*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  overflow-x: hidden;
  max-width: 100vw;
}

:root {
  --purple: #533afd;
  --purple-hover: #4434d4;
  --purple-deep: #2e2b8c;
  --purple-light: #b9b9f9;
  --purple-bg: rgba(83, 58, 253, 0.06);
  --heading: #061b31;
  --label: #273951;
  --body: #425466;
  --white: #ffffff;
  --bg: #ffffff;
  --bg-alt: #f6f9fc;
  --brand-dark: #0a2540;
  --brand-gradient: linear-gradient(135deg, #0a2540 0%, #1c1e54 50%, #2e2b8c 100%);
  --ruby: #ea2261;
  --success: #15be53;
  --success-text: #108c3d;
  --warning: #8a6912;
  --border: #e5edf5;
  --border-strong: #d4dfec;
  --border-purple: #b9b9f9;
  --shadow-card: rgba(50, 50, 93, 0.18) 0px 30px 60px -16px, rgba(0, 0, 0, 0.08) 0px 18px 36px -18px;
  --shadow-sm: rgba(50, 50, 93, 0.1) 0px 6px 12px -2px, rgba(0, 0, 0, 0.06) 0px 3px 7px -3px;
  --ease: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --content: 1280px;
  --radius-lg: 18px;
  --radius-md: 12px;
  --radius-sm: 8px;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 88px;
}

body {
  margin: 0;
  font-family:
    "Inter",
    "Noto Sans SC",
    -apple-system,
    sans-serif;
  background:
    radial-gradient(circle at top right, rgba(83, 58, 253, 0.08), transparent 28%),
    linear-gradient(180deg, #fdfefe 0%, #f6f9fc 100%);
  color: var(--body);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  font-size: 17px;
}

a {
  color: inherit;
  text-decoration: none;
}

h1,
h2,
h3,
h4,
p,
ul,
ol,
dl,
dd {
  margin: 0;
}

code {
  background: rgba(10, 37, 64, 0.06);
  border-radius: 6px;
  padding: 0.08rem 0.38rem;
  font-family: "Source Code Pro", "SFMono-Regular", monospace;
  font-size: 0.95em;
}

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 72px;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(20px) saturate(1.8);
  border-bottom: 1px solid var(--border);
  z-index: 100;
  display: flex;
  align-items: center;
  gap: 18px;
  padding: 0 36px;
}

.brand {
  font-weight: 700;
  font-size: 1.08rem;
  color: var(--heading);
  letter-spacing: -0.03em;
  display: flex;
  align-items: center;
  gap: 10px;
}

.brand::before {
  content: "";
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--purple);
  box-shadow: 0 0 0 6px rgba(83, 58, 253, 0.12);
  flex: 0 0 auto;
}

.nav {
  display: flex;
  align-items: center;
  gap: 4px;
  margin-left: 28px;
  flex-wrap: wrap;
}

.nav-link {
  color: var(--label);
  font-size: 0.9rem;
  font-weight: 400;
  padding: 8px 16px;
  border-radius: 6px;
  transition: var(--ease);
}

.nav-link:hover {
  color: var(--purple);
  background: var(--purple-bg);
}

.nav-link.active {
  color: var(--purple);
  background: rgba(83, 58, 253, 0.1);
}

.nav-divider {
  width: 1px;
  height: 18px;
  background: var(--border-strong);
  margin: 0 4px;
}

.nav-user {
  color: var(--label);
  font-size: 0.88rem;
  font-weight: 500;
  margin-left: 6px;
}

.nav form {
  margin: 0;
}

.page-shell {
  max-width: var(--content);
  margin: 0 auto;
  padding: 108px 36px 72px;
}

.page-shell-wide {
  max-width: 1440px;
}

.flash-stack {
  display: grid;
  gap: 12px;
  margin-bottom: 28px;
}

.flash {
  padding: 14px 16px;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  box-shadow: var(--shadow-sm);
}

.flash-success {
  background: #eafaf0;
  border-color: #bde8ca;
  color: var(--success-text);
}

.flash-error {
  background: #fff0ee;
  border-color: #f7c7be;
  color: #b33520;
}

.flash-warning {
  background: #fff7e5;
  border-color: #f0de9d;
  color: var(--warning);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--purple);
  margin-bottom: 14px;
}

.eyebrow::before {
  content: "";
  width: 18px;
  height: 1px;
  background: currentColor;
  opacity: 0.4;
}

h1,
.content-header h1,
.form-card h1 {
  color: var(--heading);
  font-size: clamp(2.4rem, 4vw, 4rem);
  font-weight: 300;
  letter-spacing: -1.6px;
  line-height: 1.06;
}

h2 {
  color: var(--heading);
  font-size: clamp(1.5rem, 2.2vw, 2.4rem);
  font-weight: 300;
  letter-spacing: -0.8px;
  line-height: 1.12;
}

h3 {
  color: var(--heading);
  font-size: 1.3rem;
  font-weight: 500;
  letter-spacing: -0.3px;
  line-height: 1.25;
}

