:root {
  --bg: #f4efe4;
  --bg-alt: #fbf7ef;
  --ink: #162133;
  --ink-soft: #516076;
  --line: rgba(22, 33, 51, 0.12);
  --line-strong: rgba(22, 33, 51, 0.22);
  --panel: rgba(255, 252, 247, 0.86);
  --panel-strong: rgba(255, 250, 242, 0.96);
  --accent: #f05d3d;
  --accent-deep: #c74b30;
  --teal: #1f7a8c;
  --teal-soft: rgba(31, 122, 140, 0.15);
  --gold: #f5a623;
  --gold-soft: rgba(245, 166, 35, 0.2);
  --gold-line: rgba(245, 166, 35, 0.48);
  --success: #20684f;
  --warning: #8f5f00;
  --danger: #8d2b2b;
  --shadow: 0 24px 60px rgba(20, 28, 44, 0.12);
  --radius-xl: 28px;
  --radius-lg: 20px;
  --radius-md: 14px;
  --radius-sm: 10px;
}

* {
  box-sizing: border-box;
}

html {
  min-height: 100%;
}

body {
  min-width: 320px;
  min-height: 100vh;
  margin: 0;
  font-family: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--ink);
  background:
    radial-gradient(circle at top left, rgba(240, 93, 61, 0.12), transparent 28%),
    radial-gradient(circle at top right, rgba(31, 122, 140, 0.14), transparent 26%),
    linear-gradient(180deg, #f9f4e8 0%, #f2eadb 100%);
}

button,
input,
select {
  font: inherit;
}

button,
select {
  cursor: pointer;
}

button:disabled,
input:disabled,
select:disabled {
  cursor: not-allowed;
  opacity: 0.58;
}

.page-shell {
  width: min(1680px, 100%);
  margin: 0 auto;
  padding: 32px 20px 40px;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(300px, 0.85fr);
  gap: 28px;
  align-items: end;
  margin-bottom: 24px;
}

.eyebrow,
.section-kicker {
  margin: 0 0 8px;
  color: var(--accent-deep);
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

.hero h1,
.panel-head h2,
.card-head h3 {
  margin: 0;
  font-family: "Avenir Next", Avenir, "Segoe UI", sans-serif;
}

.hero h1 {
  max-width: 17ch;
  font-size: clamp(2.4rem, 5vw, 4.9rem);
  line-height: 0.96;
  letter-spacing: -0.045em;
}

.hero-intro {
  display: grid;
  gap: 16px;
  justify-items: start;
}

.hero-intro p {
  max-width: 62ch;
  margin: 0;
  color: var(--ink-soft);
  font-size: 1.02rem;
  line-height: 1.65;
}

.workspace {
  display: grid;
  grid-template-columns: minmax(390px, 520px) minmax(0, 1fr);
  gap: 18px;
  align-items: start;
}

.panel {
  min-width: 0;
  padding: 24px;
  border: 1px solid rgba(255, 255, 255, 0.54);
  border-radius: var(--radius-xl);
  background: var(--panel);
  box-shadow: var(--shadow);
  backdrop-filter: blur(14px);
}

.model-panel {
  display: grid;
  gap: 18px;
  align-content: start;
}

.viewport-panel {
  position: sticky;
  top: 18px;
  display: grid;
  gap: 16px;
  align-content: start;
}

.panel-head,
.card-head,
.constraint-row-head {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: flex-start;
}

.panel-head h2 {
  font-size: clamp(1.45rem, 2vw, 2rem);
  letter-spacing: -0.03em;
}

.panel-head p,
.card-head p {
  margin: 6px 0 0;
  color: var(--ink-soft);
  line-height: 1.5;
}

.model-panel > .panel-head {
  display: grid;
}

.model-panel > .panel-head .button {
  justify-self: start;
}

.card {
  min-width: 0;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: var(--panel-strong);
}

