:root {
  color-scheme: dark;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: #f4fff7;
  background: #050806;
  font-synthesis: none;
  text-rendering: optimizeLegibility;
  --ink: #f4fff7;
  --muted: #b0c2b5;
  --green: #28d977;
  --green-bright: #5af09a;
  --green-deep: #08763b;
  --line: #203b2b;
  --paper: #0d1711;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-width: 320px;
  line-height: 1.65;
  color: var(--ink);
  background:
    radial-gradient(ellipse at 50% -18%, rgb(23 112 58 / 23%), transparent 48rem),
    #050806;
}

a { color: var(--green-bright); text-underline-offset: 0.2em; }
a:hover { color: #a1ffc3; }

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  max-width: 1120px;
  margin: 0 auto;
  padding: 1.25rem 1.5rem;
  border-bottom: 1px solid rgb(91 171 116 / 12%);
}

.wordmark {
  color: var(--ink);
  font-size: 1.05rem;
  font-weight: 750;
  text-decoration: none;
  letter-spacing: -0.02em;
  transition: color 160ms ease;
}
.wordmark:hover { color: var(--green-bright); }

main { max-width: 1120px; margin: 0 auto; padding: 1rem 1.5rem 4rem; }

.hero { padding: 6rem 0 5rem; max-width: 820px; }

.eyebrow {
  color: var(--green-bright);
  font-size: 0.8rem;
  font-weight: 750;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

h1, h2, h3 { line-height: 1.2; letter-spacing: -0.035em; }
h1 { max-width: 780px; margin: 0.5rem 0 1.25rem; font-size: clamp(2.5rem, 7vw, 4.8rem); }
h2 { font-size: clamp(1.65rem, 3vw, 2.2rem); }
h3 { font-size: 1.18rem; }

.lede { max-width: 720px; color: var(--muted); font-size: 1.2rem; }

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.8rem;
  margin-top: 1rem;
  padding: 0.65rem 1.1rem;
  border: 1px solid var(--green);
  border-radius: 0.55rem;
  background: var(--green-deep);
  color: #fff;
  font: inherit;
  font-weight: 700;
  text-decoration: none;
  cursor: pointer;
  box-shadow: 0 8px 24px rgb(0 0 0 / 22%);
  transition: background 160ms ease, border-color 160ms ease, transform 160ms ease, box-shadow 160ms ease;
}

.button:hover {
  background: #0b9049;
  border-color: var(--green-bright);
  color: #fff;
  box-shadow: 0 10px 28px rgb(18 164 78 / 24%);
  transform: translateY(-1px);
}
.button:focus-visible, a:focus-visible, input:focus-visible, select:focus-visible {
  outline: 3px solid var(--green-bright);
  outline-offset: 3px;
}
.button:disabled { opacity: 0.65; cursor: wait; }
.button-quiet {
  margin-top: 0;
  background: rgb(18 36 24 / 68%);
  color: var(--ink);
  border: 1px solid #31563c;
  box-shadow: none;
}
.button-quiet:hover { background: #14271a; color: #fff; }

.section { padding: 2.5rem 0; }
.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 1rem; }
.card, .note, .access-card {
  padding: 1.35rem;
  border: 1px solid var(--line);
  border-radius: 0.9rem;
  background:
    linear-gradient(145deg, rgb(19 39 25 / 78%), rgb(11 20 14 / 96%) 65%),
    var(--paper);
  box-shadow: 0 18px 55px rgb(0 0 0 / 24%);
}
.card { transition: border-color 180ms ease, transform 180ms ease; }
.card:hover { border-color: #39754b; transform: translateY(-3px); }
.card p, .note p { color: var(--muted); }
.card h3, .note h2 { color: #fff; }
.price { color: #fff; font-size: 1.7rem; font-weight: 750; }
.price span { display: block; color: var(--muted); font-size: 0.8rem; font-weight: 500; }
.currency-choice { max-width: 430px; }
.currency-choice label { margin-top: 0; }
select {
  width: 100%;
  min-height: 3rem;
  margin-top: 0.45rem;
  padding: 0.65rem;
  border: 1px solid #31563c;
  border-radius: 0.45rem;
  background: #0b120d;
  color: #fff;
  font: inherit;
}
.note { max-width: 800px; }
.closing { padding-top: 2rem; }

