:root {
  /* Sizes */
  --rhythm: 1.6;
  --spacing: calc(var(--rhythm) * 1rem);
  --max-content-width: 90rem;
  --min-tap-size: 48px;

  /* Colors */
  --color-purple: oklch(66% 0.2 306);
  --color-lavender: oklch(70% 0.15 306);
  --color-pink: oklch(70% 0.15 348);
  --color-yellow: oklch(85% 0.1 108);
  --color-cyan: oklch(85% 0.1 190);
  --color-cyan-light: oklch(88% 0.03 190);

  --color-background: oklch(16% 0.011 248);
  --color-text: oklch(75% 0.018 248);
  --color-text-bright: #fff;

  background-color: var(--color-background);
  color-scheme: dark;
  overflow-x: clip;
}

*,
*::before,
*::after {
  background-repeat: no-repeat;
  box-sizing: border-box;
}

body {
  background-color: var(--color-background);
  color: var(--color-text);
  font-family: Inter, Roboto, 'Helvetica Neue', 'Arial Nova', 'Nimbus Sans', Arial, sans-serif;
  font-size: clamp(1rem, 0.904rem + 0.481vw, 1.25rem);
  line-height: var(--rhythm);
  justify-content: space-between;
  margin: 0;
  min-height: 100dvh;
  position: relative;
}

body,
main,
header {
  display: flex;
  gap: var(--spacing);
  flex-direction: column;
  position: relative;
}

main,
header {
  align-self: center;
  max-width: var(--max-content-width);
  width: 100%;
}

header {
  flex: 0;
  flex-direction: row;
  justify-content: space-between;
  align-items: center;
  padding-block: var(--spacing);
  text-align: center;
  z-index: 100;
}

main {
  flex: 1;
  justify-content: center;
}

/* Header styles */

.warning {
  display: none;
}

.site-navigation {
  flex: 1;
}

.nav-list {
  gap: var(--spacing);
  margin: 0;
  padding: 0;

  & li,
  & a {
    display: block;
  }

  & a {
    text-decoration: none;
    padding: 0.25em 0.5em;
  }

  li:first-child,
  & li:has(.button) {
    margin-inline-start: auto;
  }

  & li:has(.button) {
    margin-inline-end: var(--spacing);
  }
}

/* Header page title */
h1 {
  border-block: 1px solid transparent; /* alignment with button/links */
  font-size: 1em;
  font-weight: 200;
  line-height: var(--rhythm);
  letter-spacing: 0.02em;
  margin: 0;
  padding-block: 0.25em; /* Match links */
  white-space: nowrap;

  & span {
    color: var(--color-text-bright);
    font-weight: 700;
  }
}

/* Section title */

h2 {
  font-size: clamp(2rem, 1.231rem + 3.846vw, 4rem);
  font-weight: 200;
  line-height: 1.1;
  text-wrap: balance;
  margin: 0;
  margin-block-end: var(--spacing);

  & span {
    color: var(--color-cyan);
  }

  /* Behold, the lone media query in this entire document */
  @media (min-width: 40rem) {
    font-weight: 100;
  }
}

a {
  color: var(--color-text-bright);
  font-weight: 500;
  text-underline-offset: 0.25em;
  text-decoration-thickness: 1px;
  transition: 0.25s;

  &:hover,
  &:focus {
    color: var(--color-cyan);
  }
}

p {
  margin: 0;
  margin-block-end: var(--spacing);
}

footer {
  font-size: 0.8em;
  text-align: center;
  margin-inline: auto;
  position: relative;
  width: max-content;
  max-width: 100%;
  z-index: 2;

  &::before {
    content: '';
    position: absolute;
    inset: 0;

    background-color: var(--color-background);
    filter: blur(20px);
    opacity: 0.6;
  }

  p {
    margin-block: calc(var(--spacing) / 2);
    margin-inline: var(--spacing);
    position: relative;
  }
}

.visually-hidden {
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  overflow: hidden;
  position: absolute;
  white-space: nowrap;
  width: 1px;
  height: 1px;
}

:root {
  /* Background glows */
  --color-glow-yellow: oklch(98% 0.01 108);
  --color-glow-teal: oklch(92.73% 0.04 190);
  --color-glow-pink: oklch(92.73% 0.04 348);
  --color-glow-blue: oklch(80% 0.04 248);
  --color-glow-purple: oklch(30% 0.075 306);

  /* --color-text: oklch(96% 0.032 107); */

  /* Kitten image */
  --image-width: min(265px, 28vw);
  --image-height: calc(var(--image-width) * 2.1283);
  --image-clip-offset: 0.15094;
  --image-outline-width: 1px;
  --image-outline-color: oklch(70% 0.2 318);

  --image-aware-padding: max(var(--spacing), var(--image-width) * 0.14);
}

body {
  padding-block-start: var(--spacing);
  padding-inline: var(--image-aware-padding);

  /* Background glows */
  &::before,
  &::after {
    content: '';
    position: absolute;
    inset: 0;
    pointer-events: none;
    mix-blend-mode: color-dodge;
    opacity: 0.6;
    z-index: 0;
  }

  /* Top left background glow */
  &::before {
    --light-size: 70vmin;

    background-image: radial-gradient(circle at center, var(--color-glow-yellow), black 70%);
    background-size: var(--light-size) var(--light-size);
    background-position: calc(50% - min(100vw, var(--max-content-width)) / 2 + 5vw) calc(var(--light-size) / -2 - 2vmin);
  }

