:root {
  --bg1: #020617;
  --bg2: #0f172a;
  --panel: #020617cc;
  --neon: #38bdf8;
  --text: #e5e7eb;
  --muted: #9ca3af;
  --accent: #0ea5e9;
  --border: #1e293b;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 0;
  font-family: Inter, system-ui, sans-serif;
  background: linear-gradient(120deg, var(--bg1), var(--bg2), var(--bg1));
  background-size: 300% 300%;
  animation: bgMove 18s ease infinite;
  color: var(--text);
  height: 100vh;
  display: flex;
  flex-direction: column;
}

@keyframes bgMove {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

header {
  background: linear-gradient(90deg, #020617, #020617, #0f172a);
  border-bottom: 1px solid var(--border);
  padding: 14px 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

header h1 {
  margin: 0;
  font-size: 20px;
  color: var(--neon);
  letter-spacing: 1px;
  text-shadow: 0 0 6px var(--neon);
}

header button {
  background: rgba(3,6,23,0.7);
  color: var(--neon);
  border: 1px solid var(--border);
  padding: 6px 12px;
  border-radius: 8px;
  cursor: pointer;
  font-weight: 700;
  transition: all 0.2s;
}

header button:hover {
  background: var(--neon);
  color: #020617;
  box-shadow: 0 0 12px var(--neon);
}

#chat-container {
  flex: 1;
  max-width: 800px;
  margin: 20px auto;
  display: flex;
  flex-direction: column;
  border-radius: 16px;
  backdrop-filter: blur(12px);
  background: rgba(2,6,23,0.6);
  border: 1px solid var(--border);
  box-shadow: 0 0 20px #38bdf830;
  overflow: hidden;
}

#messages {
  flex: 1;
  padding: 20px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.message {
  padding: 12px 18px;
  border-radius: 20px;
  max-width: 70%;
  word-wrap: break-word;
  backdrop-filter: blur(8px);
  background: rgba(3,6,23,0.4);
  border: 1px solid var(--border);
  transition: transform 0.2s;
}

.message.user {
  background: rgba(56,189,248,0.8);
  color: #020617;
  align-self: flex-end;
  box-shadow: 0 0 8px var(--neon);
}

.message.bot {
  background: rgba(255,255,255,0.05);
  color: var(--text);
  align-self: flex-start;
  border-left: 3px solid var(--neon);
}

.message:hover {
  transform: scale(1.02);
}

#input-container {
  display: flex;
  padding: 12px;
  gap: 10px;
  border-top: 1px solid var(--border);
  background: rgba(2,6,23,0.5);
}

#input-container textarea {
  flex: 1;
  resize: none;
  padding: 12px;
  border-radius: 12px;
  border: 1px solid var(--border);
  font-size: 14px;
  background: rgba(3,6,23,0.4);
  color: var(--text);
  transition: all 0.2s;
}

#input-container textarea::placeholder {
  color: var(--muted);
}

#input-container textarea:focus {
  border-color: var(--neon);
  box-shadow: 0 0 12px var(--neon50);
  outline: none;
}

#input-container button {
  background: var(--neon);
  color: #020617;
  border: none;
  padding: 10px 16px;
  border-radius: 12px;
  cursor: pointer;
  font-weight: bold;
  transition: all 0.2s;
}

#input-container button:hover {
  box-shadow: 0 0 16px var(--neon);
  transform: translateY(-2px);
}

/* particle overlay */
body::after {
  content: "";
  position: fixed;
  inset: 0;
  background-image: radial-gradient(var(--neon)33 1px, transparent 1px);
  background-size: 60px 60px;
  animation: drift 60s linear infinite;
  pointer-events: none;
}

@keyframes drift {
  from { background-position: 0 0; }
  to { background-position: 1000px 1000px; }
}