.theorem-title {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: bold;
}

.theorem {
  padding: 1em 1em .5em 1em;
  margin: 1em 0;
  border-radius: 4px;
  border-left: 5px solid rgb(229, 254, 4); 
  background-color: rgba(229, 254, 4,.1);
}

/* Title alone in its paragraph (the exercise starts with a list): no gap before the list.
   The class is added by extras/theorem-titles.html */
.theorem > p.title-only {
  margin-bottom: 0;
}

.theorem > p.title-only .theorem-title {
  margin-bottom: 0.25rem;
}

.example {
  border-left: 5px solid #2780e3; 
  background-color: rgba(39,128,227,.1);
}

.remark {
  padding: 1em 1em .5em 1em;
  margin: 1em 0;
  border-radius: 4px;
  border-left: 5px solid rgb(1, 230, 255); 
  background-color: rgb(1, 230, 255,.1); 
}

/* Remarks are proof-like in Quarto ("*Remark 1.1* (Name). "): give them an example-style
   title (the trailing ". " is removed by extras/theorem-titles.html) */
.remark .proof-title {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: bold;
}

.remark .proof-title em {
  font-style: normal;
}

.exercise {
  border-left: 5px solid #a214c9; 
  background-color: rgba(162,20,201,.1);
}

.blank-exr {
  border-left: 5px solid #a214c9; 
  background-color: rgba(162,20,201,.1);
  padding: 1em 1em .5em 1em;
  margin: 0em 0;
  border-radius: 4px;
}

.box {
  border-left: 5px solid #a214c9; 
  background-color: rgba(162,20,201,.1);
  padding: 1em 1em .25em 1em;
  margin: 0em 0;
  margin-bottom: 1em;
  border-radius: 4px;
}

.definition {
  border-left: 5px solid rgb(238, 104, 0); 
  background-color: rgba(238, 104, 0,.1);
}

.lemma {
  border-left: 5px solid rgb(42, 235, 21); 
  background-color: rgba(42, 235, 21, .1); 
}

.proposition {
  border-left: 5px solid rgb(42, 235, 21); 
  background-color: rgba(42, 235, 21, .1); 
}

.sol {
  border-left: 5px solid #2780e3; 
  background-color: #f8f9fa;
}

/* ── Proofs ──────────────────────────────────────────────────────────────── */

.proof:not(.remark) {
  border-left: 3px solid #adb5bd;
  padding: 0.1em 0 0.1em 1em;
  margin: 1em 0 1.2em;
}

.proof:not(.remark) .proof-title {
  font-weight: 600;
}

/* QED box at the end of every proof (the PDF gets one from amsthm) */
.proof:not(.remark) > :last-child::after {
  content: "\220E";
  float: right;
  color: #6c757d;
}

.proof > p:last-child {
  margin-bottom: 0;
}

/* Collapsible proofs: ::: {.proof collapse="true"} (see extras/collapse-proofs.lua) */
details.proof-details {
  margin: 1em 0 1.2em;
}

details.proof-details > summary {
  cursor: pointer;
  font-style: italic;
  font-weight: 600;
  color: #495057;
}

details.proof-details > summary:hover {
  color: #2780e3;
}

details.proof-details > .proof {
  margin-top: 0.5em;
  border-left: none;   /* the <details> box already has a rule */
  padding-left: 0;
}

details.proof-details .proof-title {
  display: none;   /* the summary already says "Proof" */
}

.exercise-box {
  background-color: #f5e7f9;
  border-left: 5px solid #7b1fa2;
  border-radius: 4px;
  padding: 0.85em 1.25em;
  margin: 1.2em 0;
}

/* Forces the title line, bold elements, and Quarto @exr links to be black & bold
   (first-of-type: in the exercise bank the difficulty stars come before the title) */
.exercise-box > p:first-of-type,
.exercise-box > p:first-of-type strong,
.exercise-box > p:first-of-type a {
  color: #000000 !important;
  font-weight: 700 !important;
  text-decoration: none;
}

