:root {
  color-scheme: light;

  --paper: #eaf0f2;
  --white: #f7fafb;

  --ink: #17202a;
  --muted: #697078;
  --line: #b8c3c8;

  --blue: #244b74;
  --blue-bright: #4e7da6;

  --green: #4d715f;

  --night: #17212d;
  --night-light: #253342;

  --yellow: #e3c75a;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  background: var(--paper);
}

html,
body {
  margin: 0;
  width: 100%;
  min-height: 100%;
}

body {
  min-height: 100vh;
  min-height: 100dvh;

  background: var(--paper);
  color: var(--ink);

  font-family:
    Georgia,
    "Times New Roman",
    serif;

  font-size: 19px;
  line-height: 1.65;
}

a {
  color: var(--blue);
}

button,
input {
  font: inherit;
}


/* header */

.site-header {
  display: flex;
  justify-content: space-between;
  align-items: center;

  padding:
    max(19px, env(safe-area-inset-top))
    max(28px, env(safe-area-inset-right))
    19px
    max(28px, env(safe-area-inset-left));

  border-bottom: 1px solid var(--line);

  font-family:
    Arial,
    Helvetica,
    sans-serif;
}

.site-name {
  color: var(--ink);

  font-size: 20px;
  font-weight: 700;

  text-decoration: none;
}

nav {
  display: flex;
  gap: 26px;
}

nav a {
  color: var(--ink);

  font-size: 13px;
  text-decoration: none;
}

nav a:hover {
  text-decoration: underline;
}


/* opening */

.opening {
  min-height: 91vh;
  min-height: 91dvh;

  display: flex;
  flex-direction: column;
  justify-content: center;

  padding:
    80px
    clamp(27px, 8vw, 125px);

  border-bottom: 1px solid var(--line);
}

.opening-label,
.small-label,
.margin-label {
  margin: 0;

  color: var(--blue);

  font-family:
    Arial,
    Helvetica,
    sans-serif;

  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.09em;
}

.opening h1 {
  margin: 35px 0 80px;

  max-width: 1100px;

  font-size: clamp(77px, 14vw, 175px);
  font-weight: 400;
  line-height: 0.84;
  letter-spacing: -0.075em;
}

.opening-bottom {
  display: grid;
  grid-template-columns: 1fr 1fr;

  width: min(650px, 100%);
  margin-left: auto;

  border-top: 1px solid var(--ink);
}

.opening-bottom p {
  margin: 0;
  padding: 13px 10px 0 0;
}

.opening-bottom p:first-child {
  font-size: 31px;
}


/* premise */

.premise {
  display: grid;
  grid-template-columns: 65px 1fr 300px;
  gap: clamp(35px, 7vw, 100px);

  padding:
    120px
    clamp(25px, 8vw, 125px);
}

.number {
  color: var(--blue);

  font-family:
    Arial,
    Helvetica,
    sans-serif;

  font-size: 12px;
  font-weight: 700;
}

.premise > div:nth-child(2) {
  max-width: 740px;
}

.premise .lead {
  margin-top: 0;

  font-size: clamp(34px, 5vw, 57px);
  line-height: 1.12;
}

.premise aside {
  align-self: end;

  border-top: 3px solid var(--blue);

  padding-top: 13px;

  color: var(--muted);

  font-size: 15px;
}

.premise aside strong {
  display: block;

  margin-bottom: 14px;

  color: var(--ink);

  font-size: 37px;
  font-weight: 400;
}


/* questions */

.questions {
  background: var(--white);

  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);

  padding:
    110px
    clamp(25px, 7vw, 110px);
}

.section-intro {
  display: grid;
  grid-template-columns: 0.55fr 1.45fr;
  gap: 50px;

  margin-bottom: 85px;
}

.section-intro > span {
  color: var(--blue);

  font-family:
    Arial,
    Helvetica,
    sans-serif;

  font-size: 11px;
  font-weight: 700;
}

.section-intro h2 {
  margin: 0;

  max-width: 700px;

  font-size: clamp(44px, 7vw, 82px);
  font-weight: 400;
  line-height: 1;
  letter-spacing: -0.045em;
}

