:root {
  --primary: #7e6fff;
  --primary-dark: #6a5af9;
  --secondary: #00d4ff;
  --sidebar-bg: #0c1120;
  --body-bg: #121826;
  --card-bg: #1e293b;
  --input-area-bg: #121826;
  --border-color: #2d3749;
  --text-primary: #e2e8f0;
  --text-secondary: #94a3b8;
  --code-bg: #0f172a;
  --sidebar-width: 260px;
  --overlap-amount: 50px;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Inter', sans-serif;
}

body {
  background: radial-gradient(ellipse at top left, #1e293b, #121826);
  color: var(--text-primary);
  overflow: hidden;
}

a {
  color: var(--secondary);
  text-decoration: none;
  transition: color 0.3s ease;
}
a:hover {
  color: var(--primary);
}

/* Layout */
.app-container {
  display: flex;
  height: 100vh;
}

.sidebar {
  display: flex;
  flex-direction: column;
  width: var(--sidebar-width);
  flex-shrink: 0;
  height: 100vh;
  background: linear-gradient(to bottom right, #0f172a, #0c1120);
  padding: 25px 0;
  box-shadow: 6px 0 20px rgba(0, 0, 0, 0.4);
  z-index: 10;
  border-right: 1px solid var(--border-color);
}

.main-content {
  flex-grow: 1;
  background-color: var(--card-bg);
  height: 100vh;
  display: flex;
  flex-direction: column;
  margin-left: calc(-1 * var(--overlap-amount));
  border-radius: 24px 0 0 24px;
  padding: 30px;
  padding-left: calc(var(--overlap-amount) + 30px);
}

/* Sidebar */
.logo {
  display: flex;
  align-items: center;
  gap: 15px;
  padding: 0 25px 30px;
}

.logo-icon {
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  width: 48px;
  height: 48px;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
  box-shadow: 0 4px 10px rgba(126, 111, 255, 0.3);
}

.logo-text {
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: 1px;
  color: var(--text-primary);
}
.logo-text span {
  color: var(--primary);
  font-weight: 400;
  margin: 0 2px;
}

.sidebar-menu {
  padding: 0 15px;
  flex-grow: 1;
}

.menu-item {
  display: flex;
  align-items: center;
  gap: 15px;
  padding: 14px 20px;
  border-left: 4px solid transparent;
  border-radius: 10px;
  margin-bottom: 12px;
  cursor: pointer;
  transition: background 0.25s ease, color 0.25s ease, border 0.25s ease;
  color: var(--text-secondary);
  font-weight: 500;
  position: relative;
}
.menu-item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 4px;
  height: 60%;
  background: transparent;
  border-radius: 2px;
  transition: background 0.3s ease;
}
.menu-item:hover {
  color: var(--text-primary);
  background: rgba(255, 255, 255, 0.05);
}
.menu-item:hover::before {
  background: var(--primary);
}
.menu-item.active {
  background: rgba(126, 111, 255, 0.15);
  color: var(--primary);
  border-left: 4px solid var(--primary);
  font-weight: 600;
}

.sidebar-footer,
.made-by {
  padding: 12px 25px;
  font-size: 0.8rem;
  color: var(--text-secondary);
  opacity: 0.8;
  line-height: 1.4;
}
.sidebar-footer a {
  color: var(--primary);
  font-weight: 600;
  text-decoration: underline;
  transition: color 0.3s ease;
}
.sidebar-footer a:hover {
  color: var(--secondary);
}
.made-by {
  border-top: 1px solid var(--border-color);
  padding-top: 20px;
}
.sidebar-footer {
  padding-bottom: 0;
}

/* Header */
.header {
  background: rgba(255, 255, 255, 0.03);
  border-bottom: 1px solid var(--border-color);
  padding: 20px 25px;
  border-radius: 12px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.header h1 {
  font-size: 1.6rem;
}
.header-subtitle {
  color: var(--text-secondary);
  margin-top: 10px;
  margin-bottom: 20px;
}

/* Tabs */
.tabs {
  display: flex;
  gap: 10px;
}
.tab-btn {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 10px 20px;
  border-radius: 30px;
  cursor: pointer;
  transition: all 0.3s ease;
  font-weight: 600;
}
.tab-btn:hover {
  border-color: var(--primary);
  color: var(--text-primary);
}
.tab-btn.active {
  background: linear-gradient(to right, var(--primary), var(--secondary));
  border-color: var(--primary);
  color: #fff;
}

/* Chat area */
.chat-container {
  flex-grow: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  position: relative;
  height: 100%;
}
.chat-messages {
  flex-grow: 1;
  padding: 20px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 20px;
}
.message {
  max-width: 75%;
  padding: 16px 20px;
  border-radius: 14px;
  line-height: 1.6;
  font-size: 15px;
  background-color: var(--sidebar-bg);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}
.user-message {
  align-self: flex-end;
  background: linear-gradient(to right, var(--primary), var(--secondary));
  color: #fff;
  border-bottom-right-radius: 5px;
}
.bot-message {
  align-self: flex-start;
  border-left: 4px solid var(--primary);
  border-bottom-left-radius: 5px;
}

/* Chat input */
.chat-input {
  display: flex;
  padding: 0 30px 30px calc(var(--overlap-amount) + 30px);
  align-items: center;
}
.chat-input textarea {
  flex: 1;
  padding: 16px;
  border: 1px solid var(--border-color);
  border-radius: 12px;
  background-color: var(--code-bg);
  color: var(--text-primary);
  resize: none;
  min-height: 54px;
  max-height: 150px;
  font-size: 1rem;
  line-height: 1.5;
  transition: border 0.2s ease;
}
.chat-input textarea::placeholder {
  color: var(--text-secondary);
  font-style: italic;
}
.chat-input textarea:focus {
  outline: none;
  border-color: var(--primary);
}
.chat-input button {
  width: 54px;
  height: 54px;
  margin-left: 15px;
  border: none;
  border-radius: 12px;
  background: linear-gradient(to right, var(--primary), var(--secondary));
  color: white;
  cursor: pointer;
  font-size: 1.2rem;
  transition: all 0.3s ease;
}
.chat-input button:hover {
  background: var(--primary-dark);
  transform: scale(1.05);
}

/* Scrollbar */
.chat-messages::-webkit-scrollbar {
  width: 8px;
}
.chat-messages::-webkit-scrollbar-track {
  background: transparent;
}
.chat-messages::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 4px;
}
.chat-messages::-webkit-scrollbar-thumb:hover {
  background: var(--primary);
}

/* Loading */
.loading-indicator {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  padding: 12px 24px;
  background: rgba(255, 255, 255, 0.9);
  border-radius: 24px;
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 100;
  color: #555;
  font-size: 16px;
}
.loading-indicator .fa-spinner {
  margin-right: 10px;
  font-size: 18px;
}

/* Responsive */
@media (max-width: 900px) {
  .sidebar {
    position: fixed;
    transform: translateX(-100%);
    transition: transform 0.3s ease-in-out;
  }
  .main-content {
    margin-left: 0;
    border-radius: 0;
    padding: 20px;
  }
  .chat-input-area {
    margin: 0 -20px -20px -20px;
  }
  .chat-input {
    padding: 0 20px 20px 20px;
  }
}