:root {
  --bg: #f7f9ff;
  --panel: #ffffff;
  --panel-2: #edf0ff;
  --text: #1f2550;
  --muted: #5f6b91;
  --primary: #416dff;
  --accent: #ff80b5;
  --good: #22b77a;
  --warn: #ffb259;
  --bad: #ff5067;
  --chip-1: #6ec3ff;
  --chip-2: #ffd66e;
  --chip-3: #ff9fe6;
  --chip-4: #90f2ae;
  --shadow: 0 16px 40px rgba(64, 86, 178, 0.16);
}

* {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
}

body {
  margin: 0;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  font-family: "Poppins", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--text);
  background:
    radial-gradient(900px 600px at 12% -10%, rgba(110, 195, 255, 0.45) 0%, rgba(110, 195, 255, 0) 70%),
    radial-gradient(1200px 760px at 110% 0%, rgba(255, 159, 230, 0.35) 0%, rgba(255, 159, 230, 0) 75%),
    var(--bg);
}

a {
  color: var(--primary);
}

.app-header {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 24px 28px 12px;
}

.logo {
  width: 60px;
  height: 60px;
}

.titles h1 {
  margin: 0;
  font-size: 30px;
  letter-spacing: 0.5px;
}

.subtitle {
  margin: 2px 0 0;
  color: var(--muted);
}

.mode-switch {
  display: flex;
  gap: 10px;
  padding: 0 24px 18px;
  flex-wrap: wrap;
}

.mode {
  border: 0;
  padding: 10px 20px;
  border-radius: 999px;
  color: #123184;
  font-weight: 700;
  cursor: pointer;
  background: linear-gradient(135deg, #fdfdff, #dee7ff);
  box-shadow: var(--shadow);
  transition: 0.2s transform, 0.2s box-shadow;
}

.mode:hover {
  transform: translateY(-2px);
  box-shadow: 0 18px 30px rgba(65, 109, 255, 0.25);
}

.mode.active {
  outline: 3px solid rgba(65, 109, 255, 0.4);
}

.app {
  flex: 1;
  padding: 0 24px 56px;
  max-width: 1200px;
  width: 100%;
  margin: 0 auto;
}

.panel {
  display: none;
}

.panel.visible {
  display: block;
}

.card {
  background: linear-gradient(180deg, var(--panel), var(--panel-2));
  border: 1px solid rgba(65, 109, 255, 0.12);
  border-radius: 20px;
  padding: 24px;
  box-shadow: var(--shadow);
  margin: 16px 0;
}

.inputs .row {
  display: flex;
  gap: 14px;
  align-items: center;
  flex-wrap: wrap;
}

.inputs .row.space-between {
  justify-content: space-between;
}

.inputs .row.sticky {
  background: rgba(65, 109, 255, 0.08);
  padding: 12px 14px;
  border-radius: 14px;
}

.number-list {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  align-items: stretch;
}

.number-slot {
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
  width: clamp(54px, 12vw, 76px);
  aspect-ratio: 1;
  border-radius: 16px;
  border: 2px solid rgba(65, 109, 255, 0.16);
  background: rgba(255, 255, 255, 0.95);
  box-shadow: var(--shadow);
}

.number-slot:focus-within {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(65, 109, 255, 0.18);
}

.number-input {
  width: 100%;
  height: 100%;
  border: 0;
  background: transparent;
  color: var(--text);
  font-size: clamp(1.15rem, 3vw, 1.6rem);
  font-weight: 700;
  text-align: center;
  outline: none;
}

.number-input::placeholder {
  color: rgba(31, 37, 80, 0.28);
}

.number-input::-webkit-outer-spin-button,
.number-input::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

.number-input[type="number"] {
  -moz-appearance: textfield;
}

button,
select,
input {
  background: #ffffff;
  border: 1px solid rgba(65, 109, 255, 0.22);
  color: var(--text);
  padding: 10px 12px;
  border-radius: 14px;
  outline: none;
  transition: 0.2s transform, 0.2s box-shadow, 0.2s border;
}

button:hover {
  transform: translateY(-1px);
  box-shadow: 0 12px 22px rgba(65, 109, 255, 0.18);
}

button:active {
  transform: translateY(0);
}

.primary {
  background: linear-gradient(135deg, var(--primary), #7aa4ff);
  border: 0;
  color: #ffffff;
  font-weight: 800;
}