.questions article {
  display: grid;
  grid-template-columns: 60px 1fr 1fr 190px;
  gap: 35px;

  padding: 32px 0;

  border-top: 1px solid var(--line);
}

.question-number {
  color: var(--blue);

  font-family:
    Arial,
    Helvetica,
    sans-serif;

  font-size: 12px;
}

.questions h3 {
  margin: 0;

  font-size: clamp(25px, 3vw, 36px);
  font-weight: 400;
  line-height: 1.2;
}

.questions article p {
  margin: 0;
}

.status {
  color: var(--blue);

  font-style: italic;
}


/* Zack */

.zack-note {
  padding:
    90px
    clamp(25px, 10vw, 160px);

  background: #e0dfd6;
}

.zack-note blockquote {
  max-width: 900px;

  margin: 35px 0 20px;

  font-size: clamp(31px, 5vw, 58px);
  line-height: 1.15;
}

.zack-note > p:not(.margin-label) {
  color: var(--muted);
}

.zack-note a {
  display: inline-block;

  margin-top: 25px;

  font-family:
    Arial,
    Helvetica,
    sans-serif;

  font-size: 14px;
}


/* scale */

.scale {
  position: relative;

  min-height: 100vh;
  min-height: 100dvh;

  overflow: hidden;

  padding:
    110px
    clamp(25px, 7vw, 110px);

  background: var(--night);
  color: #edf1ed;
}

.scale-heading {
  position: relative;
  z-index: 2;

  display: grid;
  grid-template-columns: 60px 1fr;
}

.scale-heading > span {
  color: #82a6c7;

  font-family:
    Arial,
    Helvetica,
    sans-serif;

  font-size: 12px;
}

.scale h2 {
  max-width: 800px;

  margin: 0;

  font-size: clamp(50px, 8vw, 100px);
  font-weight: 400;
  line-height: 0.95;
  letter-spacing: -0.055em;
}

.scale-body {
  position: relative;
  z-index: 2;

  width: min(600px, 55%);

  margin:
    100px
    0
    0
    auto;
}

.scale-body p {
  color: #c2ccd0;
}

.orbit {
  position: absolute;

  right: -150px;
  bottom: -220px;

  width: 720px;
  height: 720px;
}

.star {
  position: absolute;
  left: 50%;
  top: 50%;

  width: 44px;
  height: 44px;

  transform: translate(-50%, -50%);

  border-radius: 50%;

  background: var(--yellow);

  box-shadow: 0 0 55px rgba(227, 199, 90, 0.35);
}

.orbit-line {
  position: absolute;
  left: 50%;
  top: 50%;

  border: 1px solid #657485;
  border-radius: 50%;

  transform: translate(-50%, -50%);
}

.orbit-one {
  width: 210px;
  height: 210px;
}

.orbit-two {
  width: 390px;
  height: 390px;
}

.orbit-three {
  width: 620px;
  height: 620px;
}

.planet {
  position: absolute;

  left: 50%;
  top: -6px;

  width: 12px;
  height: 12px;

  transform: translateX(-50%);

  border-radius: 50%;

  background: #92aec3;
}

.orbit-two .planet {
  width: 16px;
  height: 16px;

  top: auto;
  left: auto;
  right: 15%;
  bottom: 11%;

  background: #70956f;
}

.orbit-three .planet {
  left: 4%;
  top: 32%;

  width: 9px;
  height: 9px;

  background: #c58f62;
}


/* Drake */

.drake {
  padding:
    120px
    clamp(25px, 8vw, 125px);

  background: var(--paper);
}

.drake-title {
  display: grid;
  grid-template-columns: 0.6fr 1.4fr;

  margin-bottom: 70px;
}

.drake-title span {
  color: var(--blue);

  font-family:
    Arial,
    Helvetica,
    sans-serif;

  font-size: 12px;
  font-weight: 700;
}

.drake-title h2 {
  margin: 0;

  font-size: clamp(45px, 7vw, 82px);
  font-weight: 400;
}

.equation {
  overflow-x: auto;

  padding: 50px 0;

  border-top: 1px solid var(--ink);
  border-bottom: 1px solid var(--ink);

  white-space: nowrap;

  font-size: clamp(27px, 5vw, 63px);
}

.drake-copy {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 45px;

  margin-top: 40px;

  color: var(--muted);
}


/* filters */

.filters {
  padding:
    110px
    clamp(25px, 7vw, 110px);

  background: var(--green);
  color: #f5f2e9;
}

.filters-title {
  display: grid;
  grid-template-columns: 60px 1fr;

  margin-bottom: 80px;
}

.filters-title > span {
  font-family:
    Arial,
    Helvetica,
    sans-serif;

  font-size: 12px;
}

.filters-title h2 {
  max-width: 950px;

  margin: 0;

  font-size: clamp(43px, 7vw, 84px);
  font-weight: 400;
  line-height: 1;
  letter-spacing: -0.04em;
}

