:root {
  --bg: #f4f8ff;
  --card: #ffffff;
  --ink: #1e2a40;
  --accent: #3967ff;
  --accent-dark: #2745ad;
  --muted: #eaf0ff;
  --good: #168f4a;
  --bad: #b32727;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Inter", system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.6;
}

.hero {
  background: linear-gradient(130deg, #dce7ff, #f6f9ff);
  padding: 1rem 1.25rem 3.5rem;
}

.nav {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
}

.logo {
  font-weight: 800;
  font-size: 1.05rem;
}

.nav-links {
  display: flex;
  gap: 1rem;
}

.nav-links a,
footer a {
  color: var(--accent-dark);
  text-decoration: none;
  font-weight: 600;
}

.hero-content {
  max-width: 720px;
  margin: 3rem auto 0;
  text-align: center;
}

.hero h1 {
  font-size: clamp(1.8rem, 4vw, 3rem);
  line-height: 1.15;
  margin: 0 0 0.75rem;
}

.hero p {
  margin: 0 auto 1.5rem;
  max-width: 62ch;
}

.btn {
  border: none;
  background: var(--accent);
  color: white;
  font-weight: 700;
  padding: 0.7rem 1rem;
  border-radius: 0.65rem;
  text-decoration: none;
  display: inline-block;
  cursor: pointer;
}

.btn:hover {
  background: var(--accent-dark);
}

.section {
  max-width: 1100px;
  margin: 0 auto;
  padding: 3rem 1.25rem;
}

.muted {
  background: var(--muted);
  border-radius: 1rem;
}

h2 {
  margin: 0;
  font-size: clamp(1.5rem, 2.5vw, 2rem);
}

.section-subtitle {
  margin-top: 0.5rem;
  margin-bottom: 1.25rem;
  color: #33486f;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 1rem;
}

.card {
  background: var(--card);
  border-radius: 0.9rem;
  padding: 1rem;
  box-shadow: 0 10px 30px rgba(50, 83, 182, 0.08);
}

.card h3 {
  margin-top: 0;
}

.card ul {
  margin: 0.6rem 0 0;
  padding-left: 1.1rem;
}

.practice-box {
  background: var(--card);
  border-radius: 0.9rem;
  padding: 1.2rem;
  max-width: 520px;
  box-shadow: 0 10px 30px rgba(50, 83, 182, 0.08);
}

.practice-box input {
  width: 100%;
  margin: 0.5rem 0 0.75rem;
  padding: 0.65rem;
  border-radius: 0.55rem;
  border: 1px solid #b9c8f2;
  font-size: 1rem;
}

#feedback {
  min-height: 1.25rem;
  margin-top: 0.7rem;
  font-weight: 700;
}

#feedback.good {
  color: var(--good);
}

#feedback.bad {
  color: var(--bad);
}

.roadmap {
  display: grid;
  gap: 0.55rem;
  background: var(--card);
  padding: 1rem;
  border-radius: 0.9rem;
  max-width: 560px;
  box-shadow: 0 10px 30px rgba(50, 83, 182, 0.08);
}

.roadmap label {
  display: flex;
  gap: 0.55rem;
  align-items: flex-start;
}

#progress-text {
  margin-top: 1rem;
  font-weight: 700;
}

footer {
  text-align: center;
  padding: 2rem 1rem 2.5rem;
  color: #2e3f5f;
}