.objective-card {
  border-color: var(--gold-line);
  background:
    linear-gradient(180deg, rgba(255, 249, 239, 0.7), rgba(255, 231, 190, 0.84)),
    var(--gold-soft);
}

.objective-card.is-directly-edited,
.constraint-row.is-directly-edited {
  outline: 3px solid rgba(31, 122, 140, 0.28);
  outline-offset: 2px;
  box-shadow: 0 0 0 6px rgba(31, 122, 140, 0.08);
}

.card-head h3 {
  font-size: 1.12rem;
  letter-spacing: -0.015em;
}

.card-head.compact {
  margin-bottom: 14px;
}

.button {
  display: inline-flex;
  min-height: 42px;
  align-items: center;
  justify-content: center;
  padding: 10px 15px;
  border: 1px solid transparent;
  border-radius: 999px;
  font-weight: 750;
  line-height: 1.1;
  text-align: center;
  text-decoration: none;
  transition: transform 140ms ease, background-color 140ms ease, border-color 140ms ease;
}

.button:hover:not(:disabled) {
  transform: translateY(-1px);
}

.button-primary {
  color: #fff;
  background: var(--accent);
  box-shadow: 0 10px 22px rgba(240, 93, 61, 0.22);
}

.button-primary:hover:not(:disabled) {
  background: var(--accent-deep);
}

.button-secondary {
  color: var(--teal);
  border-color: rgba(31, 122, 140, 0.22);
  background: var(--teal-soft);
}

.button-secondary:hover:not(:disabled) {
  border-color: rgba(31, 122, 140, 0.42);
  background: rgba(31, 122, 140, 0.21);
}

.button-ghost,
.icon-button {
  color: var(--ink);
  border-color: var(--line);
  background: rgba(255, 255, 255, 0.62);
}

.button-ghost:hover:not(:disabled),
.icon-button:hover:not(:disabled) {
  border-color: var(--line-strong);
  background: #fff;
}

.icon-button {
  width: 42px;
  padding-inline: 0;
  font-size: 1.25rem;
}

.return-link {
  box-shadow: 0 10px 26px rgba(31, 122, 140, 0.12);
}

.button-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 14px;
}

.objective-form {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-top: 16px;
}

.objective-form .mode-field {
  grid-column: span 2;
}

label {
  display: grid;
  gap: 6px;
  min-width: 0;
  color: var(--ink-soft);
  font-size: 0.78rem;
  font-weight: 750;
}

input,
select {
  width: 100%;
  min-width: 0;
  min-height: 42px;
  padding: 9px 10px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-sm);
  color: var(--ink);
  background: rgba(255, 255, 255, 0.9);
}

input:hover,
select:hover {
  border-color: rgba(31, 122, 140, 0.46);
}

input:focus,
select:focus {
  border-color: var(--teal);
  outline: 3px solid rgba(31, 122, 140, 0.16);
}

.constraints-head {
  align-items: center;
  margin-bottom: 14px;
}

.constraints-head .button {
  flex: 0 0 auto;
}

.constraints-body {
  display: grid;
  gap: 12px;
}

.constraints-body:empty::before {
  content: "No constraints yet. Add one or restore the example.";
  display: block;
  padding: 18px;
  border: 1px dashed var(--line-strong);
  border-radius: var(--radius-md);
  color: var(--ink-soft);
  line-height: 1.5;
  text-align: center;
}

.constraint-row {
  display: grid;
  gap: 12px;
  min-width: 0;
  padding: 14px;
  border: 1px solid var(--line);
  border-left: 4px solid var(--constraint-color, var(--teal));
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.62);
}

.constraint-row.is-disabled {
  opacity: 0.62;
}

.constraint-row-head {
  display: grid;
  grid-template-columns: auto minmax(100px, 1fr) auto;
  align-items: end;
  gap: 10px;
}