.filters ol {
  list-style: none;

  margin: 0;
  padding: 0;
}

.filters li {
  display: grid;
  grid-template-columns: 60px 0.8fr 1.2fr;
  gap: 30px;

  padding: 24px 0;

  border-top: 1px solid rgba(255, 255, 255, 0.35);
}

.filters li > span {
  font-family:
    Arial,
    Helvetica,
    sans-serif;

  font-size: 11px;
}

.filters strong {
  font-size: 26px;
  font-weight: 400;
}

.filters li p {
  margin: 0;

  color: #d9e1d9;
}


/* Fermi */

.fermi {
  padding:
    130px
    clamp(25px, 8vw, 125px);

  background: #ede7d8;
}

.fermi-label {
  color: var(--blue);

  font-family:
    Arial,
    Helvetica,
    sans-serif;

  font-size: 11px;
  font-weight: 700;
}

.fermi > h2 {
  margin: 35px 0 80px;

  font-size: clamp(60px, 10vw, 125px);
  font-weight: 400;
  line-height: 0.88;
  letter-spacing: -0.065em;
}

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

  border-top: 1px solid var(--ink);
}

.fermi-columns > div {
  min-height: 240px;

  padding: 24px 28px 30px 0;

  border-bottom: 1px solid var(--line);
}

.fermi-columns strong {
  display: block;

  margin-bottom: 18px;

  font-size: 22px;
  font-weight: 400;
}

.fermi-columns p {
  max-width: 330px;

  color: var(--muted);
}

.fermi-end {
  margin: 90px 0 0 auto;

  max-width: 650px;

  font-size: clamp(31px, 5vw, 55px);
  line-height: 1.2;
}


/* evidence */

.evidence {
  padding:
    120px
    clamp(25px, 7vw, 110px);

  background: var(--white);
}

.evidence-heading {
  display: grid;
  grid-template-columns: 60px 1fr;

  margin-bottom: 80px;
}

.evidence-heading > span {
  color: var(--blue);

  font-family:
    Arial,
    Helvetica,
    sans-serif;

  font-size: 12px;
}

.evidence-heading h2 {
  max-width: 850px;

  margin: 0;

  font-size: clamp(45px, 7vw, 82px);
  font-weight: 400;
  line-height: 1;
}

.evidence-scale {
  display: grid;
  grid-template-columns: repeat(4, 1fr);

  border-top: 3px solid var(--ink);
}

.evidence-scale > div {
  min-height: 320px;

  padding:
    19px
    28px
    30px
    0;

  border-bottom: 1px solid var(--line);
}

.level {
  display: block;

  margin-bottom: 60px;

  color: var(--blue);

  font-family:
    Arial,
    Helvetica,
    sans-serif;

  font-size: 11px;
  font-weight: 700;
}

.evidence-scale strong {
  display: block;

  margin-bottom: 22px;

  font-size: 25px;
  font-weight: 400;
  line-height: 1.15;
}

.evidence-scale p {
  color: var(--muted);
}


/* slider */

.uncertainty {
  display: grid;
  grid-template-columns: 1.3fr 0.7fr;
  gap: 80px;

  padding:
    100px
    clamp(25px, 8vw, 125px);

  background: var(--blue);
  color: white;
}

.uncertainty h2 {
  max-width: 800px;

  margin: 30px 0 60px;

  font-size: clamp(41px, 6vw, 72px);
  font-weight: 400;
  line-height: 1;
}

.uncertainty .small-label {
  color: #d6e5ef;
}

#universe-slider {
  width: 100%;

  accent-color: var(--yellow);

  cursor: pointer;
}

.slider-labels {
  display: flex;
  justify-content: space-between;

  margin-top: 10px;

  font-family:
    Arial,
    Helvetica,
    sans-serif;

  font-size: 11px;
}

.result {
  align-self: end;

  border-top: 1px solid rgba(255, 255, 255, 0.6);

  padding-top: 20px;
}

#slider-number {
  display: block;

  font-size: clamp(65px, 10vw, 120px);
  line-height: 1;
}

#slider-response {
  font-size: 20px;
}

.result-note {
  margin-top: 45px;

  color: #d2e2ed;

  font-size: 13px;
}


/* pigeon */

.pigeon-footnote {
  padding:
    50px
    clamp(25px, 8vw, 125px);

  border-bottom: 1px solid var(--line);

