/* ===== Reset & Base ===== */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --primary: #7c3aed;
  --primary-light: #8b5cf6;
  --primary-dark: #6d28d9;
  --primary-bg: #ede9fe;
  --accent: #ec4899;
  --bg: #f5f3ff;
  --surface: #ffffff;
  --surface-2: #fafafa;
  --border: #e5e7eb;
  --text: #1f2937;
  --text-muted: #6b7280;
  --text-light: #9ca3af;
  --user-bubble: linear-gradient(135deg, #7c3aed, #ec4899);
  --ai-bubble: #f3f4f6;
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.12);
  --radius: 16px;
  --radius-sm: 8px;
  --sidebar-width: 260px;
}

html,
body {
  height: 100%;
  font-family:
    "Inter",
    -apple-system,
    BlinkMacSystemFont,
    "Segoe UI",
    sans-serif;
  background: var(--bg);
  color: var(--text);
  font-size: 15px;
  line-height: 1.5;
}

/* ===== App Layout ===== */
.app {
  display: flex;
  height: 100vh;
  height: 100dvh;
  overflow: hidden;
}

/* ===== Sidebar ===== */
.sidebar {
  width: var(--sidebar-width);
  background: linear-gradient(160deg, #6d28d9 0%, #7c3aed 50%, #a855f7 100%);
  display: flex;
  flex-direction: column;
  padding: 28px 20px;
  flex-shrink: 0;
  position: relative;
  overflow: hidden;
}

.sidebar::before {
  content: "";
  position: absolute;
  top: -60px;
  right: -60px;
  width: 200px;
  height: 200px;
  background: rgba(255, 255, 255, 0.06);
  border-radius: 50%;
}

.sidebar::after {
  content: "";
  position: absolute;
  bottom: -40px;
  left: -40px;
  width: 160px;
  height: 160px;
  background: rgba(255, 255, 255, 0.04);
  border-radius: 50%;
}

.sidebar-brand {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 32px;
  position: relative;
  z-index: 1;
}

.brand-icon {
  width: 44px;
  height: 44px;
  background: rgba(255, 255, 255, 0.2);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  backdrop-filter: blur(8px);
  flex-shrink: 0;
}

.brand-icon.small {
  width: 32px;
  height: 32px;
  border-radius: 8px;
}

.brand-name {
  font-size: 1.3rem;
  font-weight: 700;
  color: white;
  letter-spacing: -0.3px;
}

.sidebar-info {
  flex: 1;
  position: relative;
  z-index: 1;
}

.sidebar-info p {
  color: rgba(255, 255, 255, 0.75);
  font-size: 0.85rem;
  margin-bottom: 6px;
}

.sidebar-info p:first-child {
  font-weight: 600;
  color: rgba(255, 255, 255, 0.95);
  font-size: 0.9rem;
}

.sidebar-footer {
  display: flex;
  flex-direction: column;
  gap: 10px;
  position: relative;
  z-index: 1;
  padding-top: 20px;
  border-top: 1px solid rgba(255, 255, 255, 0.15);
}

.sidebar-footer a {
  color: rgba(255, 255, 255, 0.8);
  text-decoration: none;
  font-size: 0.82rem;
  display: flex;
  align-items: center;
  gap: 6px;
  transition: color 0.2s;
}

.sidebar-footer a:hover {
  color: white;
}

/* ===== Chat Area ===== */
.chat-area {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  background: var(--surface);
}

/* ===== Mobile Header ===== */
.mobile-header {
  display: none;
  align-items: center;
  gap: 10px;
  padding: 14px 16px;
  background: linear-gradient(135deg, #7c3aed, #a855f7);
  color: white;
  font-weight: 700;
  font-size: 1rem;
  flex-shrink: 0;
}

/* ===== Chat Box ===== */
.chat-box {
  flex: 1;
  overflow-y: auto;
  padding: 24px 20px;
  display: flex;
  flex-direction: column;
  gap: 16px;
  scroll-behavior: smooth;
}

.chat-box::-webkit-scrollbar {
  width: 5px;
}

.chat-box::-webkit-scrollbar-track {
  background: transparent;
}

.chat-box::-webkit-scrollbar-thumb {
  background: var(--border);
  border-radius: 10px;
}

