:root {
  --green: #0b5d3b;
  --green-2: #0f7a4f;
  --ink: #191919;
  --muted: #5f6b77;
  --line: #e5e8ec;
  --bg: #f7f9fb;
  --card: #ffffff;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --green: #4fc28a;
    --green-2: #3aa874;
    --ink: #e8ecef;
    --muted: #a3adb7;
    --line: #2c3238;
    --bg: #121518;
    --card: #1a1e22;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 17px/1.65 -apple-system, "Segoe UI", Roboto, Arial, sans-serif;
}
a { color: var(--green); }
header, main, footer { max-width: 760px; margin: 0 auto; padding: 0 16px; }
header { display: flex; align-items: center; justify-content: space-between; padding-top: 22px; padding-bottom: 22px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; color: var(--ink); text-decoration: none; font-size: 19px; }
.brand img { width: 32px; height: 32px; border-radius: 8px; }
nav a { margin-left: 16px; font-size: 15px; color: var(--muted); text-decoration: none; }
nav a:hover { color: var(--green); }
h1 { font-size: 36px; line-height: 1.2; margin: 18px 0 12px; letter-spacing: -0.4px; }
h2 { font-size: 23px; margin: 36px 0 8px; }
h3 { font-size: 18px; margin: 24px 0 6px; }
p.lede { font-size: 20px; color: var(--muted); margin-top: 0; }
.btn {
  display: inline-block; padding: 12px 22px; border-radius: 999px; background: var(--green); color: #fff;
  text-decoration: none; font-weight: 700; margin: 8px 0 4px;
}
.btn:hover { background: var(--green-2); }
.card { background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 18px 20px; margin: 16px 0; }
.shot { width: 100%; border-radius: 12px; border: 1px solid var(--line); margin: 18px 0; }
code, .formula {
  background: var(--card); border: 1px solid var(--line); border-radius: 8px; padding: 2px 7px; font-size: 15px;
}
.formula { display: block; padding: 12px 16px; font-size: 17px; margin: 12px 0; }
table { width: 100%; border-collapse: collapse; margin: 12px 0; font-size: 16px; }
th, td { text-align: left; padding: 8px 10px; border-bottom: 1px solid var(--line); }
.note { font-size: 14px; color: var(--muted); }
footer { padding-top: 36px; padding-bottom: 40px; color: var(--muted); font-size: 14px; }
@media (max-width: 560px) {
  h1 { font-size: 29px; }
  nav a { margin-left: 10px; }
}

.btn-secondary { background: #fff; color: #0b5d3b; border: 1px solid #0b5d3b; margin-left: 8px; }