:root {
  --ink: #193249;
  --muted: #5f7387;
  --stroke: rgba(25, 50, 73, 0.14);
  --panel: rgba(255, 252, 245, 0.92);
  --accent-red: #ff5b70;
  --accent-blue: #4e86ff;
  --shadow: 0 18px 40px rgba(25, 50, 73, 0.12);
  --radius-lg: 28px;
  --radius-md: 20px;
  --radius-sm: 14px;
  --row-height: 116px;
}

* {
  box-sizing: border-box;
}

[hidden] {
  display: none !important;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Avenir Next", "Trebuchet MS", "Segoe UI", sans-serif;
  color: var(--ink);
  background:
    radial-gradient(circle at top left, rgba(255, 193, 69, 0.35), transparent 30%),
    radial-gradient(circle at top right, rgba(78, 134, 255, 0.22), transparent 35%),
    linear-gradient(180deg, #fbf5e6 0%, #eef6ff 100%);
}

button,
select,
input {
  font: inherit;
}

.page-shell {
  max-width: 1600px;
  margin: 0 auto;
  padding: 24px;
}

.hero {
  display: grid;
  grid-template-columns: 1.5fr auto;
  gap: 24px;
  align-items: end;
}

.hero-side {
  display: grid;
  gap: 12px;
  justify-items: end;
}

.eyebrow {
  margin: 0 0 8px;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 0.8rem;
  color: var(--muted);
}

.hero h1 {
  margin: 0;
  font-family: "Avenir Next Condensed", "Gill Sans", "Trebuchet MS", sans-serif;
  font-weight: 700;
  font-size: clamp(2.4rem, 4vw, 4.4rem);
  line-height: 0.95;
}

.hero-text {
  max-width: 58ch;
  margin: 12px 0 0;
  font-size: 1.02rem;
  color: var(--muted);
}

.hero-badge {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
  padding: 16px 20px;
  border: 1px solid var(--stroke);
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.58);
  box-shadow: var(--shadow);
}

.mode-label {
  font-weight: 700;
  color: var(--ink);
}

.mode-switch {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  border: 1px solid var(--stroke);
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.72);
  box-shadow: var(--shadow);
  color: var(--muted);
  font-weight: 700;
}

.mode-switch input {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

.switch-track {
  position: relative;
  width: 64px;
  height: 34px;
  border-radius: 999px;
  background: #66c483;
  transition: background 160ms ease;
}

.switch-thumb {
  position: absolute;
  top: 3px;
  left: 3px;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: white;
  box-shadow: 0 2px 8px rgba(25, 50, 73, 0.26);
  transition: transform 160ms ease;
}

.mode-switch input:checked + .switch-track {
  background: #4e86ff;
}

.mode-switch input:checked + .switch-track .switch-thumb {
  transform: translateX(30px);
}

.hero-dot {
  width: 16px;
  height: 16px;
  border-radius: 50%;
  display: inline-block;
}

.hero-dot-red {
  background: var(--accent-red);
}

.hero-dot-blue {
  background: var(--accent-blue);
}

.hero-dot-mix {
  background: linear-gradient(180deg, var(--accent-red), var(--accent-blue));
}

.control-strip,
.mode-panel,
.builder-layout {
  margin-top: 16px;
}

.control-strip {
  display: grid;
  grid-template-columns: 150px 1fr auto;
  gap: 16px;
}

.control-card,
.panel {
  border: 1px solid var(--stroke);
  border-radius: var(--radius-lg);
  background: var(--panel);
  box-shadow: var(--shadow);
  backdrop-filter: blur(14px);
}

.builder-layout {
  display: grid;
  grid-template-columns: minmax(220px, 20%) minmax(0, 80%);
  gap: 16px;
  align-items: start;
}

.builder-main {
  display: grid;
  gap: 16px;
  min-width: 0;
}

.mode-button-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
  gap: 10px;
  margin-top: 16px;
}

