@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@400;500;600;700;800&display=swap');

:root {
  --vst-blue: #2067e7;
  --vst-blue-dark: #174bb3;
  --vst-light-blue: #eaf1ff;
  --ink: #1a2b4a;
  --card-bg: #ffffff;
  --page-bg: #f3f6fc;
  --space: #0b1230;
  --space-2: #131c44;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: 'Poppins', system-ui, sans-serif;
  background: var(--page-bg);
  color: var(--ink);
}

/* ---------- Hero header ---------- */
header.hero {
  background: linear-gradient(160deg, #0b1230 0%, #14204e 60%, #1a2a66 100%);
  color: #fff;
  padding: 2.1rem 1.2rem 1.7rem;
  text-align: center;
}
header.hero .brand {
  font-size: .78rem;
  font-weight: 600;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: #9db8f5;
  margin: 0 0 .45rem;
}
header.hero h1 {
  margin: 0 0 .5rem;
  font-size: clamp(1.5rem, 4vw, 2.1rem);
  font-weight: 800;
}
header.hero p {
  margin: 0 auto;
  max-width: 42rem;
  font-size: .95rem;
  color: #c9d6f5;
}
.gradient-bar {
  height: 6px;
  background: linear-gradient(90deg, #2067e7, #6aa2ff, #ffd76a, #2067e7);
}

/* ---------- Layout ---------- */
main {
  max-width: 62rem;
  margin: 0 auto;
  padding: 1.4rem 1rem 3rem;
}
.card {
  background: var(--card-bg);
  border-radius: 1rem;
  box-shadow: 0 4px 18px rgba(23, 43, 99, .08);
  padding: 1.4rem 1.4rem 1.6rem;
  margin: 0 0 1.4rem;
}
.card-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: .6rem;
  margin: 0 0 .9rem;
}
.card-head h2 { margin: 0; }
.card h2 {
  margin: 0 0 .9rem;
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--vst-blue-dark);
}

/* ---------- Sim ---------- */
.sim-stage {
  background: radial-gradient(120% 140% at 50% 0%, #17235a 0%, var(--space) 65%);
  border-radius: .8rem;
  padding: .4rem;
}
.sim-stage svg { display: block; width: 100%; height: auto; }

.seg-row {
  display: flex;
  justify-content: center;
  gap: .5rem;
  margin: 0 0 .9rem;
}
button.seg {
  font-family: inherit;
  font-size: .88rem;
  font-weight: 600;
  border: 2px solid var(--vst-blue);
  background: #fff;
  color: var(--vst-blue-dark);
  border-radius: 2rem;
  padding: .45rem 1.1rem;
  cursor: pointer;
}
button.seg[aria-pressed="true"] {
  background: var(--vst-blue);
  color: #fff;
}
button.seg:hover { filter: brightness(1.05); }

.scale-flags {
  display: flex;
  justify-content: center;
  gap: .5rem;
  margin: 0 0 .8rem;
  flex-wrap: wrap;
}
.flag {
  font-size: .78rem;
  font-weight: 600;
  border-radius: 2rem;
  padding: .28rem .8rem;
  border: 1px solid;
}
.flag.true { background: #e8f7ee; border-color: #b9e3c8; color: #1b7a3d; }
.flag.false { background: #fff3e0; border-color: #f2ddb4; color: #a2650f; }

.compare-banner {
  margin: .95rem 0 0;
  text-align: center;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--vst-blue-dark);
  background: var(--vst-light-blue);
  border: 1px solid #dbe6ff;
  border-radius: .8rem;
  padding: .8rem 1rem;
}
.compare-banner.counting { color: #6b7ba3; }
.compare-banner.pop {
  animation: bannerPop .45s ease;
  background: #fff8e8;
  border-color: #f2e2b3;
  color: #a2650f;
  font-size: 1.25rem;
}
@keyframes bannerPop {
  0% { transform: scale(.85); }
  55% { transform: scale(1.08); }
  100% { transform: scale(1); }
}
@media (prefers-reduced-motion: reduce) {
  .compare-banner.pop { animation: none; }
}

.chip-group { margin: .9rem 0 0; }
.chip-group .group-label {
  font-size: .75rem;
  font-weight: 600;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: #6b7ba3;
  margin: 0 0 .4rem;
}
.chips {
  display: flex;
  flex-wrap: wrap;
  gap: .45rem;
}
button.chip {
  font-family: inherit;
  font-size: .8rem;
  font-weight: 500;
  border: 1px solid #c9d8f7;
  background: var(--vst-light-blue);
  color: var(--ink);
  border-radius: 2rem;
  padding: .34rem .85rem;
  cursor: pointer;
  transition: background .15s, color .15s;
}
button.chip:hover { background: #dcE8ff; }
button.chip[aria-pressed="true"] {
  background: var(--vst-blue);
  border-color: var(--vst-blue);
  color: #fff;
}

