:root {
  --background: #f0f5fa;
  --surface: #ffffff;
  --text: #172b42;
  --muted: #52657a;
  --border: #d8e2ec;
  --link: #005f73;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  font-family: Arial, Helvetica, sans-serif;
  line-height: 1.7;
  background: var(--background);
  color: var(--text);
}

body.dark-mode {
  --background: #101b2b;
  --surface: #1b2c41;
  --text: #eef4fc;
  --muted: #b9c9db;
  --border: #3c5068;
  --link: #7de0d5;
}

a {
  color: var(--link);
}

a:focus-visible,
button:focus-visible {
  outline: 3px solid #eaa400;
  outline-offset: 5px;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 20px;
  padding: 22px 6%;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
}

.brand {
  font-size: 23px;
  font-weight: bold;
  text-decoration: none;
  color: var(--text);
}

nav {
  display: flex;
  gap: 24px;
}

nav a {
  color: var(--muted);
  text-decoration: none;
  font-weight: bold;
}

nav a:hover,
nav a[aria-current="page"] {
  color: var(--link);
  text-decoration: underline;
  text-underline-offset: 6px;
}

#theme-toggle {
  padding: 10px 18px;
  border: 1px solid var(--border);
  border-radius: 24px;
  background: var(--surface);
  color: var(--text);
  font: inherit;
  cursor: pointer;
}

#theme-toggle:hover {
  border-color: var(--link);
}

.container {
  width: min(1100px, 90%);
  margin: 40px auto;
  flex: 1;
}

.hero {
  padding: 60px 48px;
  border-radius: 24px;
  background: linear-gradient(125deg, #153e68, #086f73);
  color: #ffffff;
}

.eyebrow {
  margin: 0 0 14px;
  font-size: 13px;
  font-weight: bold;
  letter-spacing: 3px;
  color: #baf4ed;
}

h1 {
  margin: 0 0 20px;
  font-size: clamp(34px, 5vw, 58px);
  line-height: 1.15;
  letter-spacing: -1px;
}

.hero p:not(.eyebrow) {
  max-width: 650px;
  font-size: 18px;
  color: #e1eef7;
}

.button {
  display: inline-block;
  margin-top: 16px;
  padding: 13px 24px;
  border-radius: 10px;
  background: #086a70;
  color: #ffffff;
  font-weight: bold;
  text-decoration: none;
}

.button:hover {
  background: #064d52;
}

.hero .button {
  background: #ffffff;
  color: #153e68;
}

.hero .button:hover {
  background: #dff4f1;
}

.card {
  margin-top: 28px;
  padding: 30px 36px;
  border: 1px solid var(--border);
  border-radius: 18px;
  background: var(--surface);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.05);
}

h2 {
  margin: 0 0 12px;
  font-size: 26px;
  line-height: 1.3;
}

.card p,
.card li {
  color: var(--muted);
}

.card li {
  margin-bottom: 14px;
}

.card strong {
  color: var(--text);
}

.site-footer {
  padding: 20px;
  text-align: center;
  font-size: 14px;
  color: var(--muted);
  border-top: 1px solid var(--border);
}

@media (max-width: 600px) {
  .site-header {
    justify-content: center;
  }

  .container {
    margin: 24px auto;
  }

  .hero {
    padding: 36px 24px;
  }

  .card {
    padding: 24px;
  }
}