* {
  box-sizing: border-box;
}

:root {
  --page: #f4f6f5;
  --surface: #ffffff;
  --surface-muted: #eef2f0;
  --ink: #0b130f;
  --muted: #6c7e75;
  --line: #e9efef;
  --line-strong: rgba(11, 19, 15, 0.12);
  --brand: #072f1f;
  --brand-soft: #174f2d;
  --accent: #d97706;
  --success: #15803d;
  --success-soft: #dcfce7;
  --danger: #b91c1c;
  --danger-soft: #fee2e2;
  --sidebar: #051c12;
  --sidebar-ink: #f3faf6;
  --radius-control: 0.5rem;
  --radius-card: 1rem;
  --shadow-soft: 0 10px 30px rgba(11, 19, 15, 0.04);
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1), 0 1px 2px rgba(0, 0, 0, 0.06);
  --ring: 0 0 0 3px rgba(23, 79, 45, 0.2);
  font-size: 16px;
}

body {
  margin: 0;
  padding: 1.5rem;
  background: var(--page);
  color: var(--ink);
  font-family: "Segoe UI", Arial, Helvetica, sans-serif;
  line-height: 1.5;
}

a {
  color: var(--brand-soft);
}

a:focus-visible,
button:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible,
summary:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 3px;
}

.page {
  width: 100%;
  max-width: 72rem;
  margin: 0 auto;
}

.lesson-nav {
  margin: 0 0 1.5rem;
  padding: 0.75rem;
  background: var(--surface-muted);
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  border: 1px solid var(--line);
  border-radius: 0.75rem;
}

.lesson-nav a {
  flex: 1 1 8rem;
  padding: 0.55rem 0.7rem;
  background: var(--surface);
  border: 1px solid #a9bdaf;
  border-radius: 0.5rem;
  font-size: 0.85rem;
  font-weight: 700;
  text-align: center;
  text-decoration: none;
}

.lesson-nav a:hover,
.lesson-nav a[aria-current="page"] {
  background: var(--brand-soft);
  color: #ffffff;
}

.page-header {
  margin: 0 0 1.5rem;
  padding: 2rem;
  background: var(--brand);
  border-radius: var(--radius-card);
  color: #ffffff;
}

.page-header h1,
.page-header p {
  margin: 0;
}

.page-header p {
  margin-top: 0.5rem;
  color: #dceade;
}

.panel,
.panel-alt {
  margin: 0 0 1.25rem;
  padding: 1.25rem;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-card);
}

.panel-alt {
  background: var(--surface-muted);
}

.panel h2,
.panel-alt h2 {
  margin: 0 0 0.5rem;
  color: var(--brand-soft);
}

.panel p,
.panel-alt p {
  margin: 0 0 0.75rem;
}

.demo-grid {
  display: grid;
  gap: 1rem;
  grid-template-columns: 1fr;
}

@media (min-width: 44rem) {
  .demo-grid.two {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

/* Elevation cards */
.card {
  padding: 1.5rem;
  background: var(--surface);
  border-radius: var(--radius-card);
  color: var(--ink);
}

.card-border {
  border: 1px solid var(--line);
  box-shadow: none;
}

.card-soft {
  border: 0;
  box-shadow: var(--shadow-soft);
}

.card-hairline {
  border: 1px solid var(--line);
  box-shadow: var(--shadow-sm);
}

.card h3 {
  margin: 0 0 0.35rem;
  font-size: 1rem;
}

.card p {
  margin: 0;
  color: var(--muted);
  font-size: 0.9rem;
}

.radius-scale {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.radius-swatch {
  width: 4.5rem;
  height: 4.5rem;
  background: var(--brand-soft);
  color: #ffffff;
  display: grid;
  place-items: center;
  font-size: 0.75rem;
  font-weight: 700;
}

/* Metric cards */
.metric-card {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  min-height: 10rem;
}

.metric-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
}

.metric-label {
  color: var(--muted);
  font-size: 0.9rem;
}

.metric-icon {
  width: 2.5rem;
  height: 2.5rem;
  display: grid;
  place-items: center;
  background: var(--surface-muted);
  border-radius: 0.75rem;
  color: var(--brand-soft);
  font-weight: 800;
}

.metric-value {
  margin: 0;
  font-size: 1.85rem;
  font-weight: 800;
  line-height: 1.1;
}

.trend {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  padding: 0.2rem 0.55rem;
  border-radius: 999px;
  font-size: 0.8rem;
  font-weight: 700;
}

.trend-up {
  background: var(--success-soft);
  color: var(--success);
}

.trend-down {
  background: var(--danger-soft);
  color: var(--danger);
}

.metric-card-featured {
  background: var(--brand);
  color: #ffffff;
}

.metric-card-featured .metric-label,
.metric-card-featured .metric-value {
  color: #ffffff;
}

