:root {
  --bg-color: #fdfdfd;
  --text-color: #222;
  --header-bg: #fefefe;
  --footer-bg: #fefefe;
  --link-color: #333;
  --btn-bg: #ccc;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: system-ui, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-color);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  text-align: center;
  transition: background-color 0.3s, color 0.3s;
}

header {
  background-color: var(--header-bg);
  padding: 20px;
  position: relative;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

header h1 {
  font-size: 2.5em;
  margin-bottom: 5px;
}

nav {
  margin-top: 10px;
}

nav a {
  margin: 0 10px;
  color: var(--link-color);
  text-decoration: none;
  font-weight: 500;
}

nav a:hover {
  text-decoration: underline;
}

main {
  flex: 1;
  padding: 40px 20px;
  display: flex;
  flex-direction: column;
  align-items: center;
}

iframe {
  margin: 20px 0;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.08);
  border-radius: 8px;
}

.clocks {
  display: flex;
  gap: 20px;
  margin-top: 20px;
  flex-wrap: wrap;
  justify-content: center;
}

footer {
  background-color: var(--footer-bg);
  padding: 15px;
  font-size: 0.9em;
  color: var(--text-color);
  box-shadow: 0 -1px 3px rgba(0, 0, 0, 0.05);
}