.flat-demo-section {
  position: relative;
  overflow: hidden;
  color: var(--text-primary);
  background:
    radial-gradient(circle at 14% 8%, color-mix(in srgb, var(--primary-soft) 72%, transparent), transparent 30rem),
    radial-gradient(circle at 88% 90%, color-mix(in srgb, var(--accent) 10%, transparent), transparent 34rem),
    var(--bg-alt);
}

.flat-demo-section::before {
  position: absolute;
  inset: 0;
  pointer-events: none;
  content: "";
  opacity: .45;
  background-image: linear-gradient(color-mix(in srgb, var(--border) 45%, transparent) 1px, transparent 1px),
                    linear-gradient(90deg, color-mix(in srgb, var(--border) 45%, transparent) 1px, transparent 1px);
  background-size: 28px 28px;
}

.demo-container {
  position: relative;
  width: min(1160px, calc(100% - 36px));
  margin: 0 auto;
}

.flat-demo-section .section-title { margin-bottom: 12px; color: var(--text-primary); }
.flat-demo-section .section-subtitle { margin-bottom: 30px; color: var(--text-secondary); }
.flat-demo-section .eyebrow { text-align: center; color: var(--primary); }

.flat-demo-shell {
  overflow: hidden;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: color-mix(in srgb, var(--surface) 94%, transparent);
  box-shadow: 0 18px 48px color-mix(in srgb, var(--primary) 10%, transparent);
}

.flat-demo-taskbar {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  padding: 5px;
  border-bottom: 1px solid var(--border);
  background: color-mix(in srgb, var(--bg-alt) 82%, var(--surface));
}

.flat-demo-task {
  min-height: 42px;
  border: 0;
  border-radius: 8px;
  color: var(--text-muted);
  background: transparent;
  font: 600 .78rem/1.2 var(--font-body);
  cursor: pointer;
  transition: color .18s ease, background .18s ease;
}

.flat-demo-task:hover { color: var(--primary); }
.flat-demo-task.active { color: var(--primary); background: var(--primary-soft); }

.flat-demo-toolbar {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 24px;
  align-items: end;
  padding: 20px 22px 17px;
  border-bottom: 1px solid var(--border);
}

.flat-demo-label {
  display: block;
  margin-bottom: 8px;
  color: var(--text-muted);
  font-size: .68rem;
  font-weight: 700;
  letter-spacing: .1em;
  text-transform: uppercase;
}

.flat-demo-examples {
  display: flex;
  gap: 7px;
  overflow-x: auto;
  padding: 1px 1px 5px;
  scrollbar-width: thin;
}

.flat-demo-example {
  flex: 0 0 auto;
  min-height: 34px;
  padding: 0 13px;
  border: 1px solid var(--border-strong);
  border-radius: 999px;
  color: var(--text-secondary);
  background: var(--surface);
  font: 600 .76rem/1 var(--font-body);
  cursor: pointer;
  transition: border-color .18s ease, background .18s ease, color .18s ease;
}

.flat-demo-example:hover { border-color: var(--primary); color: var(--primary); }
.flat-demo-example.active {
  border-color: var(--primary);
  color: var(--primary);
  background: var(--primary-soft);
}

.flat-demo-loading { color: var(--text-muted); font-size: .82rem; }
.flat-demo-model {
  margin-bottom: 5px;
  padding: 7px 11px;
  border: 1px solid color-mix(in srgb, var(--accent) 32%, transparent);
  border-radius: 6px;
  color: var(--accent);
  background: color-mix(in srgb, var(--accent) 10%, transparent);
  font-size: .72rem;
  font-weight: 700;
  white-space: nowrap;
}

.flat-demo-pair {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 48px minmax(0, 1fr);
  gap: 0;
  align-items: stretch;
  padding: 22px;
}

.flat-demo-stage-loading {
  display: grid;
  min-height: 430px;
  place-items: center;
  color: var(--text-muted);
  font-size: .84rem;
}

.flat-demo-card {
  display: flex;
  flex-direction: column;
  overflow: hidden;
  min-width: 0;
  border: 1px solid var(--border);
  border-radius: 11px;
  background: var(--surface);
}

.flat-demo-card-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 43px;
  padding: 0 14px;
  border-bottom: 1px solid var(--border);
  color: var(--text-primary);
  font-size: .8rem;
  font-weight: 700;
}

.flat-demo-k-badge {
  padding: 3px 8px;
  border-radius: 999px;
  color: var(--primary);
  background: var(--primary-soft);
  font: 700 .67rem/1.4 var(--font-body);
}

.flat-demo-image-wrap {
  position: relative;
  display: grid;
  place-items: center;
  aspect-ratio: 1 / 1;
  overflow: hidden;
  background: var(--bg-alt);
}

.flat-demo-image-wrap img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: opacity .18s ease;
}