.mode-choice-button {
  display: grid;
  gap: 4px;
  min-height: 82px;
  padding: 14px;
  border: 1px solid rgba(25, 50, 73, 0.12);
  border-radius: 18px;
  background: white;
  color: var(--ink);
  text-align: left;
  cursor: pointer;
  box-shadow: 0 10px 20px rgba(25, 50, 73, 0.08);
  transition: transform 120ms ease, filter 120ms ease, box-shadow 120ms ease;
}

.mode-choice-button:hover {
  transform: translateY(-2px);
  filter: saturate(1.04);
  box-shadow: 0 14px 24px rgba(25, 50, 73, 0.12);
}

.mode-choice-button.is-active {
  color: white;
  background: linear-gradient(135deg, #173857, #2a638e);
}

.mode-choice-button span {
  color: var(--muted);
  font-size: 0.88rem;
  line-height: 1.28;
}

.mode-choice-button.is-active span {
  color: rgba(255, 255, 255, 0.82);
}

.practice-panel-top {
  display: flex;
  justify-content: space-between;
  align-items: start;
  gap: 18px;
}

.practice-actions {
  display: flex;
  justify-content: flex-end;
  gap: 10px;
  flex-wrap: wrap;
  min-width: 310px;
}

#practice-mode-panel .mode-button-row {
  margin-top: 22px;
  gap: 16px;
}

.practice-toolbar {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-top: 18px;
  flex-wrap: wrap;
}

.practice-feedback {
  color: var(--muted);
  font-weight: 700;
}

.control-card {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 16px 18px;
}

.control-card label,
.control-card span,
.panel-heading p,
.palette-tooltip p,
.status-message,
.workspace-help,
.story-note,
.amplitude-note,
.editor-note,
.editor-description,
.measurement-note {
  color: var(--muted);
}

.control-card select,
.gate-field select,
.gate-field input {
  width: 100%;
  border: 1px solid var(--stroke);
  border-radius: 12px;
  padding: 10px 12px;
  background: white;
}

.initial-bits {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.bit-toggle {
  min-width: 74px;
  padding: 10px 12px;
  border: 0;
  border-radius: 14px;
  color: white;
  cursor: pointer;
  transition: transform 120ms ease, filter 120ms ease;
}

.bit-toggle:hover,
.action-button:hover,
.palette-block:hover,
.header-mini:hover {
  transform: translateY(-2px);
  filter: saturate(1.05);
}

.bit-toggle.bit-zero {
  background: linear-gradient(135deg, #ff8390, var(--accent-red));
}

.bit-toggle.bit-one {
  background: linear-gradient(135deg, #719cff, var(--accent-blue));
}

.control-actions {
  display: flex;
  gap: 10px;
}

.action-button,
.header-mini,
.editor-button,
.timeline-chip {
  border: 0;
  border-radius: 999px;
  cursor: pointer;
}

.action-button {
  min-height: 36px;
  padding: 7px 18px;
  background: white;
  color: var(--ink);
  box-shadow: var(--shadow);
}

.action-button-primary,
.editor-button-primary {
  color: white;
  background: linear-gradient(135deg, #173857, #2a638e);
}

.action-button-solution {
  color: white;
  background: linear-gradient(135deg, #1f8d73, #2fc29a);
}

.panel {
  padding: 20px;
}

.panel-heading h2 {
  margin: 0;
  font-family: "Avenir Next Condensed", "Gill Sans", "Trebuchet MS", sans-serif;
  font-weight: 700;
  font-size: 1.9rem;
}

.panel-heading p {
  margin: 4px 0 0;
  max-width: 52ch;
}

.palette-row {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(76px, 1fr));
  justify-content: start;
  gap: 12px;
  margin-top: 16px;
}

.palette-block {
  position: relative;
  aspect-ratio: 1;
  min-height: 86px;
  border: 0;
  border-radius: 16px;
  padding: 10px;
  text-align: left;
  color: white;
  cursor: grab;
  box-shadow: 7px 9px 0 rgba(25, 50, 73, 0.12), 0 12px 22px rgba(25, 50, 73, 0.14);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  overflow: visible;
  transition: transform 120ms ease, box-shadow 120ms ease, filter 120ms ease;
}

