:root {
  --ink: #24313a;
  --muted: #52616b;
  --accent: #0f766e;
  --accent-light: #d9f0ed;
  --paper: #ffffff;
  --background: #eef4f3;
}

* {
  box-sizing: border-box;
}

body {
  max-width: 900px;
  margin: 0 auto;
  padding: 48px 24px;
  color: var(--ink);
  background: linear-gradient(135deg, var(--background), #f8faf9);
  font-family: Georgia, "Times New Roman", serif;
  line-height: 1.7;
}

h1,
h2,
h3 {
  margin: 0 0 16px;
  color: var(--ink);
  font-family: "Trebuchet MS", Arial, sans-serif;
  line-height: 1.2;
}

h1 {
  padding: 16px 20px;
  border-left: 6px solid var(--accent);
  background: var(--paper);
  box-shadow: 0 4px 14px rgba(36, 49, 58, 0.08);
}

p {
  margin: 0 0 24px;
  padding: 0 4px;
  color: var(--muted);
}

hr {
  margin: 34px 0;
  border: 0;
  border-top: 1px solid #c6d8d5;
}

a {
  color: var(--accent);
  font-weight: bold;
}

a:hover,
a:focus {
  color: #b45309;
}

.browser-image {
  display: block;
  width: min(100%, 600px);
  height: auto;
  margin: 8px auto 28px;
  border: 8px solid var(--paper);
  box-shadow: 0 8px 20px rgba(36, 49, 58, 0.16);
}

.exercise-image {
  max-width: 100%;
  height: auto;
  border: 6px solid var(--paper);
  box-shadow: 0 6px 16px rgba(36, 49, 58, 0.14);
}

.container {
  width: 80%;
  margin: auto;
  overflow: hidden;
}

.header {
  background: var(--ink);
  color: var(--paper);
  padding: 10px 0;
  text-align: center;
}

.footer {
  width: 100%;
  padding: 10px 0;
  background: var(--ink);
  color: var(--paper);
  text-align: center;
}

@media (max-width: 600px) {
  body {
    padding: 24px 16px;
  }

  h1 {
    font-size: 1.7rem;
  }
}