:root {
  --primary: #3b82f6;
  --bg-dark: #020617;
  --card-bg: #0f172a;
  --border-color: #1e293b;
  --text-main: #f1f5f9;
  --text-muted: #94a3b8;
}

* { box-sizing: border-box; -webkit-box-sizing: border-box; }

html, body {
  height: 100%; margin: 0; padding: 0; overflow: hidden;
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background-color: var(--bg-dark);
}

header {
  height: 60px; background: #000; color: white;
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 20px; border-bottom: 1px solid var(--border-color);
}

.main-wrapper {
  display: flex;
  height: calc(100vh - 60px);
  width: 100%;
}

.column {
  display: flex;
  flex-direction: column;
  background: var(--card-bg);
  color: var(--text-main);
  border-right: 1px solid var(--border-color);
  overflow: hidden;
}

.col-left { width: 280px; flex: 0 0 280px; }
.col-center { flex: 1; background: #000; border: none; min-width: 0; }
.col-right { width: 350px; flex: 0 0 350px; border-right: none; border-left: 1px solid var(--border-color); }

.column-header {
  padding: 15px 20px; background: rgba(0,0,0,0.5);
  font-weight: 600; font-size: 0.8rem; text-transform: uppercase;
  color: var(--text-muted); border-bottom: 1px solid var(--border-color);
}

.content-scroll { flex: 1; overflow-y: auto; padding: 10px; }

/* REPRODUCTOR */
.video-viewport {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #000;
  overflow: hidden;
  position: relative;
}

#player { background: #000; display: block; margin: auto; }

.video-info-bar {
  height: 50px; background: #000; display: flex; align-items: center;
  padding: 0 20px; border-top: 1px solid var(--border-color);
}
.video-info-bar h2 { margin: 0; font-size: 1rem; color: #fff; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }

/* ITEMS */
.playlist-item {
  display: block; padding: 12px 15px; color: var(--text-main);
  text-decoration: none; border-radius: 8px; margin-bottom: 5px; font-size: 0.9rem;
}
.playlist-item:hover { background: #1e293b; }
.playlist-item.active { background: var(--primary); color: white; }

.chapter-item {
  display: flex; gap: 10px; padding: 10px; cursor: pointer; border-radius: 8px; margin-bottom: 5px; border: 1px solid transparent;
}
.chapter-item:hover { background: #1e293b; }
.chapter-item.active { background: #1e293b; border-color: var(--primary); }
.chapter-thumb { width: 100px; height: 56px; object-fit: cover; border-radius: 4px; flex-shrink: 0; }
.chapter-details { font-size: 0.8rem; line-height: 1.2; color: var(--text-main); overflow: hidden; }

/* LOGIN */
.auth-container { min-height: 100vh; display: flex; align-items: center; justify-content: center; background: #020617; padding: 20px; }
.login-card { width: 100%; max-width: 420px; background: var(--card-bg); border: 1px solid var(--border-color); border-radius: 20px; padding: 45px; }

::-webkit-scrollbar { width: 4px; }
::-webkit-scrollbar-thumb { background: #334155; border-radius: 10px; }

.btn { cursor: pointer; border-radius: 6px; border: none; padding: 10px; }
.btn-primary { background: #1e293b; color: #3b82f6; }