:root {
  /* Base colors */
  --color-bg: #ffffff;
  --color-text: #000000;
  --color-accent: #13e741;
  --color-footer-bg: #000000;
  --color-footer-text: #c4c4c4;
  --color-spine-bg: #a0ba8b;
  --color-menu-bg: #c4c4c4;
  --color-scrollbar: #888888;
  --color-scrollbar-hover: #ffffff;
  --color-reverse-bg: #000000;
  --color-reverse-text: #ffffff;
}

/* Reset & base */
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
body {
  background-color: var(--color-bg);
  color: var(--color-text);
  font-family: 'Inter', Arial, sans-serif;
  font-size: 16px;
  display: flex;
  flex-direction: column;
}
main {
  position: sticky;
  top: 0;
  min-height: 100vh;
}
@media (hover: none) and (pointer: coarse) {
  main {
    min-height: 100svh;
  }
}

/* Flex utilities */
.flex-row { display: flex; flex-direction: row; }
.flex-column { display: flex; flex-direction: column; }
.wrap { flex-wrap: wrap; }
.grow-1 { flex-grow: 1; }
.flex-1 { flex: 1; }
.flex-2 { flex: 2; }
.gap-xs { gap: 0.25rem; }
.gap-sm { gap: 0.5rem; }
.gap-md { gap: 1rem; }
.gap-lg { gap: 2rem; }

/* Alignment */
.justify-center { justify-content: center; }
.justify-space { justify-content: space-between; }
.justify-end { justify-content: flex-end; }
.align-center { align-items: center; }
.align-end { align-items: flex-end; }

/* Container & box */
.footer {
  padding: 0.5rem;
  background-color: var(--color-footer-bg);
  color: var(--color-footer-text);
}
.box {
  padding: 0.5rem;
  user-select: none;
  transition: background-color 10s ease;
}
.box img {
  object-fit: cover;
  max-height: 60vh;
  max-width: 100%;
  filter: grayscale(100%);
}

/* Animations */
.box img,
.box h3,
.box button {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: opacity 10s ease, visibility 10s ease;
}
.box .visible {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
}
.box .waiting {
  cursor: default;
  text-decoration: none;
  pointer-events: none;
}

/* Components */
.spine {
  width: 2rem;
  padding: 0.5rem;
  background-color: var(--color-spine-bg);
  writing-mode: vertical-rl;
  text-orientation: mixed;
  user-select: none;
  transition: all 0.6s ease;
}
.spine a {
  text-decoration: none;
}
.spine a:active {
  color: var(--color-reverse-text);
}
.menu {
  background-color: var(--color-menu-bg);
  padding: 0.5rem;
  min-height: 100vh;
  z-index: 2;
}
.menu p {
  font-size: 1.25rem;
}
.menu a {
  color: var(--color-menu-bg);
}
.reverse {
  color: var(--color-reverse-text);
  background-color: var(--color-reverse-bg);
}
.reverse button {
  color: var(--color-reverse-text);
}

/* Typography & elements */
h1 {
  text-transform: uppercase;
}
a,
button {
  user-select: none;
  -webkit-tap-highlight-color: transparent;
}
a {
  color: var(--color-text);
}
button {
  cursor: pointer;
  font-size: 1.25rem;
  width: fit-content;
  align-self: center;
  font-weight: 700;
  background: none;
  border: none;
  text-decoration: underline;
}
button:disabled {
  pointer-events: none;
}
a:active,
button:active {
  color: var(--color-accent);
}
.link {
    font-size: 1.5rem;
    font-weight: bold;
    text-transform: uppercase;
}

/* Scrollbar & selection */
::-webkit-scrollbar {
  width: 0.5rem;
  display: none;
}
::-webkit-scrollbar-track {
  background: none;
}
::-webkit-scrollbar-thumb {
  background: var(--color-scrollbar);
}
::-webkit-scrollbar-thumb:hover {
  background: var(--color-scrollbar-hover);
}

html {
  -ms-overflow-style: none;
  scrollbar-width: none;
}

::selection {
  color: var(--color-accent);
  background: var(--color-reverse-bg);
}

/* Media queries */
@media (hover: hover) and (pointer: fine) {
  a:hover,
  button:hover {
    color: var(--color-accent);
  }
  .spine a:hover {
    color: var(--color-reverse-text);
  }
}
@media only screen and (max-width: 767px) {
  h1 { font-size: 1.5rem; }
  h2 { font-size: 1.25rem; }
  .menu div { flex-direction: column; }
}