.palette-block:active {
  transform: translate(3px, 3px);
  box-shadow: 3px 4px 0 rgba(25, 50, 73, 0.16), 0 8px 14px rgba(25, 50, 73, 0.12);
}

.palette-block[data-category="Superposition"] {
  background: linear-gradient(160deg, #ff8c6f, #ff5b70);
}

.palette-block[data-category="Single-Qubit"] {
  background: linear-gradient(160deg, #65c7b6, #1aa98d);
}

.palette-block[data-category="Phase"] {
  background: linear-gradient(160deg, #f7be54, #f78b2d);
}

.palette-block[data-category="Rotation"] {
  background: linear-gradient(160deg, #ffb24f, #f36f45);
}

.palette-block[data-category="Entangling"],
.palette-block[data-category="Two-Qubit"] {
  background: linear-gradient(160deg, #537cff, #1f9ce1);
}

.palette-block[data-category="Three-Qubit"] {
  background: linear-gradient(160deg, #5e5ef7, #46bce0);
}

.palette-block[data-category="Measurement"] {
  background: linear-gradient(160deg, #855ef7, #5b46e0);
}

.palette-code {
  font-size: 1.12rem;
  font-weight: 700;
  letter-spacing: 0.06em;
}

.palette-name {
  font-size: 0.78rem;
  line-height: 1.08;
  overflow-wrap: anywhere;
}

.palette-category {
  display: none;
}

.palette-tooltip {
  position: absolute;
  left: 0;
  bottom: calc(100% + 8px);
  z-index: 30;
  width: 320px;
  max-width: min(320px, 80vw);
  padding: 14px;
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.98);
  color: var(--ink);
  border: 1px solid rgba(25, 50, 73, 0.12);
  box-shadow: 0 16px 28px rgba(25, 50, 73, 0.16);
  opacity: 0;
  pointer-events: none;
  transform: translateY(4px);
  transition: opacity 140ms ease, transform 140ms ease;
}

.palette-tooltip strong {
  display: block;
  margin-bottom: 8px;
}

.palette-tooltip p {
  margin: 8px 0 0;
  font-size: 0.9rem;
  line-height: 1.35;
}

.palette-tooltip p:empty {
  display: none;
}

.palette-block:hover .palette-tooltip,
.palette-block:focus-visible .palette-tooltip {
  opacity: 1;
  transform: translateY(0);
}

.palette-block.is-dragging .palette-tooltip {
  display: none;
}

.palette-drag-preview {
  width: 48px;
  height: 48px;
  border-radius: 14px;
  color: white;
  display: grid;
  place-items: center;
  font-weight: 700;
  box-shadow: 0 12px 24px rgba(25, 50, 73, 0.18);
}

.workspace-dropzone {
  margin-top: 16px;
  padding: 22px 20px 28px;
  border: 0;
  border-radius: 28px;
  background: rgba(255, 255, 255, 0.76);
  overflow-x: auto;
}

.workspace-dropzone.is-dragging {
  background: rgba(255, 255, 255, 0.9);
}

.circuit-board {
  display: grid;
  grid-template-columns: minmax(170px, 190px) repeat(var(--slot-count, 4), minmax(168px, 1fr));
  gap: 0;
  width: 100%;
  min-width: 100%;
  align-items: start;
  background: transparent;
}

.register-column,
.slot-column {
  position: relative;
  background: transparent;
  border: 0;
  min-width: 0;
}

.register-column {
  z-index: 2;
}

.header-mini,
.editor-button {
  padding: 8px 12px;
  background: rgba(25, 50, 73, 0.08);
  color: var(--ink);
}

.header-mini:disabled,
.editor-button:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.slot-body {
  position: relative;
  isolation: isolate;
}

.slot-lane {
  position: relative;
  height: var(--row-height);
  padding: 10px 0;
}

.register-lane::before,
.slot-lane::before {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: calc(50% - 2px);
  height: 3px;
  background: repeating-linear-gradient(
    90deg,
    rgba(25, 50, 73, 0.16) 0 10px,
    transparent 10px 18px
  );
}