.accent {
  background: linear-gradient(135deg, var(--accent), #ff9fd0);
  border: 0;
  color: #fff8fb;
  font-weight: 800;
}

.ghost {
  background: transparent;
  border-color: rgba(65, 109, 255, 0.16);
  color: var(--muted);
}

.pill {
  background: rgba(65, 109, 255, 0.15);
  padding: 6px 12px;
  border-radius: 999px;
}

.badge {
  background: linear-gradient(135deg, #ffeaa0, #ffd0f4);
  color: #4a2d4a;
  font-weight: 800;
  padding: 6px 12px;
  border-radius: 12px;
}

.factor-area .workspace-top {
  display: flex;
  gap: 20px;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
}

.goal-toggle {
  display: flex;
  gap: 10px;
}

.toggle.goal {
  background: linear-gradient(135deg, #74e8c3, #3ccf9b);
  color: #044836;
  border: 0;
  font-weight: 800;
}

.toggle.goal.selected {
  outline: 3px solid rgba(34, 183, 122, 0.45);
}

.workspace-body {
  margin-top: 16px;
  display: grid;
  gap: 26px;
  grid-template-columns: minmax(230px, 270px) 1fr;
  align-items: start;
}

@media (max-width: 1024px) {
  .workspace-body {
    grid-template-columns: 1fr;
  }
}

.palette-wrap {
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding: 18px;
  border-radius: 18px;
  border: 1px solid rgba(65, 109, 255, 0.15);
  background: rgba(255, 255, 255, 0.92);
  box-shadow: var(--shadow);
}

.palette-wrap h3 {
  margin: 0;
}

.palette-hint {
  margin: 0;
  font-size: 0.85rem;
  color: var(--muted);
}

.prime-palette {
  display: grid;
  grid-template-columns: repeat(4, minmax(48px, 1fr));
  gap: 10px;
  align-items: stretch;
}

.prime-chip {
  cursor: grab;
  user-select: none;
  border: 0;
  color: #0c1330;
  font-weight: 800;
  width: 100%;
  min-height: 42px;
  padding: 8px 0;
  border-radius: 16px;
  box-shadow: var(--shadow);
  font-size: 1rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  letter-spacing: 0.4px;
}

.prime-chip:active {
  cursor: grabbing;
}

@media (max-width: 900px) {
  .prime-palette {
    grid-template-columns: repeat(3, minmax(48px, 1fr));
  }
}

@media (max-width: 600px) {
  .prime-palette {
    grid-template-columns: repeat(2, minmax(48px, 1fr));
  }
}

.lanes-zone {
  display: flex;
  flex-direction: column;
  gap: 22px;
}

.lanes-wrap h3,
.factor-columns-wrap h3 {
  margin: 0 0 10px;
}

.lanes {
  display: flex;
  gap: 18px;
  align-items: stretch;
  overflow-x: auto;
  padding-bottom: 6px;
}

.lanes::-webkit-scrollbar {
  height: 6px;
}

.lanes::-webkit-scrollbar-thumb {
  background: rgba(65, 109, 255, 0.32);
  border-radius: 999px;
}

.lane {
  flex: 0 0 auto;
  min-width: 190px;
  background: rgba(255, 255, 255, 0.92);
  border: 1px solid rgba(65, 109, 255, 0.15);
  border-radius: 18px;
  box-shadow: var(--shadow);
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.lane-title {
  font-weight: 800;
  text-align: center;
  margin: 0;
  font-size: 1.15rem;
}

.lane-row {
  display: flex;
  align-items: flex-start;
  gap: 16px;
}

.lane-columns {
  display: grid;
  grid-template-columns: minmax(70px, auto) 6px minmax(52px, auto);
  gap: 14px;
  align-items: start;
}

.divider {
  width: 2px;
  align-self: stretch;
  background: rgba(65, 109, 255, 0.25);
  border-radius: 999px;
}

.lane-quotients {
  display: flex;
  flex-direction: column;
  gap: 10px;
  align-items: stretch;
}

.lane-quotient {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 42px;
  padding: 8px 12px;
  border-radius: 12px;
  background: rgba(65, 109, 255, 0.1);
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--text);
}

