* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  background:
    radial-gradient(circle at top, #071633 0%, #020814 70%);
  color: white;
  font-family: Arial, sans-serif;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  padding: 20px;
}

.app {
  width: 100%;
  max-width: 430px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.header {
  display: flex;
  align-items: center;
  gap: 14px;
}

.logo {
  width: 74px;
  height: 74px;
  border-radius: 18px;
  object-fit: cover;
  box-shadow:
    0 0 20px rgba(0,255,255,0.35);
}

.title-box h1 {
  font-size: 28px;
  color: #dfe8ff;
}

.title-box p {
  color: #7fdfff;
  margin-top: 4px;
}

.chat-box {
  height: 62vh;
  overflow-y: auto;
  background: rgba(0,0,0,0.28);
  border: 1px solid rgba(0,255,255,0.12);
  border-radius: 28px;
  padding: 18px;
  display: flex;
  flex-direction: column;
  gap: 14px;
  box-shadow:
    inset 0 0 25px rgba(0,100,255,0.15),
    0 0 20px rgba(0,100,255,0.08);
}

.message {
  max-width: 82%;
  padding: 14px 16px;
  border-radius: 22px;
  line-height: 1.5;
  word-wrap: break-word;
}

.user {
  align-self: flex-end;
  background:
    linear-gradient(135deg, #2563ff, #3b82f6);
  color: white;
  border-bottom-right-radius: 8px;
}

.bot {
  align-self: flex-start;
  background:
    rgba(255,255,255,0.08);
  border: 1px solid rgba(255,255,255,0.05);
  color: #e8f0ff;
  border-bottom-left-radius: 8px;
}

.input-area {
  display: flex;
  gap: 12px;
}

#userInput {
  flex: 1;
  background: rgba(0,0,0,0.35);
  border: 1px solid rgba(0,255,255,0.18);
  color: white;
  padding: 16px;
  border-radius: 18px;
  outline: none;
  font-size: 16px;
}

#userInput::placeholder {
  color: rgba(255,255,255,0.45);
}

#sendBtn {
  background:
    linear-gradient(135deg, #2563ff, #3b82f6);
  color: white;
  border: none;
  padding: 0 22px;
  border-radius: 18px;
  font-size: 16px;
  font-weight: bold;
  cursor: pointer;
  box-shadow:
    0 0 18px rgba(59,130,246,0.4);
}

#sendBtn:active {
  transform: scale(0.97);
}