:root {
  color-scheme: light;
  --ink: #152229;
  --muted: #64727a;
  --line: #d9e2e4;
  --paper: #f6f8f8;
  --panel: #ffffff;
  --steel: #315f74;
  --teal: #287c70;
  --safety: #d45b42;
  --gold: #b98422;
  --shadow: 0 18px 55px rgba(21, 34, 41, 0.14);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: Inter, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

button,
select {
  font: inherit;
}

button {
  cursor: pointer;
}

.hero {
  position: relative;
  min-height: 46vh;
  display: grid;
  align-items: end;
  overflow: hidden;
}

.hero img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(90deg, rgba(10, 18, 22, 0.82), rgba(10, 18, 22, 0.36) 52%, rgba(10, 18, 22, 0.08));
}

.hero-content {
  position: relative;
  z-index: 1;
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
  padding: 44px 0;
  color: #fff;
}

.eyebrow {
  margin: 0 0 7px;
  color: #76d0c4;
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin: 0;
}

h1 {
  max-width: 760px;
  font-size: clamp(2.3rem, 6vw, 5.4rem);
  line-height: 0.92;
  letter-spacing: 0;
}

.hero-content p:last-child {
  max-width: 650px;
  margin-top: 16px;
  color: rgba(255, 255, 255, 0.86);
  font-size: 1.08rem;
  line-height: 1.55;
}

.app-shell {
  width: min(1120px, calc(100% - 32px));
  margin: -22px auto 34px;
  position: relative;
  z-index: 2;
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 16px;
}

.sidebar,
.learning-panel,
.lesson-card,
.diagnostic {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.94);
  box-shadow: var(--shadow);
}

.sidebar {
  align-self: start;
  padding: 14px;
}

.progress {
  display: grid;
  gap: 7px;
  padding: 10px 10px 16px;
}

.progress span {
  font-size: 2rem;
  font-weight: 800;
}

.progress small {
  color: var(--muted);
  font-weight: 700;
}

.meter {
  height: 9px;
  overflow: hidden;
  border-radius: 999px;
  background: #e8eef0;
}

.meter i {
  display: block;
  width: 0%;
  height: 100%;
  border-radius: inherit;
  background: var(--teal);
  transition: width 180ms ease;
}

.lesson-nav {
  display: grid;
  gap: 8px;
}

.lesson-nav button {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  color: var(--ink);
  padding: 12px;
  text-align: left;
  font-weight: 800;
}

.lesson-nav button.active {
  border-color: var(--steel);
  background: #eaf2f5;
}

.lesson-nav button.done::after {
  content: "Complete";
  display: block;
  margin-top: 4px;
  color: var(--teal);
  font-size: 0.74rem;
}

.learning-panel {
  padding: 18px;
}

.toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 16px;
}

h2 {
  font-size: clamp(1.6rem, 4vw, 2.7rem);
  line-height: 1;
  letter-spacing: 0;
}

.toolbar button {
  border: 0;
  border-radius: 8px;
  background: var(--teal);
  color: #fff;
  padding: 12px 14px;
  font-weight: 800;
  white-space: nowrap;
}

.lesson-grid,
.trainer-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.trainer-grid {
  margin-top: 14px;
}

.lesson-card,
.diagnostic {
  box-shadow: none;
  padding: 16px;
}

h3 {
  margin-bottom: 12px;
  font-size: 1.02rem;
}

ul,
ol {
  margin: 0;
  padding-left: 20px;
  color: var(--muted);
  line-height: 1.55;
}

li + li {
  margin-top: 8px;
}

label {
  display: grid;
  gap: 8px;
  color: var(--muted);
  font-size: 0.82rem;
  font-weight: 800;
}

select {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  color: var(--ink);
  padding: 11px 12px;
}

.result,
.feedback {
  margin-top: 12px;
  border-radius: 8px;
  background: #eef5f4;
  padding: 13px;
  color: #24433e;
  line-height: 1.45;
}

.result strong {
  display: block;
  margin-bottom: 6px;
  color: var(--ink);
}

.choice-list {
  display: grid;
  gap: 8px;
  margin-top: 12px;
}

.choice-list button {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  padding: 11px;
  color: var(--ink);
  text-align: left;
  font-weight: 700;
}

.choice-list button:hover {
  border-color: var(--steel);
}

.feedback.correct {
  background: #e9f5ee;
  color: #235c3a;
}

.feedback.miss {
  background: #fff0ec;
  color: #8b3828;
}

@media (max-width: 900px) {
  .hero {
    min-height: 54vh;
  }

  .app-shell,
  .lesson-grid,
  .trainer-grid {
    grid-template-columns: 1fr;
  }

  .app-shell {
    margin-top: 16px;
  }
}

@media (max-width: 560px) {
  .hero-content,
  .app-shell {
    width: min(100% - 22px, 1120px);
  }

  .toolbar {
    align-items: stretch;
    flex-direction: column;
  }

  .toolbar button {
    width: 100%;
  }
}