.slot-box {
  position: relative;
  z-index: 1;
  display: block;
  width: 136px;
  height: 98px;
  margin: 0 auto;
  border-radius: 20px;
  border: 3px solid rgba(25, 25, 25, 0.32);
  background: rgba(255, 255, 255, 0.96);
  color: rgba(25, 25, 25, 0.35);
  font-weight: 700;
  font-size: 0.96rem;
  line-height: 1.08;
  cursor: pointer;
}

.slot-box.is-covered {
  opacity: 0;
  pointer-events: none;
}

.register-lane {
  display: flex;
  align-items: center;
  justify-content: center;
  padding-right: 18px;
}

.register-pill {
  position: relative;
  z-index: 2;
  width: 136px;
  padding: 16px 12px;
  border-radius: 20px;
  color: #111;
  text-align: center;
  font-size: 1.05rem;
  font-weight: 700;
  background: white;
  border: 3px solid #111;
  box-shadow: none;
}

.gate-editor,
.compact-gate,
.multi-gate {
  position: absolute;
}

.gate-editor {
  z-index: 12;
  left: 50%;
  width: 156px;
  min-height: 98px;
  transform: translateX(-50%);
  padding: 12px;
  border-radius: 20px;
  background: rgba(255, 255, 255, 0.98);
  border: 1px solid rgba(25, 50, 73, 0.12);
  box-shadow: 0 18px 30px rgba(25, 50, 73, 0.1);
  overflow: auto;
  max-height: 220px;
}

.compact-gate,
.multi-gate {
  z-index: 4;
}

.editor-title {
  margin: 0;
  font-size: 0.94rem;
}

.editor-description,
.editor-note,
.measurement-note {
  margin: 6px 0 0;
  font-size: 0.76rem;
  line-height: 1.3;
}

.editor-form {
  display: grid;
  gap: 8px;
  margin-top: 10px;
}

.gate-field {
  display: grid;
  gap: 4px;
}

.gate-field label {
  font-size: 0.75rem;
  color: var(--muted);
}

.editor-footer {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 10px;
}

.editor-warning {
  color: #c54e2d;
  font-weight: 600;
  font-size: 0.72rem;
}

.compact-gate {
  left: 50%;
  width: 64px;
  height: 64px;
  transform: translateX(-50%);
  border: 0;
  border-radius: 14px;
  color: white;
  display: grid;
  place-items: center;
  font-weight: 700;
  letter-spacing: 0.04em;
  box-shadow: 7px 9px 0 rgba(25, 50, 73, 0.12), 0 12px 22px rgba(25, 50, 73, 0.14);
}

.multi-gate {
  left: 50%;
  width: 72px;
  transform: translateX(-50%);
  cursor: pointer;
}

.compact-gate.is-story-active,
.multi-gate.is-story-active {
  box-shadow: 0 0 0 5px rgba(255, 196, 76, 0.42), 0 18px 30px rgba(25, 50, 73, 0.22);
  filter: saturate(1.08);
}

.multi-connector {
  position: absolute;
  left: calc(50% - 3px);
  width: 6px;
  border-radius: 999px;
  background: rgba(25, 50, 73, 0.28);
}

.multi-node {
  position: absolute;
  left: 50%;
  width: 62px;
  height: 62px;
  transform: translateX(-50%);
  border-radius: 14px;
  color: white;
  display: grid;
  place-items: center;
  font-weight: 700;
  box-shadow: 7px 9px 0 rgba(25, 50, 73, 0.12), 0 12px 22px rgba(25, 50, 73, 0.14);
}

.multi-node.control-node {
  width: 24px;
  height: 24px;
  border-radius: 999px;
  background: #173857;
}

.category-superposition {
  background: linear-gradient(160deg, #ff8c6f, #ff5b70);
}

.category-single-qubit {
  background: linear-gradient(160deg, #65c7b6, #1aa98d);
}

.category-phase {
  background: linear-gradient(160deg, #f7be54, #f78b2d);
}

.category-rotation {
  background: linear-gradient(160deg, #ffb24f, #f36f45);
}

.category-entangling,
.category-two-qubit {
  background: linear-gradient(160deg, #537cff, #1f9ce1);
}

