body {
  margin: 0;
  font-family: Arial, sans-serif;
  height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Header */
header {
  background: #333;
  color: white;
  padding: 1em;
  text-align: center;
  font-size: 1.5em;
}

/* Main layout (sidebar + iframe) */
#main {
  flex: 1;
  display: flex;
  height: 100%;
}

/* Sidebar */
#sidebar {
  width: 220px;
  background: #f4f4f4;
  border-right: 1px solid #ddd;
  padding: 1em;
  box-sizing: border-box;
  overflow-y: auto;
}
#sidebar ul {
  list-style: none;
  padding: 0;
  margin: 0;
}
#sidebar li {
  margin: 0.5em 0;
}
#sidebar a {
  text-decoration: none;
  color: #333;
  display: block;
  padding: 0.5em;
  border-radius: 4px;
}
#sidebar a:hover {
  background: #ddd;
}
#sidebar a.active {
  background: #333;
  color: white;
  font-weight: bold;
}

/* Content */
#content {
  flex: 1;
  display: flex;
  flex-direction: column;
}

/* Project header */
#project-header {
  padding: 0.75em 1em;
  background: #eee;
  border-bottom: 1px solid #ccc;
  font-size: 1.1em;
}
#project-header a {
  margin-left: 0.2em;
  font-size: 0.8em;
  color: #0066cc;
  text-decoration: none;
}
#project-header a:hover {
  text-decoration: underline;
}

/* Iframe */
#project-frame {
  flex: 1;
  width: 100%;
  border: none;
}