.lane-quotient.filled {
  background: rgba(65, 109, 255, 0.18);
}

.lane-track {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  padding: 4px 0;
}


.lane-track::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  width: 2px;
  background: rgba(65, 109, 255, 0.18);
  transform: translateX(-50%);
}

.lane-track .dropzone,
.lane-track .used-prime {
  position: relative;
  z-index: 1;
}

.dropzone {
  width: 42px;
  height: 42px;
  padding: 4px 6px;
  border: 2px dashed rgba(65, 109, 255, 0.35);
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--muted);
  background: rgba(255, 255, 255, 0.85);
  font-size: 0.72rem;
  text-align: center;
}

.dropzone.over {
  border-color: var(--primary);
  background: rgba(65, 109, 255, 0.15);
  color: var(--text);
}

.dropzone.filled {
  padding: 0;
  border: 0;
}

.used-prime {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  height: 100%;
  padding: 8px 10px;
  border-radius: 14px;
  font-weight: 800;
  color: #102143;
  font-size: 1rem;
  box-shadow: var(--shadow);
}

.factor-columns {
  display: grid;
  gap: 10px;
  align-items: center;
  justify-items: center;
}

.factor-summary {
  display: contents; /* This makes the element a non-visual wrapper */
}

.factor-summary-label {
  justify-self: end;
  font-weight: 700;
  color: var(--text);
  letter-spacing: 0.4px;
}

.factor-placeholder {
  width: 4rem;
  height: 2.2rem;
}

.summary-chip {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 4rem;
  height: 2.2rem;
  padding: 6px 10px;
  border-radius: 999px;
  font-weight: 700;
  color: #102143;
  cursor: grab;
  box-shadow: var(--shadow);
  background: rgba(255, 255, 255, 0.85);
  border: 0;
}

.summary-chip:active {
  cursor: grabbing;
}

.grids {
  margin-top: 16px;
}

.factor-chip {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 4px;
  padding: 7px 12px;
  border-radius: 999px;
  font-weight: 700;
  color: #102143;
  box-shadow: var(--shadow);
  cursor: grab;
  border: 0;
}

.factor-chip:active {
  cursor: grabbing;
}

.builder-grid {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.builder-hint {
  margin: 0;
  color: var(--muted);
  font-size: 0.85rem;
}

.builder-panels {
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.result-drop {
  background: rgba(255, 255, 255, 0.94);
  padding: 16px 18px;
  border-radius: 16px;
  border: 1px solid rgba(65, 109, 255, 0.16);
  display: flex;
  flex-direction: column;
  gap: 12px;
  box-shadow: var(--shadow);
}

.result-drop[hidden] {
  display: none;
}

.result-drop.focused {
  border-color: rgba(65, 109, 255, 0.65);
  box-shadow: 0 0 0 4px rgba(65, 109, 255, 0.25);
}

.provisional-result {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--text);
  padding: 8px 12px;
  border-radius: 12px;
  background: rgba(65, 109, 255, 0.08);
  min-width: 60px;
  text-align: center;
}

.feedback-icon {
  font-size: 1.5rem;
  margin-left: 8px;
}

.result-drop.ok {
  border-color: rgba(34, 183, 122, 0.75);
  background-color: rgba(34, 183, 122, 0.08);
  box-shadow: 0 0 0 4px rgba(34, 183, 122, 0.25);
}

.result-drop.error {
  border-color: rgba(255, 80, 103, 0.75);
  background-color: rgba(255, 80, 103, 0.08);
  box-shadow: 0 0 0 4px rgba(255, 80, 103, 0.25);
}

.drop-row {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.drop-label {
  font-weight: 800;
  min-width: 70px;
  letter-spacing: 0.6px;
  color: var(--text);
}

.drop-strip {
  flex: 1;
  min-height: 52px;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 12px;
  border-radius: 14px;
  border: 2px dashed rgba(65, 109, 255, 0.26);
  background: rgba(237, 240, 255, 0.75);
}

.drop-strip.over {
  border-color: var(--primary);
  background: rgba(65, 109, 255, 0.12);
}

