:root {
  --ink: #183338;
  --muted: #66777a;
  --line: #d9dfdc;
  --paper: #f7f3e8;
  --card: #fffdf8;
  --teal: #0f4a4e;
  --teal-dark: #0a383b;
  --amber: #d29a42;
  --green: #19724e;
  --green-bg: #e8f6ee;
  --red: #a83d38;
  --red-bg: #fff0ee;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--ink);
  background: var(--paper);
  font-synthesis: none;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; min-width: 320px; min-height: 100vh; background: var(--paper); }
button { font: inherit; }
button:focus-visible { outline: 3px solid rgba(210, 154, 66, .45); outline-offset: 2px; }
svg { width: 1.15rem; height: 1.15rem; }

.site-header { border-bottom: 1px solid rgba(217, 223, 220, .9); background: rgba(255, 253, 248, .92); backdrop-filter: blur(12px); }
.header-inner { max-width: 1120px; margin: 0 auto; padding: 1rem 1.5rem; display: flex; align-items: center; justify-content: space-between; gap: 1rem; }
.brand { display: flex; align-items: center; gap: .75rem; }
.brand-icon { width: 2.55rem; height: 2.55rem; display: grid; place-items: center; border-radius: .8rem; color: white; background: var(--teal); }
.brand strong, .brand small { display: block; }
.brand strong { max-width: 430px; font-size: .86rem; line-height: 1.25; }
.brand small { margin-top: .15rem; color: var(--muted); font-size: .74rem; }
.attempt-pill { border: 1px solid rgba(15, 74, 78, .16); background: rgba(15, 74, 78, .06); color: var(--teal); padding: .45rem .75rem; border-radius: 999px; font-size: .75rem; font-weight: 750; white-space: nowrap; }

.intro-shell { position: relative; max-width: 1120px; min-height: calc(100vh - 74px); margin: 0 auto; padding: 5.5rem 1.5rem; display: grid; grid-template-columns: minmax(0, 1fr) 340px; align-items: center; gap: 3rem; }
.intro-shell::before { content: ""; position: fixed; inset: 74px 0 auto; height: 440px; z-index: -1; background: radial-gradient(circle at 20% 20%, rgba(210,154,66,.17), transparent 34%), radial-gradient(circle at 78% 5%, rgba(15,74,78,.14), transparent 33%); }
.eyebrow, .topic, .score-eyebrow { color: #95651d; text-transform: uppercase; letter-spacing: .14em; font-size: .73rem; font-weight: 800; }
.eyebrow { width: fit-content; display: flex; align-items: center; gap: .5rem; padding: .48rem .72rem; border-radius: 999px; border: 1px solid rgba(210,154,66,.32); background: rgba(210,154,66,.1); }
.intro-copy h1 { max-width: 760px; margin: 1.2rem 0 0; font-size: clamp(2.5rem, 5.3vw, 4rem); line-height: 1.06; letter-spacing: -.04em; }
.lead { max-width: 720px; margin: 1.5rem 0 0; color: var(--muted); font-size: 1.08rem; line-height: 1.8; }
.intro-actions { margin-top: 2rem; display: flex; flex-wrap: wrap; align-items: center; gap: 1rem; }
.intro-actions > span { color: var(--muted); display: flex; align-items: center; gap: .45rem; font-size: .86rem; }

.primary-button, .secondary-button { min-height: 2.85rem; border-radius: .78rem; border: 0; padding: .7rem 1.1rem; display: inline-flex; align-items: center; justify-content: center; gap: .55rem; cursor: pointer; font-weight: 750; transition: transform .15s ease, background .15s ease, opacity .15s ease; }
.primary-button { background: var(--teal); color: white; }
.primary-button:hover { background: var(--teal-dark); transform: translateY(-1px); }
.secondary-button { background: transparent; color: var(--ink); border: 1px solid var(--line); }
.secondary-button:hover { background: #f4f4ef; }
.secondary-button:disabled { opacity: .4; cursor: not-allowed; }

