed inline, in the middle of a phrase */
.inline-field {
  display: inline-flex;
  padding: 0.05em 0.3em;
  background: var(--field);
  border: 1px solid var(--rule-firm);
  transition: border-color 120ms ease, box-shadow 120ms ease;
}
.inline-field:focus-within { box-shadow: inset 0 0 0 1px var(--gold); }
.inline-field:hover { border-color: var(--ink-mute); }
.inline-field:focus-within { border-color: var(--gold); }

.inline-field__input {
  width: 4.2ch;
  border: 0;
  padding: 0 0 0.05em;
  background: none;
  color: var(--ink);
  caret-color: var(--gold);
  font: inherit;
  font-variant-numeric: lining-nums tabular-nums;
  text-align: center;
}
.inline-field__input:focus { outline: none; }
.inline-field__input::-webkit-outer-spin-button,
.inline-field__input::-webkit-inner-spin-button { -webkit-appearance: none; margin: 0; }
.inline-field__input[type="number"] { -moz-appearance: textfield; appearance: textfield; }

/* a scale picked from a list, held to the same field idiom */
.scale {
  position: relative;
  display: inline-flex;
  align-items: center;
  background: var(--field);
  border: 1px solid var(--rule-firm);
  transition: border-color 120ms ease, box-shadow 120ms ease;
}
.scale:hover { border-color: var(--ink-mute); }
.scale:focus-within {
  border-color: var(--gold);
  box-shadow: inset 0 0 0 1px var(--gold);
}
.scale::after {
  content: "";
  position: absolute;
  right: 0.55em;
  width: 0.34em;
  height: 0.34em;
  border-right: 1px solid var(--ink-mute);
  border-bottom: 1px solid var(--ink-mute);
  transform: translateY(-0.14em) rotate(45deg);
  pointer-events: none;
}

.scale__select {
  margin: 0;
  border: 0;
  padding: 0.16em 1.7em 0.2em 0.55em;
  background: none;
  color: inherit;
  font: inherit;
  line-height: inherit;
  text-transform: inherit;
  letter-spacing: inherit;
  cursor: pointer;
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;
}
.scale__select:focus { outline: none; }

/* inside the amount box the select must not take the box's display face */
.scale--amount {
  flex: none;
  align-self: center;
  margin-left: 0.55rem;
}
.scale--amount .scale__select {
  font-family: var(--sans);
  font-size: 0.72rem;
  font-weight: 600;
  font-stretch: 115%;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--ink-mute);
}


.amount__year {
  margin: 0.85rem 0 0;
  font-size: 1.0625rem;
  color: var(--ink-mute);
}
.amount__year .inline-field__input { font-size: 1.0625rem; width: 4.4ch; }

.head--dollars .inline-field { vertical-align: baseline; }
.head--dollars .inline-field__input {
  width: 6.2ch;
  font-size: inherit;
  letter-spacing: inherit;
  color: var(--ink);
}

.hint {
  margin: 0.7rem 0 0;
  font-size: 0.72rem;
  letter-spacing: 0.02em;
  color: var(--ink-mute);
}

.visually-hidden {
  position: absolute;
  width: 1px; height: 1px;
  margin: -1px; padding: 0;
  overflow: hidden; clip: rect(0 0 0 0);
  white-space: nowrap; border: 0;
}


/* ---------- the two metal rows ---------- */

.cell[data-metal="gold"]   { --metal: var(--gold); }
.cell[data-metal="silver"] { --metal: var(--silver); }

.cell { padding-bottom: 1.1rem; align-self: baseline; }
.cell--metal.cell[data-metal="gold"]     { grid-area: gold-m; }
.cell--dollars.cell[data-metal="gold"]   { grid-area: gold-d; }
.cell--metal.cell[data-metal="silver"]   { grid-area: silver-m; }
.cell--dollars.cell[data-metal="silver"] { grid-area: silver-d; }
.cell--cpi-metal   { grid-area: cpi-m; }
.cell--cpi-dollars { grid-area: cpi-d; }
.cell--cpi-metal .metal__weight,
.cell--cpi-dollars .answer { color: var(--ink-mute); }
.cell--cpi-dollars .answer { font-size: clamp(1.55rem, 3.8vw, 2.2rem); }

.metal, .answer {
  margin: 0;
  line-height: 1.05;
  font-variant-numeric: lining-nums tabular-nums;
  overflow-wrap: break-word;
}

.metal {
  display: flex;
  align-items: baseline;
  gap: 0.42em;
}

.metal__stamp {
  font-size: 0.8rem;
  font-weight: 700;
  font-stretch: 122%;
  letter-spacing: 0.14em;
  color: var(--metal-deep);
}