.chat-box::-webkit-scrollbar-thumb:hover {
  background: var(--text-light);
}

/* ===== Welcome Message ===== */
.welcome-message {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 40px 20px;
  flex: 1;
  gap: 12px;
  animation: fadeInUp 0.5s ease;
}

.welcome-icon {
  font-size: 3rem;
  margin-bottom: 4px;
}

.welcome-message h2 {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--text);
}

.welcome-message p {
  color: var(--text-muted);
  font-size: 0.95rem;
  max-width: 320px;
  line-height: 1.6;
}

/* ===== Message Bubbles ===== */
.message {
  display: flex;
  flex-direction: column;
  max-width: 72%;
  animation: fadeInUp 0.3s ease;
}

.message-content {
  padding: 12px 16px;
  border-radius: 18px;
  line-height: 1.6;
  font-size: 0.93rem;
  word-wrap: break-word;
  white-space: pre-wrap;
}

.message-time {
  font-size: 0.72rem;
  color: var(--text-light);
  margin-top: 4px;
  padding: 0 4px;
}

/* User message */
.message.user {
  align-self: flex-end;
  align-items: flex-end;
}

.message.user .message-content {
  background: var(--user-bubble);
  color: white;
  border-bottom-right-radius: 4px;
  box-shadow: 0 2px 8px rgba(124, 58, 237, 0.3);
}

/* AI message */
.message.ai {
  align-self: flex-start;
  align-items: flex-start;
}

.message.ai .message-content {
  background: var(--ai-bubble);
  color: var(--text);
  border-bottom-left-radius: 4px;
  border: 1px solid var(--border);
}

/* Typing indicator */
.typing-indicator .message-content {
  display: flex;
  align-items: center;
  gap: 5px;
  padding: 14px 18px;
}

.typing-dot {
  width: 7px;
  height: 7px;
  background: var(--text-light);
  border-radius: 50%;
  animation: typingBounce 1.2s infinite;
}

.typing-dot:nth-child(2) {
  animation-delay: 0.2s;
}
.typing-dot:nth-child(3) {
  animation-delay: 0.4s;
}

/* ===== Input Area ===== */
.input-area {
  padding: 16px 20px 12px;
  background: var(--surface);
  border-top: 1px solid var(--border);
  flex-shrink: 0;
}

.input-wrapper {
  display: flex;
  align-items: center;
  gap: 10px;
  background: var(--surface-2);
  border: 1.5px solid var(--border);
  border-radius: 50px;
  padding: 6px 6px 6px 18px;
  transition:
    border-color 0.2s,
    box-shadow 0.2s;
}

.input-wrapper:focus-within {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(124, 58, 237, 0.1);
}

#user-input {
  flex: 1;
  border: none;
  background: transparent;
  font-size: 0.93rem;
  font-family: inherit;
  color: var(--text);
  outline: none;
  padding: 6px 0;
}

#user-input::placeholder {
  color: var(--text-light);
}

#chat-form button {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  border: none;
  background: var(--user-bubble);
  color: white;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition:
    transform 0.15s,
    opacity 0.15s;
  box-shadow: 0 2px 8px rgba(124, 58, 237, 0.35);
}

#chat-form button:hover {
  transform: scale(1.08);
  opacity: 0.92;
}

#chat-form button:active {
  transform: scale(0.95);
}

.input-hint {
  text-align: center;
  font-size: 0.75rem;
  color: var(--text-light);
  margin-top: 10px;
}

.input-hint a {
  color: var(--primary);
  text-decoration: none;
}

.input-hint a:hover {
  text-decoration: underline;
}

/* ===== Animations ===== */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes typingBounce {
  0%,
  60%,
  100% {
    transform: translateY(0);
  }
  30% {
    transform: translateY(-6px);
  }
}

/* ===== Responsive — Tablet ===== */
@media (max-width: 768px) {
  .sidebar {
    display: none;
  }

  .mobile-header {
    display: flex;
  }

  .chat-box {
    padding: 16px 14px;
  }

  .message {
    max-width: 85%;
  }

  .input-area {
    padding: 12px 14px 10px;
  }
}

/* ===== Responsive — Small Mobile ===== */
@media (max-width: 400px) {
  .message {
    max-width: 92%;
  }

  .welcome-message h2 {
    font-size: 1.2rem;
  }

  .welcome-icon {
    font-size: 2.5rem;
  }
}