body {
  font-family: -apple-system,BlinkMacSystemFont,"SF Pro Text","Segoe UI",Roboto,"Helvetica Neue",Arial;
  background: #f5f5f7;
  color: #1d1d1f;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}
.nav {
  text-align: center;
  padding: 12px;
  font-weight: 600;
  font-size: 17px;
  background: rgba(255,255,255,0.9);
  border-bottom: 1px solid #e5e5ea;
  backdrop-filter: blur(20px);
  position: sticky;
  top: 0;
}
.container {
  flex: 1;
  width: 94%;
  max-width: 440px;
  margin: 20px auto;
  background: #fff;
  border-radius: 14px;
  box-shadow: 0 4px 10px rgba(0,0,0,0.05);
  padding: 18px;
}
textarea {
  width: 100%;
  min-height: 160px;
  border: 1px solid #ccc;
  border-radius: 10px;
  padding: 10px;
  font-size: 15px;
  resize: vertical;
  outline: none;
}
textarea:focus {
  border-color: #0071e3;
  box-shadow: 0 0 0 3px rgba(0,113,227,.15);
}
.btn-group {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 12px;
}
button {
  flex: 1;
  border: none;
  border-radius: 12px;
  padding: 12px;
  font-size: 15px;
  font-weight: 600;
  color: #fff;
  cursor: pointer;
  transition: 0.2s;
}
.btn-primary { background: #0071e3; }
.btn-blue { background: #007aff; }
.btn-green { background: #34c759; }
.btn-clear { background: #ff3b30; }
button:active {
  transform: scale(0.97);
}
#toast {
  position: fixed;
  bottom: 80px;
  left: 50%;
  transform: translateX(-50%);
  background: rgba(0,0,0,0.85);
  color: #fff;
  padding: 12px 22px;
  border-radius: 30px;
  font-size: 15px;
  opacity: 0;
  z-index: 9999;
  transition: opacity .25s ease-in-out;
  pointer-events: none;
}
pre {
  white-space: pre-wrap;
  word-break: break-all;
  background: #f8f9fa;
  padding: 10px;
  border-radius: 8px;
  border: 1px solid #ddd;
  margin-top: 10px;
  font-size: 14px;
}