.access-wrap { display: grid; min-height: 70vh; place-items: center; }
.access-card { width: min(100%, 560px); padding: clamp(1.5rem, 5vw, 2.5rem); }
.access-card h1, .course-wrap h1 { font-size: clamp(2.2rem, 6vw, 3.3rem); }
label { display: block; margin-top: 1.5rem; font-weight: 700; }
input {
  width: 100%;
  min-height: 3rem;
  margin-top: 0.45rem;
  padding: 0.7rem;
  border: 1px solid #31563c;
  border-radius: 0.45rem;
  background: #080e0a;
  color: #fff;
  font: inherit;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  letter-spacing: 0.04em;
}
.status { min-height: 1.65em; color: #ffb0a8; }
.small { font-size: 0.9rem; }

.course-wrap { max-width: 850px; padding-top: 3rem; }
.lesson-list { padding-left: 1.5rem; }
.lesson-list li { margin: 0.8rem 0; padding-left: 0.3rem; }
.lesson-list a { font-weight: 650; }

.lesson-body { max-width: 1000px; }
.lesson-body pre {
  overflow-x: auto;
  padding: 1.5rem;
  border: 1px solid var(--line);
  border-radius: 0.75rem;
  background: #090f0b;
  color: #f3fff6;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
  font: 0.95rem/1.7 ui-monospace, SFMono-Regular, Menlo, monospace;
}
.lesson-body pre code { padding: 0; background: none; color: inherit; font: inherit; }
.lesson-body code {
  padding: 0.1rem 0.3rem;
  border-radius: 0.3rem;
  background: rgba(127, 127, 127, 0.15);
  font: 0.92em ui-monospace, SFMono-Regular, Menlo, monospace;
}
.lesson-body li { margin: 0.4rem 0; }
.lesson-body blockquote {
  margin: 1.5rem 0;
  padding-left: 1rem;
  border-left: 3px solid var(--line);
}
.lesson-body .table-wrap { overflow-x: auto; margin: 1.5rem 0; }
.lesson-body table { width: 100%; border-collapse: collapse; }
.lesson-body th, .lesson-body td {
  padding: 0.6rem 0.8rem;
  border: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

.quiz-page form, .simulation-card {
  display: grid;
  gap: 1rem;
}
.quiz-page fieldset, .simulation-card {
  padding: 1.2rem;
  border: 1px solid var(--line);
  border-radius: 0.75rem;
  background: linear-gradient(145deg, rgb(19 39 25 / 78%), rgb(11 20 14 / 96%) 65%);
}
.quiz-page legend, .simulation-card h2 {
  padding: 0 0.35rem;
  font-size: 1.1rem;
  font-weight: 700;
}
.quiz-page fieldset label, .simulation-choices label {
  display: flex;
  align-items: flex-start;
  gap: 0.65rem;
  margin: 0.85rem 0;
  color: var(--muted);
  cursor: pointer;
  font-weight: 500;
}
.quiz-page input[type="radio"], .simulation-card input[type="radio"] {
  width: auto;
  min-height: 1.2rem;
  margin: 0.25rem 0 0;
  accent-color: var(--green-bright);
}
.quiz-page fieldset[aria-invalid="true"] { border-color: #b87168; }
.quiz-feedback, .simulation-feedback, .simulation-result, .quiz-result {
  padding: 0.8rem 1rem;
  border-left: 3px solid var(--green-bright);
  background: rgb(31 73 43 / 35%);
  color: var(--ink);
}
.simulation-card { margin: 1.5rem 0; }
.simulation-card .eyebrow { margin-top: 0; }
.simulation-choices { margin: 1rem 0; }
.simulation-card [hidden], .quiz-page [hidden] { display: none; }

footer {
  border-top: 1px solid rgb(91 171 116 / 16%);
  padding: 1.5rem;
  color: var(--muted);
  text-align: center;
  font-size: 0.9rem;
}

@media (max-width: 700px) {
  .hero { padding: 3.5rem 0; }
  .cards { grid-template-columns: 1fr; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
  }
}