.flat-demo-image-wrap img.is-loading { opacity: .32; }
.flat-demo-placeholder {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  padding: 24px;
  color: var(--text-muted);
  font-size: .82rem;
  text-align: center;
}

.flat-demo-copy {
  min-height: 102px;
  padding: 14px 16px 16px;
  border-top: 1px solid var(--border);
}

.flat-demo-copy p { margin: 0; color: var(--text-secondary); font-size: .86rem; line-height: 1.55; }

.flat-demo-bridge {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 8px;
  color: var(--text-muted);
}

.flat-demo-bridge span { width: 1px; height: 54px; background: var(--border-strong); }
.flat-demo-bridge strong {
  writing-mode: vertical-rl;
  transform: rotate(180deg);
  color: var(--text-muted);
  font-size: .62rem;
  font-weight: 600;
  letter-spacing: .09em;
  text-transform: uppercase;
}

.flat-demo-caption-wrap {
  position: relative;
  display: flex;
  align-items: center;
  min-height: min(34vw, 430px);
  flex: 1;
  padding: 40px 38px;
  background:
    linear-gradient(145deg, var(--primary-soft), transparent 62%),
    var(--bg-alt);
}

.flat-demo-quote {
  position: absolute;
  top: 17px;
  left: 24px;
  color: color-mix(in srgb, var(--primary) 30%, transparent);
  font: 600 4.2rem/.8 var(--font-display);
}

#flat-demo-caption {
  position: relative;
  margin: 0;
  color: var(--text-primary);
  font: 500 clamp(1.12rem, 2vw, 1.55rem)/1.5 var(--font-display);
  text-wrap: balance;
}

.flat-demo-caption-meta p { color: var(--text-muted); font-size: .76rem; }

.flat-demo-sequence,
.flat-demo-arithmetic {
  padding: 22px;
}

.flat-demo-sequence-head {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 36px minmax(0, 1fr);
  align-items: center;
  gap: 10px;
  margin-bottom: 14px;
  color: var(--text-secondary);
  font: 500 .88rem/1.45 var(--font-display);
}

.flat-demo-sequence-head span:last-child { text-align: right; }
.flat-demo-sequence-arrow {
  color: var(--primary);
  font: 600 1.35rem/1 var(--font-body);
  text-align: center;
}

.flat-demo-interp-grid {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 8px;
}

.flat-demo-interp-cell,
.flat-demo-arith-cell {
  min-width: 0;
  margin: 0;
}

.flat-demo-interp-alpha {
  margin-bottom: 5px;
  color: var(--primary);
  font-size: .69rem;
  font-weight: 700;
  text-align: center;
}

.flat-demo-interp-image,
.flat-demo-arith-image {
  position: relative;
  overflow: hidden;
  aspect-ratio: 1 / 1;
  border: 1px solid color-mix(in srgb, var(--primary) 58%, var(--border));
  border-radius: 6px;
  background: var(--bg-alt);
}

.flat-demo-interp-image img,
.flat-demo-arith-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.flat-demo-interp-cell figcaption {
  display: -webkit-box;
  min-height: 4.8em;
  margin: 7px 2px 0;
  overflow: hidden;
  color: var(--text-secondary);
  font-size: .66rem;
  line-height: 1.35;
  text-align: center;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 4;
}

.flat-demo-sequence-note {
  margin-top: 10px;
  color: var(--text-muted);
  font-size: .7rem;
  text-align: right;
}

.flat-demo-arithmetic-meta {
  display: flex;
  align-items: center;
  gap: 9px;
  margin-bottom: 13px;
  color: var(--text-muted);
  font-size: .72rem;
}

.flat-demo-operation-badge {
  padding: 4px 9px;
  border-radius: 999px;
  color: var(--primary);
  background: var(--primary-soft);
  font-weight: 700;
  text-transform: capitalize;
}

.flat-demo-equation {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 30px minmax(0, 1fr) 30px minmax(0, 1fr) 34px minmax(0, 1.08fr);
  align-items: start;
  gap: 6px;
}

.flat-demo-arith-operator {
  align-self: center;
  color: var(--text-muted);
  font: 500 1.75rem/1 var(--font-body);
  text-align: center;
}

.flat-demo-arith-equals { color: var(--primary); }

.flat-demo-arith-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 6px;
  min-height: 29px;
  color: var(--text-muted);
  font-size: .6rem;
  font-weight: 700;
  letter-spacing: .025em;
  text-transform: uppercase;
}

.flat-demo-arith-head span:last-child {
  padding: 2px 6px;
  border-radius: 999px;
  color: var(--primary);
  background: var(--primary-soft);
  white-space: nowrap;
}

.flat-demo-arith-cell figcaption {
  min-height: 3.25em;
  margin: 7px 2px 0;
  color: var(--text-secondary);
  font-size: .66rem;
  line-height: 1.35;
  text-align: center;
}

.flat-demo-arith-cell figcaption strong {
  display: block;
  margin-bottom: 3px;
  color: var(--primary);
  font-size: .58rem;
  letter-spacing: .055em;
  text-transform: uppercase;
}