.metric-card-featured .metric-icon {
  background: rgba(255, 255, 255, 0.12);
  color: #ffffff;
}

.metric-card-featured .trend-up {
  background: rgba(255, 255, 255, 0.14);
  color: #bbf7d0;
}

/* Dashboard shell */
.shell {
  display: grid;
  min-height: 28rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-card);
  overflow: hidden;
  background: var(--page);
}

.shell-sidebar {
  display: none;
  padding: 1.25rem;
  background: var(--sidebar);
  color: var(--sidebar-ink);
}

.shell-brand {
  margin: 0 0 1.25rem;
  font-weight: 800;
}

.shell-nav {
  display: grid;
  gap: 0.35rem;
}

.shell-nav a {
  padding: 0.65rem 0.75rem;
  border-radius: 0.6rem;
  color: inherit;
  text-decoration: none;
}

.shell-nav a[aria-current="page"],
.shell-nav a:hover {
  background: rgba(255, 255, 255, 0.12);
}

.shell-main {
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.shell-topbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  padding: 1rem 1.25rem;
  background: var(--surface);
  border-bottom: 1px solid var(--line);
}

.shell-topbar h2 {
  margin: 0;
  font-size: 1.15rem;
}

.shell-topbar p {
  margin: 0.15rem 0 0;
  color: var(--muted);
  font-size: 0.85rem;
}

.ops-strip {
  display: grid;
  gap: 0.75rem;
  padding: 1rem 1.25rem;
  background: var(--surface-muted);
  border-bottom: 1px solid var(--line);
  grid-template-columns: 1fr;
}

.ops-item strong {
  display: block;
  font-size: 1.2rem;
}

.ops-item span {
  color: var(--muted);
  font-size: 0.85rem;
}

.shell-content {
  padding: 1.25rem;
}

@media (min-width: 52rem) {
  .shell {
    grid-template-columns: 14rem 1fr;
  }

  .shell-sidebar {
    display: block;
  }

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

/* Forms */
.form-stack {
  display: grid;
  gap: 1rem;
}

.form-row label,
.form-label {
  display: block;
  margin: 0 0 0.4rem;
  font-weight: 700;
  font-size: 0.9rem;
}

.help {
  margin: 0.35rem 0 0;
  color: var(--muted);
  font-size: 0.85rem;
}

.field,
.field-sm,
.field-lg,
select.field,
textarea.field {
  width: 100%;
  margin: 0;
  padding: 0.65rem 0.9rem;
  background: var(--surface);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-control);
  color: var(--ink);
  font: inherit;
  box-shadow: 0 1px 2px rgba(16, 24, 40, 0.05);
}

.field-sm {
  padding: 0.4rem 0.7rem;
  font-size: 0.875rem;
}

.field-lg {
  padding: 0.9rem 1rem;
  font-size: 1.05rem;
}

.field:focus,
.field-sm:focus,
.field-lg:focus {
  outline: none;
  border-color: #86a897;
  box-shadow: var(--ring);
}

.field:disabled,
.field[readonly] {
  background: var(--surface-muted);
  border-color: rgba(11, 19, 15, 0.06);
  color: var(--muted);
}

.form-horizontal {
  display: grid;
  gap: 1rem;
}

.form-horizontal .form-row {
  display: grid;
  gap: 0.35rem;
}

@media (min-width: 44rem) {
  .form-horizontal .form-row {
    grid-template-columns: 8rem 1fr;
    align-items: center;
    gap: 1rem;
  }

  .form-horizontal .form-row label {
    margin: 0;
  }

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

  .form-grid-fields .full {
    grid-column: 1 / -1;
  }
}

.form-inline {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  align-items: end;
}

.form-inline .form-row {
  flex: 1 1 10rem;
}

.form-inline-check {
  min-height: 2.5rem;
  align-items: center;
}

.address-grid {
  display: grid;
  gap: 1rem;
  grid-template-columns: 1fr;
}

@media (min-width: 44rem) {
  .address-grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 2.5fr) minmax(0, 2.5fr);
  }
}

.choice-fieldset {
  margin: 0;
  padding: 0;
  border: 0;
}

.choice-fieldset legend {
  margin: 0 0 0.5rem;
  font-weight: 700;
  font-size: 0.9rem;
}

.choice-stack {
  display: grid;
  gap: 0.5rem;
}

.choice-line {
  display: flex;
  align-items: center;
  gap: 0.55rem;
}

.choice-line label {
  margin: 0;
  font-weight: 400;
}

.choice-line input {
  width: auto;
  margin: 0;
}

.input-group {
  display: flex;
  flex-wrap: nowrap;
  width: 100%;
  align-items: stretch;
}

.input-group .field {
  flex: 1 1 auto;
  width: 1%;
  min-width: 0;
  border-radius: 0 var(--radius-control) var(--radius-control) 0;
}

