:root {
  font-family: "Inter", "Segoe UI", system-ui, -apple-system, sans-serif;
  line-height: 1.5;
  color: #0e1a2b;
  background-color: #f5f7fb;
  --byui-blue: #0b4d92;
  --byui-blue-dark: #093b72;
  --byui-green: #1a7f64;
  --surface: #ffffff;
  --surface-alt: #f9fafc;
  --border: #dbe2ef;
}

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

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  padding: clamp(1rem, 3vw, 2.5rem) clamp(0.5rem, 2vw, 2rem);
  background: radial-gradient(
      circle at top,
      rgba(11, 77, 146, 0.08),
      transparent 55%
    ),
    #f5f7fb;
}

.app-shell {
  width: min(960px, 100%);
  min-height: 90vh;
  background: var(--surface);
  border-radius: 1.5rem;
  box-shadow: 0 25px 70px rgba(13, 26, 44, 0.15);
  padding: clamp(1.5rem, 3vw, 2.6rem);
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  border: 1px solid rgba(11, 77, 146, 0.05);
}

.app-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
}

.eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.25em;
  font-size: 0.78rem;
  color: var(--byui-blue);
  margin: 0 0 0.35rem;
}

.app-header h1 {
  margin: 0;
  color: var(--byui-blue-dark);
  font-size: clamp(1.8rem, 4vw, 2.4rem);
}

.app-header p {
  margin: 0.4rem 0 0;
  color: #526176;
}

.status-pill {
  background: rgba(26, 127, 100, 0.17);
  color: var(--byui-green);
  font-weight: 600;
  padding: 0.45rem 1.2rem;
  border-radius: 999px;
  border: 1px solid rgba(26, 127, 100, 0.4);
}

.control-panel {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.control-panel label {
  font-weight: 600;
}

.control-panel select {
  padding: 0.85rem;
  border-radius: 0.9rem;
  border: 1px solid var(--border);
  background: var(--surface-alt);
  font-size: 1rem;
}

.chat-window {
  flex: 1;
  background: var(--surface-alt);
  border: 1px solid var(--border);
  border-radius: 1.25rem;
  padding: 1.25rem;
  overflow-y: auto;
  scroll-behavior: smooth;
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.message {
  max-width: 700px;
  width: fit-content;
  padding: 1rem 1.1rem;
  border-radius: 1.25rem;
  border: 1px solid transparent;
  animation: fadeIn 0.25s ease;
  font-size: 1rem;
  line-height: 1.6;
  box-shadow: 0 18px 35px rgba(16, 37, 66, 0.08);
}

.message p {
  margin: 0;
  white-space: pre-wrap;
}

.message ul,
.message ol {
  margin: 0.5rem 0;
  padding-left: 1.4rem;
}

.message a {
  color: var(--byui-blue);
  text-decoration: underline;
  word-break: break-word;
}

.message--user {
  align-self: flex-end;
  background: linear-gradient(135deg, var(--byui-blue), #1479d1);
  color: white;
  border-bottom-right-radius: 0.35rem;
}

.message--bot {
  align-self: flex-start;
  background: #f8f7ff;
  border: 1px solid #e8e5ff;
  color: #1c2333;
  border-bottom-left-radius: 0.35rem;
}

.message--typing {
  font-style: italic;
  color: #6d7385;
  background: transparent;
  border: 1px dashed var(--border);
  box-shadow: none;
}

.input-bar {
  display: flex;
  gap: 0.75rem;
}

.input-bar input {
  flex: 1;
  padding: 0.9rem 1rem;
  border-radius: 0.95rem;
  border: 1px solid var(--border);
  font-size: 1rem;
  font-family: inherit;
  background: var(--surface-alt);
}

.input-bar button {
  padding: 0 1.75rem;
  border-radius: 0.95rem;
  border: none;
  font-size: 1rem;
  font-weight: 600;
  background: var(--byui-blue);
  color: white;
  cursor: pointer;
  transition: background 0.2s ease, transform 0.2s ease;
}

.input-bar button:disabled {
  opacity: 0.65;
  cursor: not-allowed;
}

.input-bar button:not(:disabled):hover {
  background: var(--byui-blue-dark);
  transform: translateY(-1px);
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(6px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 700px) {
  body {
    padding: 1rem 0.5rem;
  }

  .app-shell {
    padding: 1.25rem;
    border-radius: 1rem;
  }

  .app-header {
    flex-direction: column;
    align-items: flex-start;
  }

  .message {
    max-width: 100%;
  }
}