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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  height: 100vh;
  overflow: hidden;
}

.screen {
  display: none;
  height: 100vh;
}

.screen.active {
  display: block;
}

/* Login Screen */
.login-card {
  max-width: 450px;
  border: none;
  border-radius: 15px;
}

/* Chat Screen */
#chat-screen .container-fluid {
  height: 100vh;
}

#chat-screen .row {
  height: calc(100vh - 2rem);
}

/* Messages */
#messages-container {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  padding: 1.5rem;
}

.message {
  max-width: 70%;
  padding: 0.75rem 1rem;
  border-radius: 12px;
  word-wrap: break-word;
  animation: slideIn 0.3s ease;
}

@keyframes slideIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.message.received {
  align-self: flex-start;
  background: var(--bs-body-bg);
  border: 1px solid var(--bs-border-color);
  color: var(--bs-body-color);
  box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

.message.sent {
  align-self: flex-end;
  background: var(--bs-primary);
  color: white;
  box-shadow: 0 1px 3px rgba(0,0,0,0.2);
}

.message.system {
  align-self: center;
  max-width: 90%;
  text-align: center;
  font-size: 0.9rem;
  background: var(--bs-secondary-bg);
  border: 1px solid var(--bs-border-color);
  color: var(--bs-secondary-color);
  box-shadow: 0 1px 2px rgba(0,0,0,0.05);
}

.message-username {
  font-weight: 600;
  margin-bottom: 0.25rem;
  font-size: 0.85rem;
}

.message-text {
  line-height: 1.5;
}

.message-timestamp {
  font-size: 0.7rem;
  opacity: 0.7;
  margin-top: 0.25rem;
}

/* Active states */
.room-btn.active,
.user-btn.active {
  background-color: var(--bs-primary) !important;
  color: white !important;
  border-color: var(--bs-primary) !important;
}

/* User button styling */
.user-btn {
  text-align: left;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.user-status {
  width: 8px;
  height: 8px;
  background: var(--bs-success);
  border-radius: 50%;
  display: inline-block;
}

/* Smooth scrolling */
#messages-container,
.card-body {
  scroll-behavior: smooth;
}

/* Custom scrollbar - Light mode */
::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-track {
  background: var(--bs-tertiary-bg);
}

::-webkit-scrollbar-thumb {
  background: var(--bs-secondary);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--bs-secondary-color);
}