.how-card, .random-card { background: var(--teal); color: white; border-radius: 1.6rem; padding: 2rem; box-shadow: 0 28px 80px -40px rgba(10,56,59,.9); }
.how-icon { color: var(--amber); }
.how-icon svg { width: 2rem; height: 2rem; }
.how-card h2 { margin: 1.5rem 0 0; font-size: 1.5rem; }
.how-card ol { list-style: none; padding: 0; margin: 1.5rem 0 0; display: grid; gap: 1.25rem; }
.how-card li { display: flex; align-items: flex-start; gap: .8rem; color: rgba(255,255,255,.77); font-size: .88rem; line-height: 1.6; }
.how-card li b { width: 1.75rem; height: 1.75rem; flex: 0 0 auto; display: grid; place-items: center; border-radius: 999px; background: rgba(255,255,255,.1); color: var(--amber); }
.fine-print { margin: 1.55rem 0 0; padding-top: 1.25rem; border-top: 1px solid rgba(255,255,255,.15); color: rgba(255,255,255,.58); font-size: .72rem; line-height: 1.65; }

.quiz-shell { max-width: 1120px; margin: 0 auto; padding: 2.8rem 1.5rem; display: grid; grid-template-columns: minmax(0, 1fr) 280px; align-items: start; gap: 2rem; }
.question-card, .review-card { background: var(--card); border: 1px solid var(--line); border-radius: 1.6rem; }
.question-card { padding: 2.25rem; box-shadow: 0 22px 70px -40px rgba(15,47,52,.45); }
.progress-row { display: flex; justify-content: space-between; gap: 1rem; font-size: .82rem; }
.progress-row span { color: var(--muted); }
.progress-track { margin-top: .65rem; height: .48rem; overflow: hidden; border-radius: 999px; background: #e7e7df; }
.progress-track span { display: block; height: 100%; border-radius: inherit; background: var(--teal); transition: width .25s ease; }
.question-card .topic { margin-top: 2rem; }
.question-card h1 { margin: .75rem 0 0; max-width: 800px; font-size: clamp(1.45rem, 2.8vw, 2rem); line-height: 1.35; letter-spacing: -.02em; }
.instruction { margin: .7rem 0 0; color: var(--muted); font-size: .88rem; }
.options { display: grid; gap: .75rem; margin-top: 1.7rem; }
.option { width: 100%; min-height: 3.6rem; padding: .75rem 1rem; border: 1px solid var(--line); border-radius: 1rem; background: var(--paper); color: var(--ink); display: flex; align-items: center; gap: .9rem; text-align: left; cursor: pointer; transition: border .15s ease, background .15s ease, transform .15s ease; }
.option:hover { border-color: rgba(15,74,78,.42); background: rgba(15,74,78,.035); transform: translateY(-1px); }
.option.selected { border-color: var(--teal); background: rgba(15,74,78,.08); color: var(--teal); box-shadow: 0 4px 14px rgba(15,74,78,.08); }
.option-label { width: 1.8rem; height: 1.8rem; flex: 0 0 auto; display: grid; place-items: center; border: 1px solid var(--line); border-radius: .5rem; background: var(--card); color: var(--muted); font-size: .74rem; font-weight: 800; }
.selected .option-label { border-color: var(--teal); background: var(--teal); color: white; }
.warning { color: var(--red); display: flex; align-items: center; gap: .45rem; font-size: .82rem; font-weight: 700; }
.nav-row { margin-top: 2rem; display: flex; justify-content: space-between; gap: .75rem; }
.quiz-aside { display: grid; gap: 1rem; }
.random-card { padding: 1.5rem; }
.random-card > svg { color: var(--amber); width: 1.5rem; height: 1.5rem; }
.random-card h2 { margin: 1.15rem 0 0; font-size: 1.1rem; }
.random-card p { margin: .65rem 0 0; color: rgba(255,255,255,.7); font-size: .82rem; line-height: 1.65; }
.status-card { background: var(--card); border: 1px solid var(--line); border-radius: 1rem; padding: 1rem; display: flex; align-items: center; gap: .7rem; color: var(--muted); font-size: .82rem; }
.status-card svg { color: #95651d; }