.metal__weight {
  font-weight: 600;
  font-stretch: 116%;
  font-size: clamp(1.35rem, 3.4vw, 2rem);
  color: var(--metal);
}

.metal__unit {
  font-size: 0.78rem;
  font-weight: 500;
  font-stretch: 116%;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--metal-deep);
}

.answer {
  font-family: var(--serif);
  font-variation-settings: "opsz" 144, "SOFT" 0, "WONK" 1;
  font-weight: 400;
  font-size: clamp(1.9rem, 5vw, 2.9rem);
  letter-spacing: -0.02em;
}

.note {
  margin: 0.55rem 0 0;
  font-size: 0.76rem;
  color: var(--ink-mute);
  font-variant-numeric: lining-nums tabular-nums;
}

/* ---------- method ---------- */

.method {
  margin-top: clamp(3rem, 7vw, 5rem);
  padding-top: 1.4rem;
  border-top: 1px solid var(--rule);
  font-size: 0.8125rem;
  line-height: 1.65;
  color: var(--ink-mute);
}
.method p { margin: 0 0 0.9rem; break-inside: avoid; }

.method__body {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(2rem, 5vw, 3.5rem);
  align-items: start;
}
.method__part > :last-child { margin-bottom: 0; }

/* the formula, set as one line in the prose it belongs to */

.eq {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.45em;
  margin: 1.6rem 0;
  overflow-x: auto;
  font-family: var(--serif);
  font-variation-settings: "opsz" 48, "SOFT" 0, "WONK" 1;
  font-size: 1.2rem;
  line-height: 1.15;
  white-space: nowrap;
  color: var(--ink);
  font-variant-numeric: lining-nums tabular-nums;
}

/* the fraction is the first half; the rest sits beside it, on its rule */
.eq__frac {
  display: inline-flex;
  flex-direction: column;
  align-items: stretch;
  flex: none;
  text-align: center;
}
.eq__num { padding: 0 0.5em 0.16em; }
.eq__den {
  padding: 0.18em 0.5em 0.06em;
  border-top: 1px solid var(--ink);
}

.eq__rest { flex: none; }

/* the asterisk rides at cap height; drop it onto the line the = sits on */
.eq__mul {
  display: inline-block;
  transform: translateY(0.2em);
}

.eq sub {
  position: relative;
  bottom: -0.26em;
  padding-left: 0.03em;
  font-size: 0.62em;
  vertical-align: baseline;
  color: var(--ink-mute);
}

.method__head {
  margin: 0 0 0.9rem;
  font-size: 0.63rem;
  font-weight: 600;
  font-stretch: 115%;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--ink);
}

.method__stamp {
  margin: clamp(2rem, 4.5vw, 3rem) 0 0;
  padding-top: 1.1rem;
  border-top: 1px solid var(--rule);
  text-align: center;
  font-size: 0.63rem;
  font-stretch: 112%;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.status {
  margin: clamp(1.25rem, 3vw, 1.75rem) 0 0;
  font-size: 0.85rem;
  color: var(--gold-deep);
}
.status:empty { display: none; }

.colophon {
  margin: clamp(2.5rem, 6vw, 4rem) 0 0;
  padding-top: 1.2rem;
  border-top: 1px solid var(--rule);
  text-align: center;
  font-size: 0.7rem;
  font-stretch: 112%;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-mute);
}
.colophon span { padding: 0 0.35em; color: var(--rule-firm); }

/* ---------- narrow screens ---------- */

@media (max-width: 58rem) {
  .convert {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.1fr);
    grid-template-areas:
      "amount-h  amount-h"
      "amount    amount"
      "head-m    head-d"
      "gold-m    gold-d"
      "silver-m  silver-d"
      "cpi-h     ."
      "cpi-m     cpi-d";
  }
  .head--amount { margin-bottom: 0.8rem; }
  .head--metal, .head--dollars { margin-top: clamp(1.5rem, 4vw, 2rem); }
}

@media (max-width: 34rem) {
  .convert {
    grid-template-columns: minmax(0, 1fr);
    grid-template-areas:
      "amount-h"
      "amount"
      "head-m"
      "gold-m"
      "silver-m"
      "cpi-h"
      "cpi-m"
      "head-d"
      "gold-d"
      "silver-d"
      "cpi-d";
  }
  .head--dollars { margin-top: clamp(1.25rem, 4vw, 1.75rem); }
}

@media (max-width: 46rem) {
  .method__body { grid-template-columns: minmax(0, 1fr); }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

/* unlabelled minor ticks between the labelled ones */
.mark--minor::before {
  height: 6px;
  background: var(--rule-firm);
}