  /* Bottom right background glow */
  &::after {
    --light-size: 100vw;

    background-image: radial-gradient(circle at center, var(--color-glow-blue), black 70%);
    background-size: var(--light-size) var(--light-size);
    background-position: calc(100% + var(--light-size) / 2 + 2vmin) calc(100% + var(--light-size) / 2 + 2vmin);
  }
}

main {
  &::before,
  &::after {
    content: "";
    position: fixed;
    inset: 0;
    pointer-events: none;
  }

  /* Wall */
  &::before {
    --background-size: 70vmax;
    --border-position: calc(var(--image-width) * var(--image-clip-offset) - var(--image-outline-width));

    background-image: radial-gradient(circle at center, var(--color-glow-purple), transparent 70%);
    background-size: var(--background-size) var(--background-size);
    background-position: calc(100% + var(--background-size) / 2) 50%;

    border-inline-end: var(--image-outline-width) solid var(--image-outline-color);
    border-image: linear-gradient(transparent, var(--image-outline-color), transparent) 1%;
    inset-inline-end: var(--border-position);
    opacity: 0.5;
    z-index: 1;
  }

  /* Kitten */
  &::after {
    --gradient-clip: calc(var(--image-clip-offset) * 100% - var(--image-outline-width));

    background-image: url("https://bumpbot.fun/kitten-peek-transparent.png"),
      linear-gradient(90deg, var(--color-background) var(--gradient-clip), transparent var(--gradient-clip));
    background-position: 0% calc(50% + var(--spacing));
    background-size: var(--image-width) auto;
    min-height: calc(var(--image-height) + var(--spacing) * 5);
    transform: scaleX(-1);
    z-index: 2;
  }

  & > * {
    margin-inline-end: calc(var(--image-width) - var(--image-aware-padding));
  }
}

.left-content,
.right-content {
  max-width: 50ch;
  position: relative;
  z-index: 10;
}

@property --gradient-start {
  syntax: '<color>';
  inherits: false;
  initial-value: pink;
}

@property --gradient-end {
  syntax: '<color>';
  inherits: false;
  initial-value: purple;
}

/* Links */

main a {
  --gradient-start: var(--color-pink);
  --gradient-end: var(--color-lavender);

  background-image: linear-gradient(90deg, var(--gradient-start), var(--gradient-end));
  background-clip: text;
  color: transparent;
  transition: --gradient-start 0.5s, --gradient-end 0.5s;

  &:hover,
  &:focus {
    --gradient-start: var(--color-cyan);
    --gradient-end: var(--color-yellow);

    color: transparent;
  }
}

.button.button {
  background: linear-gradient(45deg, var(--color-lavender), var(--color-cyan));
  border-radius: var(--spacing);
  border: 1px solid transparent;
  color: var(--color-background);
  font-weight: 600;
  padding-inline: var(--spacing);
  position: relative;
  transition: 0.1s;

  &::before,
  &::after {
    content: '';
    border-radius: inherit;
    transition: 0.25s ease-out;
    position: absolute;
    inset: 0;
    pointer-events: none;
  }

  /* Gradient shadow */
  &::before {
    inset: 0.2em;
    transform-origin: bottom;
    transform: scaleY(0.5);
    opacity: 0;
    z-index: -1;

    background: linear-gradient(45deg, var(--color-lavender), var(--color-cyan));
    filter: blur(calc(var(--spacing) / 2)) saturate(2);
  }

  &:hover,
  &:focus {
    background: var(--color-background);
    border-color: var(--color-lavender);
    color: var(--color-text-bright);
    font-weight: 400;
    letter-spacing: 0.01em;

    &::before,
    &::after {
      transform: none;
      opacity: 1;
    }
  }
}

/* Menu buttons */
.mobile-menu-button {
  --width: var(--min-tap-size);
  --height: var(--min-tap-size);

  --line-thickness: 2px;
  --line-spacing: 3px;

  cursor: pointer;
  display: block;
  position: absolute;
  inset-inline-end: var(--spacing);
  width: var(--width);
  height: var(--height);
  z-index: 100;

  & input {
    cursor: pointer;
    position: absolute;
    inset: 0;
    opacity: 0;
  }

  &::before,
  &::after {
    --width: 100%;
    --height: 100%;

    content: '';
    position: absolute;
    inset-inline-start: 0;
    width: var(--width);
    height: var(--height);
  }

  &:hover,
  &:focus {
    &::before,
    &::after {
      --color-text-bright: var(--color-cyan);
    }
  }
}

.hamburger-icon {
  clip-path: polygon(0 0, 100% 0, 100% 100%, 50% 100%);

  &::before,
  &::after {
    --height: calc(var(--line-thickness) * 3 + var(--line-spacing) * 2);

    inset-block-start: calc(50% - var(--height) / 2);
  }

  &::before {
    border-block: var(--line-thickness) solid var(--color-text-bright);
  }

  &::after {
    border-block-start: var(--line-thickness) solid var(--color-text-bright);
    margin-block-start: calc(var(--line-thickness) + var(--line-spacing));
  }
}

.close-icon {
  inset-block-start: calc(var(--spacing) * 2);
  inset-inline-end: calc(var(--spacing) + var(--image-aware-padding));

  &::before,
  &::after {
    --width: 75%;
    --height: 0;

    border-block-start: var(--line-thickness) solid var(--color-text-bright);
    transform-origin: 50% 50%;
    margin-inline: auto;
    inset-block-start: calc(50% - var(--line-thickness) / 2);
    inset-inline: 0;
  }

  &::before {
    transform: rotate(45deg);
  }

  &::after {
    transform: rotate(-45deg);
  }
}