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

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Inter", "Segoe UI", sans-serif;
  background: #f0f4ff;
  color: #2c2f45;
}

/* ── Navigation ── */
nav {
  background: #ffffff;
  border-bottom: 1px solid #dde3f5;
  padding: 12px 24px;
  display: flex;
  justify-content: center;
  gap: 8px;
  flex-wrap: wrap;
  position: sticky;
  top: 0;
  z-index: 100;
}

nav a {
  text-decoration: none;
  color: #4a5ac7;
  font-weight: 500;
  font-size: 14px;
  padding: 7px 18px;
  border-radius: 30px;
  background: #f0f2ff;
  border: 1px solid #d0d5f0;
  transition: background 0.2s, color 0.2s, border-color 0.2s;
  white-space: nowrap;
}

nav a:hover {
  background: #e0e5ff;
  border-color: #b0baee;
  color: #3347c0;
}

nav a.active {
  background: #4a5ac7;
  color: #ffffff;
  border-color: #4a5ac7;
}

/* ── Header ── */
header {
  text-align: center;
  padding: 48px 20px 32px;
  background: linear-gradient(135deg, #dce8ff 0%, #ede4ff 100%);
  border-bottom: 1px solid #d0d8f5;
}

header h1 {
  margin: 0;
  font-size: 30px;
  font-weight: 600;
  color: #2a3499;
  letter-spacing: 0.3px;
}

.subtitle {
  margin-top: 10px;
  font-size: 15px;
  color: #5a66b0;
}

/* ── Main content ── */
main {
  max-width: 880px;
  margin: 32px auto;
  padding: 0 16px;
}

/* ── Sections ── */
section {
  background: #ffffff;
  border: 1px solid #dde3f5;
  border-radius: 16px;
  padding: 24px 28px;
  margin-bottom: 20px;
  transition: box-shadow 0.2s, transform 0.2s;
}

section:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(74, 90, 199, 0.1);
}

h2 {
  margin-top: 0;
  font-size: 18px;
  font-weight: 600;
  color: #3347c0;
}

p {
  line-height: 1.7;
  color: #3a3f5c;
  margin: 0 0 12px;
}

p:last-child {
  margin-bottom: 0;
}

/* ── Images ── */
img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 12px;
  margin-top: 16px;
  border: 1px solid #dde3f5;
}

/* ── Lists ── */
ul {
  padding-left: 20px;
  color: #3a3f5c;
}

li {
  margin-bottom: 8px;
  line-height: 1.6;
}

/* ── Summary block ── */
.summary {
  background: #fff8ec;
  border: 1px solid #fce4b0;
  border-left: 5px solid #f5a623;
  border-radius: 12px;
}

.summary h2 {
  color: #b36c00;
}

/* ── Footer ── */
footer {
  text-align: center;
  padding: 24px;
  color: #8892c0;
  font-size: 13px;
  border-top: 1px solid #dde3f5;
  margin-top: 16px;
}