.flat-demo-arith-result .flat-demo-arith-image {
  border-width: 2px;
  border-color: var(--primary);
  box-shadow: 0 7px 20px color-mix(in srgb, var(--primary) 12%, transparent);
}

.flat-demo-arith-result figcaption strong { letter-spacing: .04em; }

.flat-demo-pointbar {
  display: flex;
  justify-content: center;
  gap: 6px;
  padding: 16px 18px 0;
}

.flat-demo-point {
  min-width: 52px;
  height: 29px;
  border: 1px solid var(--border-strong);
  border-radius: 999px;
  color: var(--text-muted);
  background: var(--surface);
  font: 600 .69rem/1 var(--font-body);
  cursor: pointer;
}

.flat-demo-point:hover { color: var(--primary); border-color: var(--primary); }
.flat-demo-point.active { color: var(--primary); border-color: var(--primary); background: var(--primary-soft); }

.flat-demo-expression {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 6px;
  padding: 16px 18px 0;
}

.flat-demo-term {
  padding: 4px 8px;
  border-radius: 5px;
  color: var(--text-secondary);
  background: var(--bg-alt);
  font-size: .7rem;
}

.flat-demo-term.negative { color: #a55360; background: #f8e8ea; }
body.dark-mode .flat-demo-term.negative { color: #edaeb7; background: rgba(180,78,91,.16); }

.flat-demo-controls {
  padding: 18px 22px 21px;
  border-bottom: 1px solid var(--border);
  background: color-mix(in srgb, var(--bg-alt) 72%, var(--surface));
}

.flat-demo-slider-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 18px;
  margin-bottom: 12px;
}

.flat-demo-slider-head .flat-demo-label { margin: 0; }
#flat-demo-k-output { color: var(--primary); font-size: .74rem; font-weight: 600; }

.flat-demo-slider {
  display: block;
  width: 100%;
  height: 5px;
  margin: 7px 0;
  border-radius: 999px;
  appearance: none;
  background: linear-gradient(90deg, var(--primary) 0%, var(--primary) var(--flat-demo-progress, 0%), var(--border-strong) var(--flat-demo-progress, 0%));
  cursor: pointer;
}

.flat-demo-slider::-webkit-slider-thumb {
  width: 19px;
  height: 19px;
  border: 3px solid var(--surface);
  border-radius: 50%;
  appearance: none;
  background: var(--primary);
  box-shadow: 0 0 0 1px color-mix(in srgb, var(--primary) 42%, transparent), 0 3px 9px rgba(34,37,72,.2);
}

.flat-demo-slider::-moz-range-thumb {
  width: 15px;
  height: 15px;
  border: 3px solid var(--surface);
  border-radius: 50%;
  background: var(--primary);
}

.flat-demo-ticks {
  position: relative;
  height: 18px;
  margin: 2px 9px 0;
  color: var(--text-muted);
  font-size: .68rem;
}

.flat-demo-ticks span {
  position: absolute;
  top: 0;
  min-width: 1.4rem;
  text-align: center;
  transform: translateX(-50%);
}
.flat-demo-ticks .active { color: var(--primary); font-weight: 700; }

.flat-demo-status {
  margin: 0;
  padding: 0 22px 17px;
  color: var(--text-muted);
  font-size: .72rem;
  text-align: right;
}

.flat-demo-status.error { color: #b45b68; }

@media (max-width: 760px) {
  .flat-demo-taskbar { grid-template-columns: 1fr 1fr; }
  .flat-demo-toolbar { grid-template-columns: 1fr; gap: 10px; }
  .flat-demo-model { justify-self: start; }
  .flat-demo-pair { grid-template-columns: 1fr; gap: 13px; padding: 14px; }
  .flat-demo-bridge { flex-direction: row; min-height: 28px; }
  .flat-demo-bridge span { width: 54px; height: 1px; }
  .flat-demo-bridge strong { writing-mode: horizontal-tb; transform: none; }
  .flat-demo-caption-wrap { min-height: 220px; padding: 36px 27px; }
  .flat-demo-slider-head { align-items: flex-start; flex-direction: column; gap: 5px; }
  .flat-demo-sequence, .flat-demo-arithmetic { padding: 15px 14px 18px; }
  .flat-demo-interp-grid {
    grid-template-columns: repeat(5, 72vw);
    overflow-x: auto;
    scroll-snap-type: x mandatory;
  }
  .flat-demo-interp-cell { scroll-snap-align: center; }
  .flat-demo-equation {
    grid-template-columns: repeat(7, auto);
    overflow-x: auto;
    padding-bottom: 8px;
  }
  .flat-demo-arith-cell { width: 58vw; }
  .flat-demo-arith-operator { width: 24px; }
}

@media (prefers-reduced-motion: reduce) {
  .flat-demo-image-wrap img { transition: none; }
}