:root {
  --background: #121212;
  --surface: #1e1e1e;
  --surface-light: #2a2a2a;
  --primary: #1db954;
  --text-primary: #ffffff;
  --text-secondary: #b3b3b3;
  --border: #282828;
  --hover: #2a2a2a;
}
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
  background-color: var(--background);
  color: var(--text-primary);
  height: 100vh;
  overflow: hidden;
}
.app {
  display: flex;
  height: calc(100vh - 90px);
}
.sidebar {
  width: 240px;
  background-color: var(--surface);
  padding: 24px;
}
.nav-item {
  display: block;
  padding: 10px;
  color: var(--text-secondary);
  text-decoration: none;
}
.nav-item.active,
.nav-item:hover {
  color: var(--text-primary);
  background: var(--hover);
}
.main-content {
  flex: 1;
  display: flex;
  flex-direction: column;
}
.top-bar {
  padding: 16px;
  background: var(--surface);
}
.content-area {
  flex: 1;
  padding: 24px;
  overflow-y: auto;
}
.page { display: none; }
.page.active { display: block; }
.bottom-player {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  height: 90px;
  background: var(--surface);
  display: flex;
  align-items: center;
  padding: 16px;
  gap: 16px;
}
.progress-bar {
  width: 200px;
  height: 4px;
  background: var(--hover);
}
.progress-fill {
  height: 100%;
  background: var(--primary);
  width: 0%;
}