.input-group-text {
  display: flex;
  align-items: center;
  padding: 0.65rem 0.85rem;
  background: var(--surface-muted);
  border: 1px solid var(--line-strong);
  border-right: 0;
  border-radius: var(--radius-control) 0 0 var(--radius-control);
  color: var(--ink);
  font-size: 0.9rem;
  font-weight: 700;
  white-space: nowrap;
}

.input-group .field:focus {
  position: relative;
  z-index: 1;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.5rem;
  padding: 0.55rem 1rem;
  background: var(--brand);
  border: 1px solid var(--brand);
  border-radius: var(--radius-control);
  color: #ffffff;
  font: inherit;
  font-weight: 700;
  cursor: pointer;
}

.btn-secondary {
  background: var(--surface);
  color: var(--ink);
  border-color: var(--line-strong);
}

/* Validation */
.field:user-valid {
  border-color: var(--success);
}

.field:user-invalid {
  border-color: var(--danger);
}

.feedback {
  margin: 0.35rem 0 0;
  font-size: 0.85rem;
}

.feedback-ok {
  color: var(--success);
}

.feedback-bad {
  color: var(--danger);
}

.demo-invalid .field {
  border-color: var(--danger);
}

.demo-valid .field {
  border-color: var(--success);
}

/* Floating labels */
.float-field {
  position: relative;
}

.float-field .field {
  padding-top: 1.25rem;
  padding-bottom: 0.55rem;
}

.float-field label {
  position: absolute;
  left: 0.9rem;
  top: 0.95rem;
  margin: 0;
  color: var(--muted);
  font-size: 0.95rem;
  font-weight: 600;
  pointer-events: none;
  transition: top 140ms ease, font-size 140ms ease, color 140ms ease;
}

.float-field .field:focus + label,
.float-field .field:not(:placeholder-shown) + label {
  top: 0.35rem;
  font-size: 0.7rem;
  color: var(--brand-soft);
}

.icon-field {
  position: relative;
}

.icon-field .field {
  padding-left: 2.5rem;
}

.icon-field .field-icon {
  position: absolute;
  left: 0.85rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--muted);
  font-weight: 700;
  pointer-events: none;
}

/* Dropzone */
.dropzone {
  position: relative;
  display: grid;
  place-items: center;
  gap: 0.35rem;
  min-height: 10rem;
  padding: 1.5rem;
  border: 2px dashed #a9bdaf;
  border-radius: var(--radius-card);
  background: var(--surface-muted);
  text-align: center;
}

.dropzone strong {
  color: var(--brand-soft);
}

.dropzone .field-file {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  opacity: 0;
  cursor: pointer;
}

/* Star rating */
.star-rating {
  display: flex;
  flex-direction: row-reverse;
  justify-content: flex-end;
  gap: 0.15rem;
}

.star-rating input {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  clip: rect(0 0 0 0);
  overflow: hidden;
}

.star-rating label {
  margin: 0;
  font-size: 1.75rem;
  line-height: 1;
  color: #cbd5d1;
  cursor: pointer;
}

.star-rating label:hover,
.star-rating label:hover ~ label,
.star-rating input:checked ~ label {
  color: var(--accent);
}

.star-rating input:focus-visible + label {
  outline: 3px solid var(--accent);
  outline-offset: 3px;
}

/* Wizard chrome */
.wizard {
  border: 1px solid var(--line);
  border-radius: var(--radius-card);
  background: var(--surface);
  overflow: hidden;
}

.wizard-steps {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  padding: 1rem 1.25rem;
  background: var(--surface-muted);
  border-bottom: 1px solid var(--line);
  list-style: none;
  margin: 0;
}

.wizard-steps li {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.35rem 0.65rem;
  border-radius: 999px;
  color: var(--muted);
  font-size: 0.85rem;
  font-weight: 700;
}

.wizard-steps .is-current {
  background: var(--brand);
  color: #ffffff;
}

.wizard-steps .is-done {
  background: var(--success-soft);
  color: var(--success);
}

.wizard-progress {
  height: 0.4rem;
  background: #dce8df;
}

.wizard-progress > span {
  display: block;
  width: 33%;
  height: 100%;
  background: var(--brand-soft);
}

.wizard-body {
  padding: 1.25rem;
}

.wizard-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  justify-content: flex-end;
  padding: 1rem 1.25rem;
  border-top: 1px solid var(--line);
}

.nested-well {
  padding: 1rem;
  background: var(--surface-muted);
  border: 1px solid var(--line);
  border-radius: var(--radius-card);
}

.nested-well .card {
  margin: 0;
}

.radius-6 { border-radius: 0.375rem; }
.radius-8 { border-radius: 0.5rem; }
.radius-16 { border-radius: 1rem; }
.radius-24 { border-radius: 1.5rem; }

.stack-gap {
  margin-top: 1rem;
}

.lesson-source {
  max-width: 72rem;
  margin: 0 auto 2rem;
  padding: 0 1.5rem;
}