* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Segoe UI', sans-serif;
}

body {
  background: #0f172a;
  color: white;
  transition: background 0.4s, color 0.4s;
}

body.light {
  background: #f9fafb;
  color: #1e293b;
}

/* App Container */
.app {
  max-width: 500px;
  width: 100%;
  margin: 50px auto;
  padding: 24px;
  background: rgba(255, 255, 255, 0.05);
  border-radius: 16px;
  box-shadow: 0 4px 30px rgba(0, 0, 0, 0.2);
  backdrop-filter: blur(10px);
  transition: background 0.3s ease;
}

body.light .app {
  background: rgba(0, 0, 0, 0.03);
}

/* Heading with Typewriter Effect */
.typewriter {
  overflow: hidden;
  white-space: nowrap;
  border-right: 2px solid #38bdf8;
  animation: typing 2.5s steps(40, end), blink 0.75s step-end infinite;
  margin-bottom: 20px;
  text-align: center;
}

@keyframes typing {
  from { width: 0; }
  to { width: 100%; }
}
@keyframes blink {
  50% { border-color: transparent; }
}

/* Input Section */
.input-section {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 20px;
}

.input-section input,
.input-
li button {
  margin-left: 12px;
}