.category-three-qubit {
  background: linear-gradient(160deg, #5e5ef7, #46bce0);
}

.category-measurement {
  background: linear-gradient(160deg, #855ef7, #5b46e0);
}

.workspace-help {
  margin-top: 12px;
  font-size: 0.94rem;
}

.slot-column::before {
  content: "";
  position: absolute;
  left: 0;
  top: 4px;
  bottom: 4px;
  width: 3px;
  background: repeating-linear-gradient(
    180deg,
    rgba(25, 25, 25, 0.45) 0 10px,
    transparent 10px 18px
  );
}

.story-toolbar,
.timeline {
  margin-top: 14px;
}

.story-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
}

.status-message {
  margin: 0;
}

.timeline {
  display: flex;
  gap: 10px;
  overflow-x: auto;
}

.timeline-chip {
  flex: 0 0 auto;
  min-width: 104px;
  padding: 12px 14px;
  background: rgba(25, 50, 73, 0.08);
  color: var(--ink);
  text-align: left;
}

.timeline-chip.is-active {
  color: white;
  background: linear-gradient(135deg, #173857, #2a638e);
  box-shadow: 0 10px 24px rgba(25, 50, 73, 0.18);
}

.timeline-card {
  display: grid;
  gap: 2px;
}

.story-layout {
  display: grid;
  grid-template-columns: 420px 1fr;
  gap: 16px;
  margin-top: 16px;
  align-items: start;
}

.story-column {
  display: grid;
  gap: 14px;
}

.story-card,
.global-card,
.sphere-card {
  border: 1px solid var(--stroke);
  border-radius: 22px;
  padding: 16px;
  background: rgba(255, 255, 255, 0.8);
}

.story-header,
.sphere-card-header {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: start;
}

.story-card h3,
.global-card h3,
.sphere-title {
  margin: 0;
}

.story-note,
.amplitude-note {
  margin: 6px 0 0;
}

.story-summary-grid {
  display: grid;
  gap: 10px;
  margin-top: 12px;
}

.story-box {
  padding: 12px;
  border-radius: 16px;
  background: rgba(239, 247, 255, 0.8);
}

.story-box h4 {
  margin: 0 0 8px;
}

.story-box .stat-pill + .stat-pill {
  margin-top: 8px;
}

.amplitude-list {
  display: grid;
  gap: 8px;
  margin-top: 12px;
}

.amplitude-item {
  display: grid;
  gap: 4px;
}

.amplitude-head {
  display: flex;
  justify-content: space-between;
  gap: 10px;
  font-size: 0.88rem;
}

.amplitude-bar {
  overflow: hidden;
  height: 10px;
  border-radius: 999px;
  background: rgba(25, 50, 73, 0.08);
}

.amplitude-fill {
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--accent-red), #cc5ea0, var(--accent-blue));
}

.sphere-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 12px;
}

.sphere-summary {
  font-size: 0.86rem;
  color: var(--muted);
}

.sphere-canvas {
  display: block;
  width: 100%;
  max-width: 220px;
  margin: 10px auto 0;
}

.sphere-stats {
  display: grid;
  gap: 8px;
  margin-top: 14px;
}

.stat-pill {
  display: flex;
  justify-content: space-between;
  gap: 10px;
  padding: 8px 10px;
  border-radius: 999px;
  background: rgba(25, 50, 73, 0.07);
  font-size: 0.9rem;
}

@media (max-width: 1100px) {
  .control-strip,
  .story-layout,
  .builder-layout {
    grid-template-columns: 1fr;
  }

  .control-actions {
    justify-content: flex-start;
  }

  .practice-panel-top {
    flex-direction: column;
  }

  .practice-actions {
    justify-content: flex-start;
    min-width: 0;
  }
}

@media (max-width: 760px) {
  .page-shell {
    padding: 16px;
  }

  .hero {
    grid-template-columns: 1fr;
  }

  .hero-side {
    justify-items: start;
  }

  .panel,
  .control-card {
    padding: 16px;
  }

  .palette-row {
    grid-template-columns: repeat(auto-fit, minmax(90px, 1fr));
  }
}