.constraint-enabled-control {
  display: flex;
  min-height: 42px;
  align-items: center;
  gap: 8px;
  padding: 8px 2px;
  color: var(--ink);
}

.constraint-enabled-control input {
  width: 18px;
  min-height: 18px;
  margin: 0;
  accent-color: var(--teal);
}

.constraint-name-control {
  min-width: 0;
}

.constraint-remove {
  min-height: 42px;
  color: var(--danger);
}

.constraint-equation-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(58px, 1fr)) minmax(76px, 0.9fr) minmax(76px, 1fr);
  gap: 8px;
}

.analysis-card {
  background:
    radial-gradient(circle at top right, rgba(31, 122, 140, 0.1), transparent 36%),
    var(--panel-strong);
}

.status-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.status-tile {
  min-width: 0;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.62);
}

.status-label {
  display: block;
  margin-bottom: 8px;
  color: var(--ink-soft);
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.status-badge {
  display: inline-flex;
  align-items: center;
  min-height: 27px;
  padding: 5px 9px;
  border-radius: 999px;
  font-size: 0.78rem;
  line-height: 1;
}

.status-badge.neutral {
  color: var(--ink-soft);
  background: rgba(81, 96, 118, 0.12);
}

.status-badge.success {
  color: var(--success);
  background: rgba(32, 104, 79, 0.14);
}

.status-badge.warning {
  color: var(--warning);
  background: rgba(245, 166, 35, 0.2);
}

.status-badge.danger {
  color: var(--danger);
  background: rgba(141, 43, 43, 0.12);
}

.status-tile p {
  margin: 9px 0 0;
  color: var(--ink-soft);
  font-size: 0.88rem;
  line-height: 1.48;
}

.viewport-head {
  align-items: center;
}

.camera-toolbar {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 8px;
}

.camera-toolbar .button {
  min-height: 38px;
  padding-block: 8px;
}

.camera-toolbar .icon-button {
  width: 38px;
  padding-inline: 0;
}

.viewport-instructions,
.viewport-status {
  margin: 0;
  color: var(--ink-soft);
  line-height: 1.52;
}

.viewport-instructions {
  font-size: 0.9rem;
}

.viewport-frame {
  position: relative;
  min-width: 0;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background:
    radial-gradient(circle at 65% 24%, rgba(31, 122, 140, 0.1), transparent 35%),
    linear-gradient(180deg, #fffef8 0%, #faf5ec 100%);
}

.viewport {
  position: relative;
  width: 100%;
  height: clamp(500px, 70vh, 800px);
  overflow: hidden;
  touch-action: none;
  cursor: grab;
}

.viewport:active {
  cursor: grabbing;
}

.viewport.is-handle-hovered {
  cursor: move;
}

.viewport.is-plane-dragging {
  cursor: grabbing;
}

.viewport canvas {
  display: block;
  width: 100% !important;
  height: 100% !important;
  outline: none;
}

.plane-drag-readout {
  position: absolute;
  top: 12px;
  left: 12px;
  z-index: 2;
  max-width: calc(100% - 24px);
  padding: 9px 12px;
  border: 1px solid rgba(31, 122, 140, 0.28);
  border-radius: 999px;
  color: var(--ink);
  background: rgba(255, 252, 247, 0.94);
  box-shadow: 0 8px 24px rgba(20, 28, 44, 0.12);
  backdrop-filter: blur(10px);
  font-size: 0.8rem;
  font-weight: 800;
  pointer-events: none;
}

.viewport-key {
  position: absolute;
  right: 12px;
  bottom: 12px;
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 8px 12px;
  max-width: calc(100% - 24px);
  padding: 8px 10px;
  border: 1px solid rgba(255, 255, 255, 0.7);
  border-radius: 999px;
  color: var(--ink-soft);
  background: rgba(255, 252, 247, 0.84);
  box-shadow: 0 8px 24px rgba(20, 28, 44, 0.09);
  backdrop-filter: blur(10px);
  font-size: 0.75rem;
  font-weight: 700;
  pointer-events: none;
}

