:root {
  --pm: #0fa0ce;
  --bd: #e1e1e1;
  --bg: #fff;
  --ft: #222;
  --tag: #333;

  --w-mobile: 640px;
}

html.dark {
  --bg: #262d33;
  --ft: #eee;
  --bd: #555;
  --tag: #999;
}

body {
  font-family: Helvetica, sans-serif;
  max-width: var(--w-mobile);
  margin: 50px auto 0;
  font-size: 16px;
  font-weight: 400;
  color: var(--ft);
  background-color: var(--bg);
  transition-property: background-color, border-color, color;
  transition-duration: .5s;
}

h1,h2,h3,h4,h5 {
  font-family: 'Noto Serif SC', 'Times New Roman', sans-serif;
  font-weight: 700;
  line-height: 1.5;
}

p {
  margin-top: 0;
  line-height: 1.5;
  text-align: left;
}

hr {
  margin: 30px 0;
  border-width: 0;
  border-top: 1px solid var(--bd);
}

pre,
code {
  font-family: Menlo, Monaco, Consolas, "Courier New", monospace;
  font-size: 13px;
}

a {
  text-decoration: none;
}

a:not(.icon) {
  color: inherit;
  text-decoration: underline;
  text-decoration-color: var(--pm);
  background-image: linear-gradient( to bottom, rgba(0, 0, 0, 0) 50%, var(--pm) 50% );
  background-size: 100% 200%;
  transition: background-position .2s ease-in-out;
}

a:not(.icon):hover,
a:not(.icon):focus {
  background-position: 0 100%;
  color: #fff;
}

a.icon:hover {
  transform: translateY(-5px);
  transition: transform .3s ease-in-out;
}

main {
  animation: showup 0.7s;
}

.row {
  display: flex;
  align-items: center;
}

.col {
  display: flex;
  flex-direction: column;
}

.jc-bt {
  justify-content: space-between;
}

.as-s {
  align-self: start;
}

.ai-c {
  align-items: center;
}

.gap-0_5 {
  gap: .8rem;
}

.gap-1 {
  gap: 1rem;
  row-gap: 1rem;
}

.gap-2 {
  gap: 2rem;
  row-gap: 2rem;
}

.gap-3 {
  gap: 3rem;
  row-gap: 3rem;
}

.lg-1 {
  font-size: 1.2em;
}

.sm-1 {
  font-size: .8em;
}

.mtb-1 {
  margin: 1em 0;
}

.mtb-2 {
  margin: 2em 0;
}

.mb-1 {
  margin-bottom: 1em;
}

.mb-0 {
  margin-bottom: 0;
}

.mt-2 {
  margin-top: 2em;
}

.ml-1 {
  margin-left: 1em;
}

.mw-6 {
  min-width: 6em;
}

.c-tag {
  color: var(--tag);
}

.btn {
  cursor: pointer;
}

.hidden {
  display: none;
}

.tag-pm {
  font-size: .7em;
  font-weight: bold;
  line-height: 1;
  color: #fff;
  background-color: var(--pm);
  border-radius: 20px;
  padding: 2px 8px;
}

details.toc ul {
  list-style-type: none;
  padding-inline-start: 1em;
  margin: 0;
}

details.toc ul>li {
  margin: 1em 0;
}

@keyframes showup {
  from {
    opacity: 0;
    transform: translateY(20px);
  }

  to {
    opacity: 1;
    transform: none;
  }
}

@media (max-width: 640px) {
  body {
    margin: 1em 2em;
  }

  .row-mob {
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
    row-gap: 0;
  }

  .al-c-mob {
    align-items: center;
  }

  .col-rev-mob {
    flex-direction: column-reverse;
  }

  .sm-2-mob {
    font-size: .9em;
  }

  .mb-0_5-mob {
    margin-bottom: .5em;
  }

  .mb-1_5-mob {
    margin-bottom: 1.5em;
  }
}

/* Scroll bar */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

::-webkit-scrollbar-thumb {
  background: rgb(128 128 128 / 70%);
}
::-webkit-scrollbar-thumb:window-inactive {
  background: rgb(128 128 128 / 20%);
}

::-webkit-scrollbar-thumb:active {
  background-color: rgb(128 128 128 / 100%);
}