/* ─────────────────────────────────────────────
   MedQBank — QBank Interface Styles
   ───────────────────────────────────────────── */

/* ── LAYOUT ── */
#qbank-wrap {
  display: flex;
  height: calc(100vh - var(--nav-h));
  overflow: hidden;
}

/* ── SIDEBAR ── */
#sidebar {
  width: 272px;
  min-width: 272px;
  background: var(--surface);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  transition: transform 0.25s ease;
}
#sidebar-inner { flex: 1; overflow-y: auto; padding-bottom: 16px; }
#sidebar-inner::-webkit-scrollbar { width: 4px; }
#sidebar-inner::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }

.sb-section { padding: 14px 14px 0; }
.sb-label {
  font-size: 10px; font-weight: 700;
  letter-spacing: 0.1em; text-transform: uppercase;
  color: var(--text3); margin-bottom: 8px;
}
.sb-divider { height: 1px; background: var(--border); margin: 12px 0 0; }

/* Mode toggle */
.mode-row { display: flex; gap: 5px; padding: 10px 14px; }
.mode-btn {
  flex: 1; padding: 7px 4px; border-radius: 6px;
  font-size: 11px; font-weight: 700; text-align: center;
  border: 1.5px solid var(--border);
  background: var(--surface2); color: var(--text2);
  transition: all 0.15s;
}
.mode-btn.active { background: var(--accent); border-color: var(--accent); color: #fff; }

/* Search */
.search-wrap { position: relative; }
.search-wrap input {
  width: 100%; background: var(--surface2);
  border: 1px solid var(--border); border-radius: 6px;
  padding: 8px 10px 8px 32px;
  font-family: inherit; font-size: 13px; color: var(--text);
}
.search-wrap input:focus { outline: 2px solid var(--accent); outline-offset: -1px; }
.search-icon {
  position: absolute; left: 10px; top: 50%;
  transform: translateY(-50%); color: var(--text3);
  font-size: 14px; pointer-events: none;
}

/* Exam chips */
.exam-filters { padding: 8px 14px; display: flex; flex-wrap: wrap; gap: 5px; }
.exam-chip {
  background: var(--surface2); border: 1px solid var(--border);
  border-radius: 4px; padding: 4px 9px;
  font-size: 11px; font-weight: 600; color: var(--text2);
  transition: all 0.15s;
}
.exam-chip.active { background: var(--accent); border-color: var(--accent); color: #fff; }
.exam-chip:hover:not(.active) { background: var(--accent-light); border-color: var(--accent); color: var(--accent-dark); }

/* Year select */
.sb-select {
  width: 100%; background: var(--surface2);
  border: 1px solid var(--border); border-radius: 6px;
  padding: 8px 28px 8px 10px;
  font-family: inherit; font-size: 13px; color: var(--text);
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%239c9990' stroke-width='2'%3E%3Cpath d='m6 9 6 6 6-6'/%3E%3C/svg%3E");
  background-repeat: no-repeat; background-position: right 8px center;
}
.sb-select:focus { outline: 2px solid var(--accent); outline-offset: -1px; }

/* Subject list */
.subj-list { padding: 6px 8px; }
.subj-btn {
  display: flex; align-items: center; justify-content: space-between;
  width: 100%; padding: 8px 10px; border-radius: 6px;
  background: none; color: var(--text);
  font-size: 13px; text-align: left;
  transition: all 0.12s;
}
.subj-btn:hover { background: var(--surface2); }
.subj-btn.active { background: var(--accent-light); color: var(--accent-dark); font-weight: 600; }
.subj-name { flex: 1; }
.subj-count { font-size: 11px; color: var(--text3); font-weight: 400; flex-shrink: 0; }
.subj-btn.active .subj-count { color: var(--accent); }

/* Topic list */
.topic-list { padding: 2px 6px 6px 18px; display: none; }
.topic-list.open { display: block; }
.topic-btn {
  display: flex; align-items: center; justify-content: space-between;
  width: 100%; padding: 5px 10px; border-radius: 5px;
  background: none; color: var(--text2);
  font-size: 12px; text-align: left;
  transition: all 0.12s;
}
.topic-btn:hover { background: var(--surface2); color: var(--text); }
.topic-btn.active { background: var(--accent-light); color: var(--accent-dark); font-weight: 600; }

/* Sidebar ad */
.sb-ad { padding: 12px 14px; }

/* ── MAIN CONTENT ── */
#qbank-content { flex: 1; overflow-y: auto; display: flex; flex-direction: column; }
#qbank-content::-webkit-scrollbar { width: 6px; }
#qbank-content::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }

/* Session bar */
#session-bar {
  background: var(--surface); border-bottom: 1px solid var(--border);
  padding: 8px 20px; display: flex; align-items: center;
  gap: 20px; flex-wrap: wrap; flex-shrink: 0;
}
.sess-stat { display: flex; align-items: center; gap: 6px; font-size: 12px; color: var(--text2); }
.sess-val { font-weight: 700; font-size: 15px; }
.val-correct { color: var(--green); }
.val-wrong { color: var(--red); }
.val-total { color: var(--accent-dark); }
.sess-actions { margin-left: auto; display: flex; gap: 8px; }

/* Progress */
.progress-wrap { height: 3px; background: var(--border); flex-shrink: 0; }
.progress-bar { height: 100%; background: linear-gradient(90deg, var(--accent), #5bb0e8); transition: width 0.5s ease; }

/* Tabs */
.qb-tabs { display: flex; border-bottom: 1px solid var(--border); padding: 0 20px; flex-shrink: 0; background: var(--surface); }
.qb-tab {
  padding: 11px 16px; font-size: 13px; font-weight: 500;
  color: var(--text3); border-bottom: 2px solid transparent;
  margin-bottom: -1px; transition: all 0.15s; background: none;
}
.qb-tab:hover { color: var(--text2); }
.qb-tab.active { color: var(--accent-dark); border-bottom-color: var(--accent); }

/* Content header */
.content-hdr {
  padding: 16px 20px 12px;
  display: flex; align-items: flex-start;
  justify-content: space-between; gap: 12px; flex-wrap: wrap;
  flex-shrink: 0;
}
.content-hdr-left { flex: 1; min-width: 0; }
.content-title { font-family: 'DM Serif Display', serif; font-size: 20px; color: var(--text); }
.content-subtitle { font-size: 12px; color: var(--text3); margin-top: 2px; }
.content-hdr-actions { display: flex; gap: 6px; flex-wrap: wrap; align-items: center; }

/* Loading state */
.loading-state {
  display: flex; flex-direction: column;
  align-items: center; justify-content: center;
  padding: 80px 32px; color: var(--text3); gap: 12px;
}
.spinner {
  width: 32px; height: 32px;
  border: 3px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* Questions list */
#questions-list { padding: 0 20px 12px; flex: 1; }

/* ── QUESTION CARD ── */
.q-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  margin-bottom: 14px;
  box-shadow: var(--shadow);
  transition: box-shadow 0.2s;
}
.q-card:hover { box-shadow: var(--shadow-lg); }

.q-meta { display: flex; align-items: center; gap: 6px; margin-bottom: 12px; flex-wrap: wrap; }
.q-num { font-size: 11px; font-weight: 700; color: var(--text3); }

.q-text { font-size: 15px; color: var(--text); line-height: 1.7; margin-bottom: 14px; }
.q-images { display: flex; flex-wrap: wrap; gap: 10px; margin-bottom: 12px; }
.q-images img {
  max-width: 340px; max-height: 240px; border-radius: 6px;
  border: 1px solid var(--border); object-fit: contain; cursor: zoom-in;
}

/* Options */
.options { display: grid; gap: 7px; margin-bottom: 14px; }
.opt-btn {
  display: flex; align-items: flex-start; gap: 10px;
  padding: 10px 13px; border-radius: 7px;
  border: 1.5px solid var(--border);
  background: var(--surface2);
  text-align: left; font-size: 14px; color: var(--text);
  transition: all 0.15s; width: 100%; line-height: 1.5;
}
.opt-btn:hover:not(:disabled) { background: var(--accent-light); border-color: var(--accent); }
.opt-btn:disabled { cursor: default; }
.opt-btn.selected { border-color: var(--accent); background: var(--accent-light); color: var(--accent-dark); }
.opt-btn.correct { border-color: var(--green); background: var(--green-bg); color: var(--green); }
.opt-btn.wrong { border-color: var(--red); background: var(--red-bg); color: var(--red); }
.opt-label { font-weight: 700; flex-shrink: 0; min-width: 18px; font-size: 13px; }

/* Q actions */
.q-actions { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; }
.result-badge {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 5px 11px; border-radius: 6px;
  font-size: 13px; font-weight: 500;
}
.result-correct { background: var(--green-bg); color: var(--green); }
.result-wrong { background: var(--red-bg); color: var(--red); }
.bookmark-btn {
  padding: 6px 10px; border-radius: 6px;
  background: none; border: 1.5px solid var(--border);
  color: var(--text3); font-size: 14px;
  transition: all 0.15s; line-height: 1; margin-left: auto;
}
.bookmark-btn.saved { background: var(--yellow-bg); border-color: var(--yellow); color: var(--yellow); }

/* Share btn */
.share-btn {
  padding: 6px 10px; border-radius: 6px;
  background: none; border: 1.5px solid var(--border);
  color: var(--text3); font-size: 13px; transition: all 0.15s;
}
.share-btn:hover { background: var(--surface2); color: var(--text2); }

