:root {
  --primary: #4a90e2;
  --accent: #48bb78;
  --danger: #e53e3e;
  --bg-gradient: linear-gradient(135deg, #4a90e2, #6b46c1);
}

body {
  font-family: 'Segoe UI', sans-serif;
  background: var(--bg-gradient);
  color: #fff;
  margin: 0;
  padding: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
}

.main-container {
  display: flex;
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(20px);
  border-radius: 20px;
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.3);
  overflow: hidden;
  width: 90%;
  max-width: 1000px;
  height: 90vh;
}

.left-panel, .right-panel {
  padding: 30px;
  overflow-y: auto;
}

.left-panel { width: 65%; }
.right-panel {
  width: 35%;
  background: rgba(0,0,0,0.2);
  border-left: 1px solid rgba(255,255,255,0.1);
  text-align: center;
}

.btn {
  border: none;
  padding: 10px 14px;
  border-radius: 8px;
  cursor: pointer;
  font-weight: bold;
  margin: 5px;
  transition: 0.3s;
}

.btn.upload { background: var(--accent); color: #fff; }
.btn.clear { background: var(--danger); color: #fff; }
.btn.join { background: var(--primary); color: #fff; }
.btn.copy { background: #ffd166; color: #000; }

.btn:hover { transform: scale(1.05); opacity: 0.9; }

.progress-container {
  background: rgba(255,255,255,0.2);
  border-radius: 8px;
  overflow: hidden;
  margin: 10px 0;
  height: 10px;
}

#progressBar {
  width: 0%;
  height: 10px;
  background: var(--accent);
  transition: width 0.2s ease;
}

.toast {
  position: fixed;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  background: #48bb78;
  color: white;
  padding: 10px 20px;
  border-radius: 20px;
  display: none;
  font-weight: bold;
}

.file-list li {
  background: rgba(255,255,255,0.15);
  padding: 8px 12px;
  border-radius: 8px;
  margin-bottom: 6px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.sender-tag {
  background: rgba(0,0,0,0.3);
  padding: 3px 8px;
  border-radius: 6px;
  font-size: 0.8rem;
  margin-left: 10px;
  opacity: 0.8;
}