.viewport-key span {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.key-swatch {
  width: 13px;
  height: 13px;
  border-radius: 4px;
}

.key-handle {
  display: inline-block;
  width: 12px;
  height: 12px;
  border: 2px solid #fff;
  background: var(--teal);
  box-shadow: 0 0 0 1px rgba(22, 33, 51, 0.28);
}

.constraint-handle-key {
  border-radius: 50%;
}

.objective-handle-key {
  background: var(--gold);
  transform: rotate(45deg) scale(0.82);
}

.feasible-swatch {
  border: 1px solid rgba(31, 122, 140, 0.65);
  background: rgba(31, 122, 140, 0.28);
}

.objective-swatch {
  border: 1px solid rgba(245, 166, 35, 0.9);
  background: rgba(245, 166, 35, 0.34);
}

.key-arrow {
  color: var(--accent-deep);
  font-size: 1.05rem;
  line-height: 1;
}

.viewport-status {
  min-height: 24px;
  padding: 10px 12px;
  border-radius: var(--radius-sm);
  background: rgba(31, 122, 140, 0.08);
  font-size: 0.86rem;
}

.noscript-message {
  width: min(720px, calc(100% - 40px));
  margin: 20px auto;
  padding: 16px;
  border: 1px solid rgba(141, 43, 43, 0.24);
  border-radius: var(--radius-md);
  color: var(--danger);
  background: rgba(255, 255, 255, 0.9);
}

:focus-visible {
  outline: 3px solid rgba(31, 122, 140, 0.42);
  outline-offset: 3px;
}

@media (max-width: 1180px) {
  .workspace {
    grid-template-columns: minmax(360px, 470px) minmax(0, 1fr);
  }

  .viewport-head {
    display: grid;
  }

  .camera-toolbar {
    justify-content: flex-start;
  }
}

@media (max-width: 980px) {
  .hero {
    grid-template-columns: 1fr;
    gap: 18px;
  }

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

  .viewport-panel {
    position: static;
  }

  .viewport {
    height: clamp(460px, 66vh, 700px);
  }
}

@media (max-width: 700px) {
  .page-shell {
    padding: 22px 12px 28px;
  }

  .hero h1 {
    font-size: clamp(2.25rem, 12vw, 3.5rem);
  }

  .panel {
    padding: 16px;
    border-radius: 22px;
  }

  .panel-head,
  .card-head,
  .constraints-head {
    display: grid;
  }

  .constraints-head .button,
  .model-panel > .panel-head .button {
    justify-self: stretch;
  }

  .objective-form .mode-field {
    grid-column: span 2;
  }

  .constraint-row-head {
    grid-template-columns: auto minmax(0, 1fr);
  }

  .constraint-remove {
    grid-column: 1 / -1;
    justify-self: start;
  }

  .constraint-equation-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .constraint-equation-grid label:last-child {
    grid-column: span 2;
  }

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

  .camera-toolbar {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .camera-toolbar .button,
  .camera-toolbar .icon-button {
    width: auto;
  }

  .viewport {
    height: min(62svh, 520px);
  }

  .viewport-key {
    left: 8px;
    right: 8px;
    bottom: 8px;
    justify-content: flex-start;
    max-width: none;
    border-radius: var(--radius-md);
  }
}

@media (max-width: 430px) {
  .objective-form,
  .constraint-equation-grid {
    grid-template-columns: 1fr;
  }

  .objective-form .mode-field,
  .constraint-equation-grid label:last-child {
    grid-column: auto;
  }

  .constraint-row-head {
    grid-template-columns: 1fr;
  }

  .constraint-remove {
    grid-column: auto;
    justify-self: stretch;
  }

  .camera-toolbar {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .camera-toolbar #reset-camera {
    grid-column: span 2;
  }

  .viewport-key {
    display: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}