.stat-row {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem;
  margin: .95rem 0 0;
}
.stat {
  flex: 1 1 10rem;
  background: var(--vst-light-blue);
  border: 1px solid #dbe6ff;
  border-radius: .65rem;
  padding: .5rem .8rem;
}
.stat .stat-label {
  font-size: .68rem;
  font-weight: 600;
  letter-spacing: .07em;
  text-transform: uppercase;
  color: #6b7ba3;
}
.stat .stat-value {
  font-size: .95rem;
  font-weight: 700;
  color: var(--vst-blue-dark);
}

.sim-caption {
  margin: .85rem 0 0;
  font-size: .92rem;
  background: #fff8e8;
  border: 1px solid #f2e2b3;
  border-radius: .65rem;
  padding: .6rem .9rem;
}

.textbook-note {
  margin: .85rem 0 0;
  font-size: .88rem;
  color: #5a6a92;
}

/* ---------- Learn more ---------- */
details.learn {
  background: var(--card-bg);
  border-radius: 1rem;
  box-shadow: 0 4px 18px rgba(23, 43, 99, .08);
  margin: 0 0 1.4rem;
  padding: 0;
  overflow: hidden;
}
details.learn > summary {
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  gap: .9rem;
  padding: 1rem 1.2rem;
  background: linear-gradient(160deg, #0b1230 0%, #1a2a66 100%);
  color: #fff;
}
details.learn > summary::-webkit-details-marker { display: none; }
.summary-ball {
  flex: none;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  border: 2px solid #7a3a12;
  background:
    linear-gradient(#7a3a12, #7a3a12) center / 100% 2px no-repeat,
    linear-gradient(#7a3a12, #7a3a12) center / 2px 100% no-repeat,
    #e0762e;
}
.summary-text { flex: 1; display: flex; flex-direction: column; gap: .1rem; }
.summary-title { font-weight: 700; font-size: 1.02rem; }
.summary-sub { font-size: .78rem; color: #9db8f5; }
.summary-cta {
  flex: none;
  background: #ffd76a;
  color: #0b1230;
  font-weight: 700;
  font-size: .78rem;
  border-radius: 2rem;
  padding: .32rem .85rem;
}
details.learn[open] .summary-cta { background: #eaf1ff; }
details.learn[open] > summary .summary-cta::after { content: ' \2212'; }
details.learn:not([open]) > summary .summary-cta::after { content: ' +'; }
details.learn .learn-body { padding: 1.1rem 1.4rem 1.4rem; }
.learn-block { margin: 0 0 1.5rem; }
.learn-block:last-child { margin-bottom: 0; }
.learn-block h3 {
  margin: 0 0 .5rem;
  font-size: .98rem;
  font-weight: 700;
}
.learn-block p { margin: 0 0 .6rem; font-size: .92rem; line-height: 1.55; }


/* ---------- Quiz ---------- */
.quiz-progress {
  font-size: .8rem;
  font-weight: 600;
  color: #6b7ba3;
  margin: 0 0 .6rem;
}
.quiz-q h3 { margin: 0 0 .8rem; font-size: 1rem; }
.quiz-opts { display: grid; gap: .5rem; }
button.opt {
  font-family: inherit;
  text-align: left;
  font-size: .92rem;
  border: 1.5px solid #c9d8f7;
  background: #fff;
  color: var(--ink);
  border-radius: .65rem;
  padding: .62rem .9rem;
  cursor: pointer;
}
button.opt:hover { background: var(--vst-light-blue); }
button.opt[aria-pressed="true"] {
  border-color: var(--vst-blue);
  background: var(--vst-light-blue);
  font-weight: 600;
}
.next-row { margin: .95rem 0 0; text-align: right; }
button.primary {
  font-family: inherit;
  font-size: .9rem;
  font-weight: 600;
  background: var(--vst-blue);
  color: #fff;
  border: none;
  border-radius: 2rem;
  padding: .55rem 1.4rem;
  cursor: pointer;
}
button.primary:disabled { opacity: .4; cursor: default; }
button.primary:hover:not(:disabled) { background: var(--vst-blue-dark); }

.result-card {
  text-align: center;
  background: linear-gradient(160deg, #0b1230, #1a2a66);
  color: #fff;
  border-radius: .9rem;
  padding: 1.6rem 1.2rem;
}
.result-card .big { font-size: 1.4rem; font-weight: 800; margin: .2rem 0 .4rem; }
.result-card .module { color: #9db8f5; font-size: .85rem; }
.result-card .date { color: #ffd76a; font-size: .85rem; font-weight: 600; margin-top: .5rem; }
.result-plain { text-align: center; }
.result-plain .big { font-size: 1.25rem; font-weight: 700; margin: 0 0 .4rem; }
.result-plain p { font-size: .92rem; }

footer.foot {
  text-align: center;
  font-size: .78rem;
  color: #7a89ad;
  padding: 0 1rem 2rem;
}

@media (max-width: 560px) {
  .card { padding: 1.1rem 1rem 1.2rem; }
  button.seg { font-size: .8rem; padding: .4rem .8rem; }
}

.strip-stage { margin: .6rem 0 0; }

.win-wrap { max-width: 440px; margin: .2rem auto 0; }
.win-wrap svg { display: block; width: 100%; height: auto; }