.hero-text,
.field-note,
.artifact-note,
.workspace-card p,
.content-header p,
.theory-text-card p,
.info-card li,
.result-card p {
  color: var(--body);
}

.lab-hero {
  display: grid;
  grid-template-columns: minmax(0, 1.35fr) minmax(320px, 0.95fr);
  gap: 24px;
  align-items: stretch;
  margin-bottom: 28px;
}

.lab-copy,
.hero-panel,
.workspace-card,
.form-card,
.table-card,
.info-card,
.result-card,
.stats-card {
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
}

.lab-copy {
  position: relative;
  overflow: hidden;
  background: var(--brand-gradient);
  color: #fff;
  padding: 40px;
  box-shadow: var(--shadow-card);
}

.lab-copy::before {
  content: "";
  position: absolute;
  top: -40%;
  right: -16%;
  width: 420px;
  height: 420px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(83, 58, 253, 0.22), transparent 68%);
  pointer-events: none;
}

.lab-copy .eyebrow,
.lab-copy h1,
.lab-copy p,
.lab-copy a {
  position: relative;
  z-index: 1;
}

.lab-copy .eyebrow {
  color: var(--purple-light);
}

.lab-copy .eyebrow::before {
  opacity: 0.6;
}

.lab-copy h1 {
  color: #fff;
  max-width: 14ch;
  margin-bottom: 18px;
}

.lab-copy .hero-text {
  color: rgba(255, 255, 255, 0.76);
  max-width: 58ch;
  font-size: 1.08rem;
}

.hero-panel {
  background: linear-gradient(180deg, #ffffff 0%, #f8fbff 100%);
  padding: 18px;
  display: grid;
  gap: 16px;
}

.instrument-panel {
  align-content: start;
}

.metric-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 20px;
  box-shadow: var(--shadow-sm);
}

.metric-card.accent {
  background: linear-gradient(180deg, rgba(83, 58, 253, 0.1) 0%, rgba(83, 58, 253, 0.04) 100%);
  border-color: rgba(83, 58, 253, 0.18);
}

.metric-card span,
.stats-card span,
.panel-heading .eyebrow,
.result-grid dt {
  color: var(--label);
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.metric-card strong {
  display: block;
  color: var(--heading);
  margin-top: 8px;
  font-size: 1.02rem;
  font-weight: 600;
  letter-spacing: -0.02em;
}

.metric-card p {
  margin-top: 10px;
  font-size: 0.95rem;
}

.formula {
  font-style: italic;
}

.data-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.workspace-grid,
.grid-two {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px;
}

.workspace-card,
.form-card,
.table-card,
.info-card,
.result-card {
  background: #fff;
  padding: 28px;
}

.workspace-card {
  min-height: 100%;
}

.workspace-card h2,
.panel-heading h2 {
  margin-bottom: 12px;
}

.content-header {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 20px;
  margin-bottom: 28px;
}

.content-header p {
  max-width: 72ch;
  margin-top: 10px;
}

.panel-heading {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 18px;
}

.panel-heading.compact {
  margin-bottom: 14px;
}

.panel-heading .eyebrow {
  margin-bottom: 8px;
}

.primary-button,
.secondary-button,
.ghost-button,
button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 22px;
  border-radius: 6px;
  font-size: 0.95rem;
  font-weight: 500;
  transition: var(--ease);
  cursor: pointer;
  border: none;
  font-family: inherit;
}

.primary-button,
button.primary-button {
  background: var(--purple);
  color: #fff;
  box-shadow: var(--shadow-sm);
}

.primary-button:hover,
button.primary-button:hover {
  background: var(--purple-hover);
  box-shadow: var(--shadow-card);
  transform: translateY(-1px);
}

.secondary-button {
  background: rgba(83, 58, 253, 0.08);
  color: var(--purple);
  border: 1px solid rgba(83, 58, 253, 0.14);
}

.secondary-button:hover {
  background: rgba(83, 58, 253, 0.12);
  transform: translateY(-1px);
}

.ghost-button {
  background: transparent;
  color: var(--purple);
  border: 1px solid var(--border-purple);
}

.ghost-button:hover,
button:hover {
  background: var(--purple-bg);
  transform: translateY(-1px);
}

.hero-actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 28px;
}

.form-page {
  padding-top: 10px;
}

.form-card {
  width: min(100%, 820px);
  margin: 0 auto;
  box-shadow: var(--shadow-card);
}

