:root {
  --bg: #000000;
  --card: #1C1C1E;
  --control: #2C2C2E;
  --accent: #30D158;
  --text: #FFFFFF;
  --text-secondary: rgba(235, 235, 245, 0.55);
  --radius: 22px;
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  padding: 0 24px 96px;
  background: var(--bg);
  color: var(--text);
  font-family: "Helvetica Neue", Helvetica, -apple-system, BlinkMacSystemFont, Arial, sans-serif;
  font-size: 17px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

.wrap {
  max-width: 620px;
  margin: 0 auto;
}

/* ---- header ---- */

header {
  padding: 72px 0 0;
}

.mark {
  display: block;
  margin-bottom: 28px;
}

h1 {
  font-size: 34px;
  font-weight: 600;
  letter-spacing: -0.4px;
  margin: 0 0 10px;
}

.lede {
  font-size: 21px;
  line-height: 1.45;
  color: var(--text-secondary);
  margin: 0;
  max-width: 34ch;
}

/* ---- generic type ---- */

h2 {
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.2px;
  color: var(--accent);
  margin: 44px 0 14px;
}

h3 {
  font-size: 17px;
  font-weight: 600;
  margin: 26px 0 8px;
}

p {
  margin: 0 0 16px;
}

.muted {
  color: var(--text-secondary);
}

.small {
  font-size: 15px;
}

ul {
  margin: 0 0 16px;
  padding-left: 20px;
}

li {
  margin-bottom: 8px;
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover { text-decoration: underline; }

a:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ---- card ---- */

.card {
  background: var(--card);
  border-radius: var(--radius);
  padding: 26px 26px 10px;
  margin: 28px 0;
}

/* ---- signature: the row of noughts ---- */

.days {
  display: flex;
  gap: 10px;
  margin: 40px 0 0;
  flex-wrap: wrap;
}

.day {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  box-shadow: inset 0 0 0 2px var(--accent);
  opacity: 0.9;
}

.day.spent {
  box-shadow: none;
  background: transparent;
  position: relative;
  opacity: 0.5;
}

.day.spent::before,
.day.spent::after {
  content: "";
  position: absolute;
  top: 50%;
  left: 1px;
  right: 1px;
  height: 2px;
  background: #FF9F0A;
  border-radius: 1px;
}

.day.spent::before { transform: rotate(45deg); }
.day.spent::after  { transform: rotate(-45deg); }

.day.pending {
  box-shadow: inset 0 0 0 2px var(--control);
}

/* ---- nav ---- */

nav {
  margin-top: 56px;
  padding-top: 24px;
  border-top: 1px solid var(--control);
  font-size: 15px;
}

nav a { margin-right: 22px; }

footer {
  margin-top: 40px;
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ---- light mode ---- */

@media (prefers-color-scheme: light) {
  :root {
    --bg: #F2F2F7;
    --card: #FFFFFF;
    --control: #E3E3E8;
    --text: #1C1C1E;
    --text-secondary: rgba(60, 60, 67, 0.6);
  }
  h2 { color: #1C7A33; }
  a  { color: #1C7A33; }
  .day.spent::before,
  .day.spent::after { background: #B33000; }
}

@media (max-width: 480px) {
  header { padding-top: 48px; }
  h1 { font-size: 28px; }
  .lede { font-size: 19px; }
}

@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; }
}