  background: #dddcd6;

  font-size: 14px;
}

.pigeon-footnote p {
  margin: 0 0 6px;
}

.pigeon-footnote a {
  display: inline-block;

  margin-top: 12px;
}


/* reading */

.reading {
  display: grid;
  grid-template-columns: 0.7fr 1.3fr;
  gap: 80px;

  padding:
    110px
    clamp(25px, 8vw, 125px);
}

.reading h2 {
  margin: 30px 0 0;

  max-width: 520px;

  font-size: clamp(47px, 7vw, 80px);
  font-weight: 400;
  line-height: 1;
}

.reading-links {
  border-top: 1px solid var(--ink);
}

.reading-links a {
  display: block;

  padding: 20px 0;

  border-bottom: 1px solid var(--line);

  color: var(--ink);

  font-size: 21px;

  text-decoration: none;
}

.reading-links a:hover {
  color: var(--blue);
}

.reading-links span {
  display: block;

  margin-bottom: 3px;

  color: var(--muted);

  font-family:
    Arial,
    Helvetica,
    sans-serif;

  font-size: 11px;
}


/* ending */

.ending {
  min-height: 86vh;
  min-height: 86dvh;

  display: flex;
  flex-direction: column;
  justify-content: center;

  padding:
    100px
    clamp(25px, 9vw, 145px);

  background: var(--night);
  color: #f2f0e8;
}

.ending p {
  max-width: 950px;

  margin: 0 0 32px;

  font-size: clamp(43px, 7vw, 88px);
  line-height: 1.02;
  letter-spacing: -0.045em;
}

.ending p:nth-child(2) {
  color: #92b1c9;
}

.ending button {
  appearance: none;

  width: fit-content;

  margin-top: 60px;

  border: 0;
  border-bottom: 1px solid #b3c7d6;

  padding: 0 0 4px;

  background: transparent;
  color: #b3c7d6;

  cursor: pointer;
}


/* mobile */

@media (max-width: 720px) {
  body {
    font-size: 18px;
  }

  .site-header {
    padding-left: 18px;
    padding-right: 18px;
  }

  nav {
    gap: 12px;

    overflow-x: auto;

    white-space: nowrap;
  }

  .opening {
    min-height: 92dvh;

    padding-left: 20px;
    padding-right: 20px;
  }

  .opening h1 {
    font-size: clamp(70px, 25vw, 112px);
  }

  .opening-bottom {
    grid-template-columns: 1fr;
  }

  .premise {
    grid-template-columns: 1fr;

    padding:
      85px
      20px;
  }

  .premise aside {
    margin-top: 30px;
  }

  .section-intro {
    grid-template-columns: 1fr;

    gap: 25px;
  }

  .questions {
    padding:
      80px
      20px;
  }

  .questions article {
    grid-template-columns: 35px 1fr;

    gap: 20px;
  }

  .questions article > p {
    grid-column: 2;
  }

  .zack-note {
    padding:
      75px
      20px;
  }

  .scale {
    min-height: 100dvh;

    padding:
      90px
      20px;
  }

  .scale-heading,
  .filters-title,
  .evidence-heading {
    grid-template-columns: 35px 1fr;
  }

  .scale-body {
    width: 100%;

    margin-top: 80px;
  }

  .orbit {
    right: -420px;
    bottom: -250px;
  }

  .drake {
    padding:
      85px
      20px;
  }

  .drake-title {
    grid-template-columns: 1fr;

    gap: 20px;
  }

  .drake-copy {
    grid-template-columns: 1fr;

    gap: 10px;
  }

  .filters {
    padding:
      85px
      20px;
  }

  .filters li {
    grid-template-columns: 35px 1fr;
  }

  .filters li p {
    grid-column: 2;
  }

  .fermi {
    padding:
      90px
      20px;
  }

  .fermi-columns {
    grid-template-columns: 1fr;
  }

  .fermi-columns > div {
    min-height: 0;
  }

  .evidence {
    padding:
      85px
      20px;
  }

  .evidence-scale {
    grid-template-columns: 1fr;
  }

  .evidence-scale > div {
    min-height: 0;
  }

  .level {
    margin-bottom: 25px;
  }

  .uncertainty {
    grid-template-columns: 1fr;

    padding:
      85px
      20px;
  }

  .reading {
    grid-template-columns: 1fr;

    padding:
      85px
      20px;
  }

  .ending {
    min-height: 90dvh;

    padding:
      90px
      20px;
  }
}