/* ── EXPLANATION ── */
.explanation {
  margin-top: 14px; border-top: 1px solid var(--border);
  padding-top: 14px; animation: fadeUp 0.25s ease;
}
@keyframes fadeUp { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: translateY(0); } }
.exp-label {
  font-size: 11px; font-weight: 700; color: var(--accent-dark);
  text-transform: uppercase; letter-spacing: 0.08em;
  margin-bottom: 10px; display: flex; align-items: center; gap: 6px;
}
.exp-content { font-size: 14px; color: var(--text2); line-height: 1.75; }
.exp-content p { margin-bottom: 8px; }
.exp-content ul { padding-left: 20px; list-style: disc; margin-bottom: 8px; }
.exp-content li { margin-bottom: 4px; }
.exp-content strong, .exp-content b { color: var(--text); font-weight: 600; }
.exp-content table { width: 100%; border-collapse: collapse; font-size: 13px; margin: 8px 0; }
.exp-content td, .exp-content th { border: 1px solid var(--border); padding: 6px 10px; }
.exp-content th { background: var(--surface2); font-weight: 600; }
.exp-images { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 12px; }
.exp-images img {
  max-width: 400px; max-height: 300px; border-radius: 6px;
  border: 1px solid var(--border); object-fit: contain; cursor: zoom-in;
}

/* ── IN-FEED AD (between questions) ── */
.in-feed-ad {
  margin-bottom: 14px; border-radius: var(--radius);
  background: var(--surface2); border: 1px dashed var(--border);
  min-height: 90px; display: flex; align-items: center;
  justify-content: center; color: var(--text3); font-size: 12px;
}

/* ── PAGINATION ── */
.pagination {
  display: flex; align-items: center; justify-content: center;
  gap: 6px; padding: 20px;
}
.page-btn {
  width: 34px; height: 34px; border-radius: 6px;
  background: var(--surface); border: 1px solid var(--border);
  font-size: 13px; color: var(--text2);
  display: flex; align-items: center; justify-content: center;
  transition: all 0.12s;
}
.page-btn:hover:not(:disabled) { background: var(--accent-light); border-color: var(--accent); color: var(--accent-dark); }
.page-btn.active { background: var(--accent); border-color: var(--accent); color: #fff; font-weight: 700; }
.page-btn:disabled { opacity: 0.4; cursor: default; }
.page-ellipsis { padding: 0 4px; color: var(--text3); font-size: 14px; }

/* ── EMPTY / ERROR STATES ── */
.empty-state {
  text-align: center; padding: 64px 24px; color: var(--text3);
}
.empty-state h3 { font-family: 'DM Serif Display', serif; font-size: 22px; color: var(--text2); margin-bottom: 8px; }
.empty-state p { font-size: 14px; margin-bottom: 16px; }

/* ── BROKEN IMAGE HANDLING ── */
/* Hide images that fail to load — no broken icons shown */
.q-images img[style*="display: none"],
.exp-images img[style*="display: none"] {
  display: none !important;
}
/* Prevent empty image containers taking up space */
.q-images:empty,
.exp-images:empty {
  display: none !important;
}
/* While image is loading, reserve no space */
.q-images img,
.exp-images img {
  min-height: 0;
}

#lightbox {
  display: none; position: fixed; inset: 0;
  background: rgba(0,0,0,0.88); z-index: 9000;
  align-items: center; justify-content: center; cursor: zoom-out;
}
#lightbox.open { display: flex; }
#lightbox img { max-width: 90vw; max-height: 90vh; object-fit: contain; border-radius: 8px; }
#lightbox-close {
  position: fixed; top: 16px; right: 20px;
  color: #fff; font-size: 30px; cursor: pointer;
  background: none; border: none; line-height: 1;
}

/* ── MOBILE SIDEBAR ── */
#sidebar-overlay {
  display: none; position: fixed; inset: 0;
  background: rgba(0,0,0,0.4); z-index: 49;
}
@media (max-width: 900px) {
  #sidebar {
    position: fixed; left: 0; top: var(--nav-h);
    height: calc(100vh - var(--nav-h));
    z-index: 50; transform: translateX(-100%);
  }
  #sidebar.open { transform: translateX(0); box-shadow: var(--shadow-lg); }
  #sidebar-overlay.open { display: block; }
  .sb-toggle-btn { display: flex !important; }
  #questions-list { padding: 0 14px 12px; }
  .content-hdr { padding: 12px 14px 10px; }
  #session-bar { padding: 6px 14px; gap: 12px; }
}
.sb-toggle-btn {
  display: none; padding: 7px 10px; border-radius: 6px;
  background: var(--surface2); border: 1px solid var(--border);
  color: var(--text2); font-size: 18px; align-items: center;
}