.drop-placeholder {
  color: var(--muted);
  font-size: 0.88rem;
}

.result-chip {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 7px 14px;
  border-radius: 999px;
  background: var(--chip-2);
  color: #2b1f08;
  font-weight: 700;
  cursor: pointer;
  position: relative;
  box-shadow: var(--shadow);
}

.clear-drop {
  font-size: 0.82rem;
  color: var(--muted);
  padding: 5px 12px;
}

.rule {
  margin: 0;
  font-size: 0.82rem;
  color: var(--muted);
  line-height: 1.45;
}

.rule-mcd {
  border-left: 3px solid var(--chip-4);
  padding-left: 10px;
}

.rule-mcm {
  border-left: 3px solid var(--chip-1);
  padding-left: 10px;
}

.drop-expression {
  margin: 0;
  font-size: 0.98rem;
  font-weight: 600;
  color: var(--text);
  letter-spacing: 0.4px;
}

.bottom-actions {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  flex-wrap: wrap;
  margin-top: 14px;
}

.result {
  display: flex;
  align-items: center;
  gap: 10px;
}

output {
  min-width: 260px;
  display: inline-block;
  padding: 10px 12px;
  border-radius: 14px;
  background: rgba(65, 109, 255, 0.12);
  line-height: 1.5;
  font-weight: 600;
}

.problem-text {
  margin: 10px 0 0;
  line-height: 1.5;
}

.problem-form {
  margin-top: 18px;
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.problem-form.locked {
  opacity: 0.75;
  pointer-events: none;
}

.problem-section {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.problem-label {
  margin: 0;
  font-weight: 600;
  color: var(--text);
}

.goal-options {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.goal-option {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 14px;
  border-radius: 14px;
  border: 1px solid rgba(65, 109, 255, 0.18);
  background: rgba(255, 255, 255, 0.9);
  font-weight: 700;
  color: var(--text);
  cursor: pointer;
  transition: 0.2s border, 0.2s box-shadow;
}

.goal-option input {
  accent-color: var(--primary);
  margin: 0;
}

.goal-option.selected {
  border-color: rgba(65, 109, 255, 0.55);
  box-shadow: 0 0 0 3px rgba(65, 109, 255, 0.18);
}

.problem-feedback {
  margin: 0;
  min-height: 1.4em;
  font-size: 0.85rem;
  color: var(--muted);
}

.app-footer {
  margin-top: auto;
  padding: 16px 22px 24px;
  border-top: 1px solid rgba(65, 109, 255, 0.12);
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--muted);
  font-size: 0.7rem;
  background: rgba(255, 255, 255, 0.85);
}

.cc {
  height: 24px;
  opacity: 0.85;
}

.cc-footer {
  height: 26px;
}

.footer-text {
  display: flex;
  flex-direction: column;
  gap: 2px;
  line-height: 1.3;
}

.footer-line {
  margin: 0;
  font-size: 0.7rem;
}

.footer-license a {
  color: var(--primary);
  text-decoration: none;
  font-weight: 500;
}

.footer-license a:hover {
  text-decoration: underline;
}

#toast {
  position: fixed;
  left: 50%;
  bottom: 26px;
  transform: translateX(-50%);
  background: rgba(255, 255, 255, 0.95);
  border: 1px solid rgba(65, 109, 255, 0.3);
  color: var(--text);
  padding: 10px 16px;
  border-radius: 14px;
  box-shadow: var(--shadow);
  opacity: 0;
  pointer-events: none;
  transition: 0.25s opacity;
}

#toast.show {
  opacity: 1;
}

.wiggle {
  animation: wiggle 0.18s linear 2;
}

@keyframes wiggle {
  0% {
    transform: translateX(0);
  }
  25% {
    transform: translateX(-2px);
  }
  50% {
    transform: translateX(2px);
  }
  75% {
    transform: translateX(-2px);
  }
  100% {
    transform: translateX(0);
  }
}
.actions {
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
  margin-top: 20px;
}

sup {
  font-size: 0.65em;
  vertical-align: top;
  line-height: 1;
  font-weight: inherit;
  margin-left: 1px;
  display: inline-block;
}

.prime-chip sup,
.used-prime sup,
.summary-chip sup,
.factor-chip sup,
.result-chip sup {
  top: -0.25em;
  position: relative;
}

.multiplier {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--muted);
}