.exercise-box p:last-child {
  margin-bottom: 0;
}

/* ── Exercise hint & solution ─────────────────────────────────────────────── */

.exercise-hint {
  background-color: #e8f0fd;
  border-left: 5px solid #2780e3;
  border-radius: 4px;
  padding: 0.85em 1.25em;
  margin: 0.3em 0 0;   /* was 1em 0 0 */
}

.exercise-hint p:first-child {
  color: #000000 !important;
}

.exercise-hint p:last-child {
  margin-bottom: 0;
}

.exercise-solution {
  background-color: #e8f8f0;
  border-left: 5px solid #1a8a4a;
  border-radius: 4px;
  padding: 0.85em 1.25em;
  margin: 0.3em 0 0;   /* was 1em 0 0 */
}

.exercise-solution p:first-child {
  color: #000000 !important;
}

.exercise-solution p:last-child {
  margin-bottom: 0;
}

/* ── Question bank link inside exercise/example boxes ─────────────────────── */

.exercise, .exercise-box, .blank-exr {
  position: relative;
}

.exercise a[href*="bank.html"],
.exercise-box a[href*="bank.html"],
.blank-exr a[href*="bank.html"] {
  position: absolute;
  top: 0.55em;
  right: 0.75em;
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 2px 9px 2px 6px;
  border-radius: 999px;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  text-decoration: none;
  white-space: nowrap;
  background: rgba(123, 31, 162, 0.1);
  color: #7b1fa2;
  border: 1px solid rgba(123, 31, 162, 0.25);
  opacity: 0.7;
  transition: opacity 0.15s, background 0.15s;
}

.exercise a[href*="bank.html"]::before,
.exercise-box a[href*="bank.html"]::before,
.blank-exr a[href*="bank.html"]::before {
  content: '';
  display: inline-block;
  width: 11px;
  height: 11px;
  background-image: url('data:image/svg+xml,%3Csvg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 16 16" fill="%237b1fa2"%3E%3Cpath d="M14.5 3a.5.5 0 0 1 .5.5v9a.5.5 0 0 1-.5.5h-13a.5.5 0 0 1-.5-.5v-9a.5.5 0 0 1 .5-.5h13zm-13-1A1.5 1.5 0 0 0 0 3.5v9A1.5 1.5 0 0 0 1.5 14h13a1.5 1.5 0 0 0 1.5-1.5v-9A1.5 1.5 0 0 0 14.5 2h-13z"/%3E%3Cpath d="M3 5.5a.5.5 0 0 1 .5-.5h9a.5.5 0 0 1 0 1h-9a.5.5 0 0 1-.5-.5zM3 8a.5.5 0 0 1 .5-.5h9a.5.5 0 0 1 0 1h-9A.5.5 0 0 1 3 8zm0 2.5a.5.5 0 0 1 .5-.5h6a.5.5 0 0 1 0 1h-6a.5.5 0 0 1-.5-.5z"/%3E%3C/svg%3E');
  background-repeat: no-repeat;
  background-size: contain;
}

.exercise a[href*="bank.html"]:hover,
.exercise-box a[href*="bank.html"]:hover,
.blank-exr a[href*="bank.html"]:hover {
  opacity: 1;
  background: rgba(123, 31, 162, 0.18);
  text-decoration: none;
}

/* ── "Exercise bank" in the sidebar: a pill button with the same icon as the bank links ── */

#quarto-sidebar .sidebar-item a.sidebar-link[href$="bank.html"] {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  width: auto;
  margin: 0.2rem 0;
  padding: 3px 12px 3px 9px;
  border-radius: 999px;
  font-weight: 600;
  text-decoration: none;
  background: rgba(123, 31, 162, 0.1);
  color: #7b1fa2;
  border: 1px solid rgba(123, 31, 162, 0.25);
  transition: background 0.15s, color 0.15s;
}

