/* Shared tutor drawer: platform lessons and standalone interactive units. */
body.tutor-open { overflow: hidden; }

.tutor-sr-only {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0;
}

.tutor-drawer { position: fixed; inset: 0; z-index: 200; }
.tutor-backdrop {
  position: absolute; inset: 0; background: rgba(16, 24, 40, 0.48);
  -webkit-backdrop-filter: blur(2px); backdrop-filter: blur(2px);
}
.tutor-panel {
  position: absolute; inset: 0 0 0 auto;
  width: min(420px, 100%); height: 100dvh;
  display: flex; flex-direction: column;
  background: var(--bg-0); border-left: 1px solid var(--card-border);
  box-shadow: -18px 0 48px rgba(16, 24, 40, 0.24);
  animation: tutorIn .22s ease-out;
}
@keyframes tutorIn {
  from { transform: translateX(40px); opacity: 0; }
  to { transform: none; opacity: 1; }
}
@media (prefers-reduced-motion: reduce) {
  .tutor-panel, .tutor-typing i { animation: none; }
}

.tutor-head {
  display: flex; align-items: center; gap: 10px;
  min-height: 64px; padding: calc(12px + env(safe-area-inset-top, 0px)) 16px 12px;
  background: #fff; border-bottom: 1px solid var(--card-border);
}
.tutor-avatar { font-size: 26px; line-height: 1; }
.tutor-head-txt { display: flex; flex: 1; flex-direction: column; min-width: 0; }
.tutor-head h2 { margin: 0; font-size: 15px; font-weight: 800; color: var(--text-0); }
.tutor-topic {
  overflow: hidden; color: var(--accent-violet); font-size: 11.5px; font-weight: 700;
  text-overflow: ellipsis; white-space: nowrap;
}
.tutor-close {
  flex: 0 0 auto; width: 40px; height: 40px; margin-left: auto;
  border: 1px solid #d0d5dd; border-radius: 50%;
  background: #fff; color: var(--text-2); font-size: 15px; cursor: pointer;
}
.tutor-close:hover { color: var(--error); border-color: #fda4af; }
.tutor-close:focus-visible { outline: 3px solid #0ea5e9; outline-offset: 2px; }

.tutor-msgs {
  flex: 1; min-height: 0; overflow-y: auto; overscroll-behavior: contain;
  display: flex; flex-direction: column; gap: 10px; padding: 16px 14px;
}
.tutor-msg {
  max-width: 86%; padding: 10px 14px; border-radius: 8px;
  font-size: 13.5px; line-height: 1.6; overflow-wrap: anywhere;
  white-space: pre-wrap;
}
.tutor-msg.me {
  align-self: flex-end; background: var(--accent-gradient); color: #fff;
  border-bottom-right-radius: 3px;
}
.tutor-msg.bot {
  align-self: flex-start; background: #fff; color: var(--text-1);
  border: 1px solid var(--card-border); border-bottom-left-radius: 3px;
  box-shadow: 0 1px 3px rgba(16, 24, 40, 0.06);
}
.tutor-msg.bot.off { background: #fffbeb; border-color: #fcd34d; color: #92400e; }
.tutor-notice {
  align-self: center; max-width: 94%; padding: 7px 12px;
  color: var(--text-3); background: #f8fafc; border: 1px dashed #cbd5e1;
  border-radius: 8px; font-size: 12px; font-weight: 600; line-height: 1.45;
  text-align: center;
}
.tutor-loading { margin: auto; color: var(--text-3); font-size: 13px; text-align: center; }
.tutor-typing { display: flex; gap: 4px; align-items: center; min-height: 20px; }
.tutor-typing i {
  display: block; width: 7px; height: 7px; border-radius: 50%;
  background: var(--accent-violet); opacity: .4; animation: tutorDot 1s infinite;
}
.tutor-typing i:nth-child(2) { animation-delay: .18s; }
.tutor-typing i:nth-child(3) { animation-delay: .36s; }
@keyframes tutorDot {
  0%, 100% { opacity: .25; transform: translateY(0); }
  45% { opacity: 1; transform: translateY(-3px); }
}

.tutor-form {
  display: flex; gap: 8px; align-items: flex-end;
  padding: 12px 14px calc(12px + env(safe-area-inset-bottom, 0px));
  background: #fff; border-top: 1px solid var(--card-border);
}
.tutor-form textarea {
  flex: 1; min-width: 0; min-height: 44px; max-height: 140px; resize: vertical;
  padding: 10px 12px; border: 1px solid #d0d5dd; border-radius: 8px;
  background: #fff; color: var(--text-0); font: 14px/1.45 var(--ui);
}
.tutor-form textarea:focus {
  outline: none; border-color: var(--accent-violet);
  box-shadow: 0 0 0 3px rgba(124, 58, 237, 0.15);
}
.tutor-form textarea:disabled { background: #f2f4f7; color: var(--text-3); cursor: not-allowed; }
.tutor-form .btn { flex: 0 0 auto; min-height: 44px; border-radius: 8px; }

.lesson-tutor-btn { flex: 0 0 auto; min-height: 40px; margin-left: auto; border-radius: 8px; }
.lesson-tutor-header { flex-wrap: wrap; }
.pf-lesson-topbar {
  display: flex; align-items: center; justify-content: space-between; gap: 12px;
  margin-bottom: 18px;
}
.pf-lesson-topbar .pf-back { margin: 0; }

@media (max-width: 600px) {
  .tutor-panel { width: 100%; border-left: 0; box-shadow: none; }
  .tutor-msg { max-width: 92%; }
  .tutor-form { align-items: stretch; flex-direction: column; }
  .tutor-form textarea { flex: 0 0 auto; width: 100%; font-size: 16px; resize: none; }
  .tutor-form .btn { width: 100%; }
  .lesson-tutor-btn { flex-basis: 100%; width: 100%; margin-left: 0; }
  .pf-lesson-topbar { align-items: stretch; flex-direction: column; }
  .pf-lesson-topbar .lesson-tutor-btn { flex-basis: auto; }
}