/* ===== Discuss panel ===== */

.discuss-panel {
  display: none;
  flex-direction: column;
  position: sticky;
  top: 120px;
  align-self: start;
  max-height: calc(100vh - 140px);
  border-left: 1px solid var(--bs-border-color);
  background: #fff;
  overflow: hidden;
}

.discuss-open .discuss-panel {
  display: flex;
}

.discuss-open .lesson-main {
  align-self: start;
}

.discuss-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.5rem 1rem 0.5rem;
  border-bottom: 1px solid var(--bs-border-color);
  flex-shrink: 0;
}

.discuss-title {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--bs-body-color);
}

.discuss-close {
  font-size: 1.25rem;
  line-height: 1;
  border: none;
  background: none;
  cursor: pointer;
}

.discuss-messages {
  padding: 0.75rem;
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
  flex: 1;
  min-height: 0;
  overflow-y: auto;
}

.discuss-message {
  max-width: 90%;
  padding: 0.6rem 0.85rem;
  border-radius: 12px;
  font-size: 0.85rem;
  line-height: 1.5;
  white-space: pre-wrap;
}

.discuss-message-label {
  font-size: 0.68rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  margin-bottom: 0.15rem;
  color: var(--bs-secondary-color);
}

.discuss-message-tutor {
  align-self: flex-start;
  background: #f3f4f6;
  border-bottom-left-radius: 4px;
  position: relative;
}

.discuss-message-user {
  align-self: flex-end;
  background: var(--accent-light);
  border-bottom-right-radius: 4px;
}

.discuss-typing {
  align-self: flex-start;
  padding: 0.6rem 0.85rem;
}

.discuss-typing-dots {
  display: flex;
  gap: 4px;
  padding: 4px 0;
}

.discuss-typing-dots span {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--bs-secondary-color);
  opacity: 0.4;
  animation: discussTypingDot 1.2s infinite;
}

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

@keyframes discussTypingDot {
  0%, 60%, 100% { opacity: 0.4; transform: translateY(0); }
  30% { opacity: 1; transform: translateY(-3px); }
}

.discuss-input-area {
  padding: 0.75rem;
  display: flex;
  align-items: flex-end;
  gap: 0.5rem;
}

.discuss-textarea {
  flex: 1;
  min-width: 0;
  border: 1.5px solid var(--bs-border-color);
  border-radius: 8px;
  padding: 0.6rem 0.75rem;
  font-size: 0.85rem;
  font-family: inherit;
  resize: none;
  line-height: 1.45;
}

.discuss-textarea:focus {
  outline: none;
  border-color: var(--accent);
}

.discuss-send {
  flex-shrink: 0;
}

.discuss-send:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.discuss-opening {
  font-size: 0.85rem;
  color: var(--bs-secondary-color);
  text-align: center;
  padding: 1rem 1rem 0.25rem;
  line-height: 1.5;
}

/* Topbar button */
.discuss-toggle {
  display: flex;
  align-items: center;
}

.discuss-toggle.active {
  background: var(--accent-light);
  border-color: var(--accent);
  color: var(--accent);
}

/* ===== Mobile overlay ===== */
@media (max-width: 768px) {
  .discuss-panel {
    position: fixed;
    inset: 0;
    z-index: 1050;
    border-left: none;
    padding-top: 0;
  }

  .discuss-toggle-label { display: none; }
}

@media (max-width: 576px) {
  .discuss-message { max-width: 95%; }
}