/* the icon is a mask filled with the text colour, so it follows hover/active colours */
#quarto-sidebar .sidebar-item a.sidebar-link[href$="bank.html"]::before {
  content: '';
  flex-shrink: 0;
  width: 13px;
  height: 13px;
  background-color: currentColor;
  -webkit-mask: url('data:image/svg+xml,%3Csvg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 16 16"%3E%3Cpath d="M14.5 3a.5.5 0 0 1 .5.5v9a.5.5 0 0 1-.5.5h-13a.5.5 0 0 1-.5-.5v-9a.5.5 0 0 1 .5-.5h13zm-13-1A1.5 1.5 0 0 0 0 3.5v9A1.5 1.5 0 0 0 1.5 14h13a1.5 1.5 0 0 0 1.5-1.5v-9A1.5 1.5 0 0 0 14.5 2h-13z"/%3E%3Cpath d="M3 5.5a.5.5 0 0 1 .5-.5h9a.5.5 0 0 1 0 1h-9a.5.5 0 0 1-.5-.5zM3 8a.5.5 0 0 1 .5-.5h9a.5.5 0 0 1 0 1h-9A.5.5 0 0 1 3 8zm0 2.5a.5.5 0 0 1 .5-.5h6a.5.5 0 0 1 0 1h-6a.5.5 0 0 1-.5-.5z"/%3E%3C/svg%3E') no-repeat center / contain;
          mask: url('data:image/svg+xml,%3Csvg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 16 16"%3E%3Cpath d="M14.5 3a.5.5 0 0 1 .5.5v9a.5.5 0 0 1-.5.5h-13a.5.5 0 0 1-.5-.5v-9a.5.5 0 0 1 .5-.5h13zm-13-1A1.5 1.5 0 0 0 0 3.5v9A1.5 1.5 0 0 0 1.5 14h13a1.5 1.5 0 0 0 1.5-1.5v-9A1.5 1.5 0 0 0 14.5 2h-13z"/%3E%3Cpath d="M3 5.5a.5.5 0 0 1 .5-.5h9a.5.5 0 0 1 0 1h-9a.5.5 0 0 1-.5-.5zM3 8a.5.5 0 0 1 .5-.5h9a.5.5 0 0 1 0 1h-9A.5.5 0 0 1 3 8zm0 2.5a.5.5 0 0 1 .5-.5h6a.5.5 0 0 1 0 1h-6a.5.5 0 0 1-.5-.5z"/%3E%3C/svg%3E') no-repeat center / contain;
}

#quarto-sidebar .sidebar-item a.sidebar-link[href$="bank.html"]:hover {
  background: rgba(123, 31, 162, 0.18);
  color: #7b1fa2;
}

/* on the bank page itself */
#quarto-sidebar .sidebar-item a.sidebar-link.active[href$="bank.html"] {
  background: #7b1fa2;
  border-color: #7b1fa2;
  color: #fff;
}

.answer-box {
          background-color: #f8fafc;
          border: 1px solid #e2e8f0;
          border-left: 4px solid #3b82f6;
          border-radius: 8px;
          padding: 1.25rem 1.5rem;
          margin: 1.5rem 0;
          box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
        }
.answer-title {
         font-weight: 700;
          color: #1d4ed8;
          font-size: 0.875rem;
          text-transform: uppercase;
          letter-spacing: 0.05em;
          margin-bottom: 0.5rem;
        }


  details {
  border-left: 5px solid #6c757d;
  background: #f8f9fa;
  border-radius: 4px;
  padding: 0.5em 1em;
  margin: 0.75em 0;
}

details summary {
  font-weight: 600;
  cursor: pointer;
  color: #6c757d;
  user-select: none;
}

details[open] summary {
  margin-bottom: 0.5em;
}
/* space below figures produced by code cells (static plots and animations) */
.cell:has(.cell-output-display) {
  margin-bottom: 1.5em;
}

/* wide display equations (e.g. divided difference tables) scroll sideways on narrow screens */
mjx-container[display="true"] {
  overflow-x: auto;
  overflow-y: hidden;
  padding: 0.2em 0;
}