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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: #0d1117;
  color: #c9d1d9;
  height: 100vh;
  display: flex;
  flex-direction: column;
}

.hidden {
  display: none !important;
}

/* ---------- Login ---------- */
.screen {
  display: flex;
  flex-direction: column;
  height: 100vh;
}

#login-screen {
  align-items: center;
  justify-content: center;
}

.login-card {
  text-align: center;
  background: #161b22;
  padding: 3rem;
  border-radius: 12px;
  border: 1px solid #30363d;
}

.login-card h1 {
  margin-bottom: 0.5rem;
}

.login-card p {
  margin-bottom: 1.5rem;
  color: #8b949e;
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.6rem 1.2rem;
  font-size: 1rem;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  text-decoration: none;
  color: #fff;
  background: #238636;
}

.btn:hover {
  background: #2ea043;
}

.btn-github {
  background: #24292f;
}

.btn-github:hover {
  background: #32383f;
}

.btn-small {
  padding: 0.3rem 0.8rem;
  font-size: 0.85rem;
}

/* ---------- Chat ---------- */
header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1rem;
  background: #161b22;
  border-bottom: 1px solid #30363d;
}

header h1 {
  font-size: 1.2rem;
}

.user-info {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

#user-avatar {
  width: 28px;
  height: 28px;
  border-radius: 50%;
}

main#messages {
  flex: 1;
  overflow-y: auto;
  padding: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.msg {
  max-width: 70%;
  padding: 0.75rem 1rem;
  border-radius: 12px;
  line-height: 1.4;
  white-space: pre-wrap;
  word-break: break-word;
}

.msg.user {
  align-self: flex-end;
  background: #238636;
  color: #fff;
}

.msg.assistant {
  align-self: flex-start;
  background: #21262d;
}

#chat-form {
  display: flex;
  padding: 0.75rem 1rem;
  gap: 0.5rem;
  background: #161b22;
  border-top: 1px solid #30363d;
}

#chat-input {
  flex: 1;
  padding: 0.6rem 0.8rem;
  border: 1px solid #30363d;
  border-radius: 6px;
  background: #0d1117;
  color: #c9d1d9;
  font-size: 1rem;
  outline: none;
}

#chat-input:focus {
  border-color: #58a6ff;
}

#model-select {
  padding: 0.6rem 0.5rem;
  border: 1px solid #30363d;
  border-radius: 6px;
  background: #0d1117;
  color: #c9d1d9;
  font-size: 0.85rem;
  outline: none;
  cursor: pointer;
}

#model-select:focus {
  border-color: #58a6ff;
}