.stack-form {
  display: grid;
  gap: 18px;
}

.stack-form label {
  display: grid;
  gap: 8px;
}

.stack-form label > span {
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--label);
}

input,
textarea,
select {
  width: 100%;
  padding: 14px 16px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: #fff;
  color: var(--heading);
  font: inherit;
  transition: var(--ease);
}

input:focus,
textarea:focus,
select:focus {
  outline: none;
  border-color: var(--purple);
  box-shadow: 0 0 0 4px rgba(83, 58, 253, 0.12);
}

textarea {
  resize: vertical;
}

.inline-fields {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.inline-fields-3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.inline-fields-4 {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.form-section,
.advanced-panel {
  border: 1px solid var(--border);
  border-radius: 12px;
  background: linear-gradient(180deg, #ffffff 0%, #fafcff 100%);
}

.form-section {
  padding: 20px;
}

.slim-section {
  padding: 18px;
}

.field-note,
.artifact-note {
  padding: 14px 16px;
  border-radius: 10px;
  background: rgba(83, 58, 253, 0.05);
  border: 1px solid rgba(83, 58, 253, 0.08);
  font-size: 0.98rem;
}

.advanced-panel {
  overflow: hidden;
}

.advanced-panel summary {
  list-style: none;
  cursor: pointer;
  padding: 18px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  color: var(--heading);
  font-weight: 600;
}

.advanced-panel summary::-webkit-details-marker {
  display: none;
}

.advanced-panel summary small {
  color: var(--body);
  font-weight: 400;
}

.advanced-panel[open] summary {
  border-bottom: 1px solid var(--border);
  background: rgba(83, 58, 253, 0.04);
}

.advanced-panel-body {
  padding: 18px;
}

.conditional-fields.is-hidden {
  display: none;
}

.stats-strip {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 20px;
  margin-bottom: 28px;
}

.inversion-stats {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.stats-card {
  background: linear-gradient(180deg, #ffffff 0%, #f8fbff 100%);
  padding: 20px 22px;
}

.stats-card strong {
  display: block;
  color: var(--heading);
  margin-top: 8px;
  font-size: 1.7rem;
  font-weight: 400;
  letter-spacing: -0.04em;
}

.dashboard-layout,
.inversion-layout,
.inversion-top-grid {
  align-items: start;
}

.result-stack {
  display: grid;
  gap: 24px;
  align-content: start;
}

.data-preview,
.chart-shell {
  overflow: auto;
}

table {
  width: 100%;
  border-collapse: collapse;
  background: transparent;
}

th,
td {
  text-align: left;
  padding: 13px 12px;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}

th {
  color: var(--label);
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

tbody tr:hover {
  background: rgba(83, 58, 253, 0.03);
}

.status-pill {
  display: inline-flex;
  padding: 4px 10px;
  border-radius: 999px;
  background: var(--purple-bg);
  color: var(--purple);
  font-size: 0.76rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.result-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.result-grid dt {
  margin-bottom: 6px;
}

.result-grid dd {
  margin: 0;
  color: var(--heading);
  font-size: 1.24rem;
  font-weight: 500;
  letter-spacing: -0.03em;
}

.compact-grid dt,
.compact-grid dd {
  font-size: 0.96rem;
}

.chart-shell svg,
.cc-svg,
.chart-svg,
.theory-svg {
  width: 100%;
  height: auto;
  display: block;
}

.chart-shell-labeled {
  display: grid;
  grid-template-columns: 44px minmax(0, 1fr);
  align-items: center;
  gap: 6px;
}

.chart-y-label {
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--heading);
  font-size: 0.94rem;
  min-height: 320px;
  transform: rotate(-90deg);
  white-space: nowrap;
}

.chart-x-label {
  margin-top: 8px;
  text-align: center;
  color: var(--heading);
  font-size: 0.94rem;
}

.chart-axis {
  stroke: #7d90a7;
  stroke-width: 1.4;
}

.chart-grid {
  stroke: #e5edf5;
  stroke-width: 1;
}

.chart-fitted {
  stroke: var(--purple);
  stroke-width: 2.8;
}

.chart-point {
  fill: var(--ruby);
  stroke: #fff;
  stroke-width: 1.5;
}

.chart-label,
.chart-tick {
  fill: #5c6f84;
  font-size: 12px;
  font-variant-numeric: tabular-nums;
}

.cc-initial {
  stroke: var(--ruby);
  stroke-width: 3;
}

.cc-final {
  stroke: var(--purple);
  stroke-width: 3;
}

.cc-minimum {
  fill: var(--heading);
}

.cc-guide {
  stroke: #7d90a7;
  stroke-width: 1.4;
  stroke-dasharray: 5 4;
}

.cc-guide-fill {
  fill: #7d90a7;
}

.cc-label {
  fill: var(--heading);
  font-size: 15px;
  font-weight: 600;
}

.cc-math,
.cc-axis-label {
  fill: var(--body);
  font-size: 14px;
}

.theory-hero {
  display: grid;
  grid-template-columns: minmax(0, 1.3fr) minmax(320px, 0.8fr);
  gap: 24px;
  margin-bottom: 28px;
}