.results-shell { max-width: 960px; margin: 0 auto; padding: 3rem 1.5rem 5rem; }
.score-card { padding: 2.5rem; border-radius: 1.6rem 1.6rem 0 0; background: var(--teal); color: white; display: grid; grid-template-columns: 1fr auto; align-items: end; gap: 2rem; }
.score-card h1 { margin: .7rem 0 0; font-size: clamp(2rem, 5vw, 2.8rem); }
.score-card p:last-child { max-width: 620px; color: rgba(255,255,255,.68); font-size: .87rem; line-height: 1.65; }
.score-number { padding: 1.1rem 1.4rem; border-radius: 1rem; background: rgba(255,255,255,.1); display: flex; align-items: baseline; gap: .45rem; white-space: nowrap; }
.score-number strong { color: var(--amber); font-size: 3.3rem; }
.score-number span { color: rgba(255,255,255,.65); font-size: 1.25rem; }
.score-number b { margin-left: .45rem; }
.score-actions { padding: 1.4rem 2rem; border: 1px solid var(--line); border-top: 0; border-radius: 0 0 1.6rem 1.6rem; background: var(--card); display: flex; align-items: center; justify-content: space-between; gap: 1rem; }
.score-actions p { color: var(--muted); font-size: .85rem; }
.review { margin-top: 2.5rem; }
.review > h2 { margin: .4rem 0 1.2rem; font-size: 1.65rem; }
.review-card { padding: 1.5rem; margin-top: 1rem; }
.review-title { display: flex; align-items: flex-start; gap: .75rem; }
.review-title p { margin: 0; color: var(--muted); text-transform: uppercase; letter-spacing: .1em; font-size: .68rem; font-weight: 800; }
.review-title h3 { margin: .5rem 0 0; line-height: 1.5; font-size: 1.05rem; }
.result-icon { width: 2rem; height: 2rem; flex: 0 0 auto; display: grid; place-items: center; border-radius: 999px; }
.result-icon.right { background: var(--green-bg); color: var(--green); }
.result-icon.wrong { background: var(--red-bg); color: var(--red); }
.answer-comparison { margin: 1.35rem 0 0 2.75rem; display: grid; grid-template-columns: 1fr 1fr; gap: .85rem; }
.comparison-column { min-width: 0; padding: 1rem; border: 1px solid var(--line); border-radius: 1rem; background: var(--paper); }
.comparison-column h4 { margin: 0; font-size: .88rem; }
.student-answers h4 { color: var(--teal); }
.correct-answers h4 { color: var(--green); }
.comparison-note { margin: .3rem 0 0; color: var(--muted); font-size: .68rem; line-height: 1.45; }
.comparison-list { display: grid; gap: .55rem; margin-top: .85rem; }
.comparison-answer { min-width: 0; padding: .68rem .72rem; border: 1px solid var(--line); border-radius: .72rem; display: grid; grid-template-columns: 1.45rem minmax(0, 1fr); gap: .25rem .65rem; align-items: start; font-size: .77rem; }
.comparison-label { width: 1.45rem; height: 1.45rem; display: grid; place-items: center; border: 1px solid currentColor; border-radius: .4rem; font-size: .64rem; font-weight: 800; }
.comparison-answer p { min-width: 0; margin: 0; line-height: 1.55; }
.comparison-answer b { grid-column: 2; width: fit-content; font-size: .64rem; }
.student-correct, .expected-answer { border-color: #acd8bf; background: var(--green-bg); color: #15583e; }
.student-wrong { border-color: #efb8b3; background: var(--red-bg); color: #84312d; }
.bottom-action { margin-top: 2rem; display: flex; justify-content: center; }
.creator-footer { max-width: 1120px; margin: 0 auto; padding: 1.5rem 1rem 2rem; border-top: 1px solid rgba(217,223,220,.8); color: var(--muted); text-align: center; font-size: .68rem; letter-spacing: .015em; }
.creator-footer a { color: var(--teal); text-decoration: none; }
.creator-footer a:hover { text-decoration: underline; }

@media (max-width: 860px) {
  .intro-shell, .quiz-shell { grid-template-columns: 1fr; }
  .intro-shell { padding-top: 3rem; }
  .quiz-aside { grid-template-columns: 1fr 1fr; }
  .random-card { grid-column: 1 / -1; }
}

@media (max-width: 620px) {
  .header-inner { padding-inline: 1rem; }
  .brand strong { max-width: 215px; font-size: .72rem; }
  .brand small { font-size: .65rem; }
  .intro-shell, .quiz-shell, .results-shell { padding-left: 1rem; padding-right: 1rem; }
  .question-card { padding: 1.25rem; border-radius: 1.25rem; }
  .nav-row { align-items: stretch; }
  .nav-row button { padding-inline: .75rem; }
  .quiz-aside { grid-template-columns: 1fr; }
  .random-card { grid-column: auto; }
  .score-card { grid-template-columns: 1fr; padding: 1.5rem; }
  .score-number { width: fit-content; }
  .score-actions { align-items: stretch; flex-direction: column; padding: 1.25rem; }
  .review-card { padding: 1.1rem; }
  .answer-comparison { margin-left: 0; grid-template-columns: 1fr; }
}