.theory-hero-copy {
  background: var(--brand-gradient);
  color: #fff;
  border-radius: var(--radius-lg);
  padding: 38px;
  box-shadow: var(--shadow-card);
}

.theory-hero-copy .eyebrow {
  color: var(--purple-light);
}

.theory-hero-copy .hero-text,
.theory-hero-copy h1 {
  color: #fff;
}

.theory-hero-copy .hero-text {
  color: rgba(255, 255, 255, 0.76);
  margin-top: 18px;
}

.theory-hero-panel {
  display: grid;
  gap: 14px;
  align-content: start;
}

.theory-pill {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 12px 16px;
  color: var(--heading);
  box-shadow: var(--shadow-sm);
}

.theory-section {
  display: grid;
  gap: 22px;
  margin-bottom: 28px;
}

.theory-section-head {
  display: grid;
  gap: 8px;
}

.theory-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px;
}

.theory-grid.reverse {
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.1fr);
}

.theory-note {
  margin-top: 18px;
  padding: 14px 16px;
  border-radius: 10px;
  background: rgba(83, 58, 253, 0.05);
  border: 1px solid rgba(83, 58, 253, 0.08);
}

.theory-note ul {
  margin-top: 10px;
  padding-left: 20px;
}

.theory-figure-card img,
.theory-image {
  width: 100%;
  height: auto;
  display: block;
  border-radius: 10px;
  border: 1px solid var(--border);
}

.theory-quad {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 40px minmax(0, 1fr) 40px minmax(0, 1fr) 40px minmax(0, 1fr);
  gap: 16px;
  align-items: stretch;
}

.flow-operator {
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--purple);
  font-size: 1.8rem;
  font-weight: 300;
}

.mini-formula {
  color: var(--body);
  font-size: 0.95rem;
  margin-top: 6px;
}

.theory-mini-figure {
  margin-top: 12px;
}

.inversion-flow {
  display: grid;
  gap: 14px;
}

.flow-step {
  display: grid;
  gap: 6px;
  padding: 18px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: linear-gradient(180deg, #ffffff 0%, #f8fbff 100%);
}

.flow-step strong {
  color: var(--heading);
}

.flow-index {
  color: var(--purple);
  font-size: 0.84rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.flow-arrow {
  color: var(--purple);
  font-size: 1.6rem;
  text-align: center;
}

.theory-axis {
  stroke: #8ca0b6;
  stroke-width: 2;
}

.curve-final {
  fill: none;
  stroke: var(--purple);
  stroke-width: 4;
}

.fit-reference-line {
  stroke: #9eb0c1;
  stroke-width: 2.2;
  stroke-dasharray: 8 7;
}

.state-dot-alt {
  fill: var(--ruby);
}

.svg-label,
.chart-title {
  fill: var(--heading);
  font-size: 14px;
  font-weight: 500;
}

ul,
ol {
  padding-left: 20px;
}

li + li {
  margin-top: 8px;
}

img {
  max-width: 100%;
}

@media (max-width: 1180px) {
  .lab-hero,
  .theory-hero,
  .grid-two,
  .theory-grid,
  .theory-grid.reverse,
  .workspace-grid {
    grid-template-columns: 1fr;
  }

  .theory-quad {
    grid-template-columns: 1fr;
  }

  .flow-operator {
    min-height: 24px;
  }

  .stats-strip,
  .inversion-stats {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .inline-fields-3,
  .inline-fields-4 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 900px) {
  .site-header {
    flex-wrap: wrap;
    height: auto;
    padding-top: 12px;
    padding-bottom: 12px;
  }

  .nav {
    margin-left: 0;
    width: 100%;
    order: 3;
  }

  .page-shell {
    padding-top: 132px;
  }

  .content-header {
    align-items: flex-start;
    flex-direction: column;
  }

  .inline-fields,
  .inline-fields-3,
  .inline-fields-4,
  .stats-strip,
  .inversion-stats,
  .result-grid,
  .data-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 640px) {
  body {
    font-size: 16px;
  }

  .site-header,
  .page-shell {
    padding-left: 18px;
    padding-right: 18px;
  }

  .page-shell {
    padding-bottom: 48px;
  }

  .lab-copy,
  .hero-panel,
  .workspace-card,
  .form-card,
  .table-card,
  .info-card,
  .result-card,
  .stats-card,
  .theory-hero-copy {
    padding: 20px;
  }

  h1,
  .content-header h1,
  .form-card h1 {
    font-size: 2.1rem;
  }

  h2 {
    font-size: 1.5rem;
  }

  th,
  td {
    padding: 10px 8px;
  }
}