:root {
  color-scheme: light;
  --bg: #f5f7fb;
  --surface: #ffffff;
  --surface-2: #eef3f8;
  --ink: #111827;
  --muted: #607086;
  --line: #d8e0ea;
  --brand: #0f766e;
  --brand-2: #2563eb;
  --accent: #f59e0b;
  --danger: #b91c1c;
  --shadow: 0 18px 50px rgba(17, 24, 39, 0.1);
  --radius: 8px;
}

[data-theme="dark"] {
  color-scheme: dark;
  --bg: #0b1018;
  --surface: #121a26;
  --surface-2: #172233;
  --ink: #f8fafc;
  --muted: #a8b3c4;
  --line: #29364a;
  --brand: #2dd4bf;
  --brand-2: #60a5fa;
  --accent: #fbbf24;
  --danger: #f87171;
  --shadow: 0 18px 50px rgba(0, 0, 0, 0.32);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 140px;
}

body {
  min-width: 320px;
  margin: 0;
  background:
    radial-gradient(circle at top left, rgba(37, 99, 235, 0.12), transparent 30rem),
    linear-gradient(135deg, var(--bg), var(--surface-2));
  color: var(--ink);
  font-family:
    Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    sans-serif;
  line-height: 1.5;
}

button,
input,
select {
  font: inherit;
}

button,
a,
summary {
  touch-action: manipulation;
}

button {
  cursor: pointer;
}

a {
  color: inherit;
}

code {
  padding: 0.12rem 0.3rem;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--surface-2);
}

:focus-visible {
  outline: 3px solid color-mix(in srgb, var(--brand-2), transparent 40%);
  outline-offset: 3px;
}

.skip-link {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 100;
  transform: translateY(-160%);
  padding: 10px 14px;
  border-radius: var(--radius);
  background: var(--ink);
  color: var(--bg);
  text-decoration: none;
}

.skip-link:focus {
  transform: translateY(0);
}

.app-shell {
  display: grid;
  grid-template-columns: clamp(220px, 19vw, 280px) minmax(0, 1fr);
  min-height: 100vh;
}

.sidebar {
  position: sticky;
  top: 0;
  height: 100vh;
  display: flex;
  flex-direction: column;
  gap: 22px;
  padding: 22px;
  border-right: 1px solid var(--line);
  background: color-mix(in srgb, var(--surface), transparent 4%);
  backdrop-filter: blur(20px);
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  min-height: 48px;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  width: 46px;
  height: 46px;
  place-items: center;
  border-radius: var(--radius);
  background: linear-gradient(135deg, var(--brand), var(--brand-2));
  color: white;
  font-size: 1.6rem;
  font-weight: 900;
}

.brand strong,
.brand small {
  display: block;
}

.brand small,
.eyebrow,
.metric-card span,
.result-display span {
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0;
  text-transform: uppercase;
}

.nav-list {
  display: grid;
  gap: 6px;
}

.nav-list a {
  display: flex;
  align-items: center;
  gap: 10px;
  min-height: 44px;
  padding: 10px 12px;
  border-radius: var(--radius);
  color: var(--muted);
  font-weight: 750;
  text-decoration: none;
}

.nav-list a:hover,
.nav-list a.active {
  background: color-mix(in srgb, var(--brand), transparent 88%);
  color: var(--ink);
}

.sidebar-card {
  margin-top: auto;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface-2);
}

.sidebar-card p,
.sidebar-card strong {
  display: block;
  margin: 0 0 8px;
}

.main-area {
  min-width: 0;
  width: 100%;
  overflow-x: clip;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  gap: 16px;
  justify-content: space-between;
  min-height: 82px;
  padding: 16px clamp(18px, 4vw, 42px);
  border-bottom: 1px solid var(--line);
  background: color-mix(in srgb, var(--bg), transparent 6%);
  backdrop-filter: blur(18px);
}

.topbar h1,
h2,
p {
  margin-top: 0;
}

.topbar h1 {
  margin-bottom: 0;
  font-size: clamp(1.35rem, 2.4vw, 2rem);
  line-height: 1.12;
  overflow-wrap: anywhere;
}

.topbar-actions,
.hero-actions,
.toolbar,
.inline-form {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.topbar-actions {
  flex: 0 1 auto;
  max-width: 100%;
}

#main {
  padding: clamp(18px, 4vw, 42px);
  max-width: 1500px;
  margin: 0 auto;
}

.view {
  display: none;
  scroll-margin-top: 140px;
}

.view.active {
  display: block;
}

.dashboard-grid,
.section-grid,
.calculator-layout,
.settings-grid,
.docs-grid {
  display: grid;
  gap: 18px;
}

.dashboard-grid {
  grid-template-columns: minmax(0, 1.5fr) repeat(3, minmax(140px, 0.45fr));
}

.section-grid,
.calculator-layout,
.settings-grid {
  grid-template-columns: minmax(0, 1.25fr) minmax(280px, 0.75fr);
  margin-top: 18px;
}

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

.hero-panel,
.panel,
.metric-card {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: color-mix(in srgb, var(--surface), transparent 2%);
  box-shadow: var(--shadow);
}

.hero-panel {
  padding: clamp(24px, 4vw, 38px);
  background:
    linear-gradient(135deg, color-mix(in srgb, var(--brand), transparent 82%), transparent),
    var(--surface);
}

.hero-panel h2 {
  max-width: 16ch;
  margin-bottom: 16px;
  font-size: clamp(2.1rem, 4.6vw, 4.8rem);
  line-height: 1.02;
  overflow-wrap: normal;
}

.hero-panel p {
  max-width: 720px;
  color: var(--muted);
  font-size: 1.08rem;
}

.panel,
.metric-card {
  padding: 18px;
}

.metric-card {
  display: grid;
  align-content: space-between;
  min-height: 170px;
}

.metric-card strong {
  display: block;
  font-size: clamp(2.2rem, 5vw, 3.5rem);
  line-height: 1;
}

.metric-card p,
.panel p {
  color: var(--muted);
}

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

.panel-header.compact {
  margin-top: 18px;
}

.panel-header h2 {
  margin-bottom: 0;
  font-size: clamp(1.25rem, 2.5vw, 1.8rem);
}

.button,
.icon-button,
.keypad button,
.memory-row button {
  min-height: 44px;
  border: 0;
  border-radius: var(--radius);
  font-weight: 850;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 14px;
  background: var(--brand);
  color: #ffffff;
  text-decoration: none;
}

.button.secondary {
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--ink);
}

.button.danger {
  background: var(--danger);
  color: white;
}

.button.small {
  width: 100%;
  min-height: 38px;
}

.icon-button {
  display: inline-grid;
  width: 44px;
  place-items: center;
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--ink);
}

#menu-button {
  display: none;
}

label {
  display: grid;
  gap: 8px;
  color: var(--muted);
  font-size: 0.88rem;
  font-weight: 800;
}

input,
select {
  width: 100%;
  min-height: 44px;
  padding: 10px 12px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  color: var(--ink);
}

.quick-form {
  display: grid;
  gap: 12px;
}

.inline-form input {
  flex: 1 1 240px;
}

.result-display {
  display: grid;
  gap: 6px;
  margin-top: 16px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface-2);
}

.result-display strong,
.calc-result {
  overflow-wrap: anywhere;
  font-size: clamp(1.8rem, 5vw, 3.2rem);
  line-height: 1.1;
}

.chip-list,
.reference-grid,
.action-grid {
  display: grid;
  gap: 10px;
}

.chip-list {
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
}

.chip,
.reference-grid span,
.tip-box {
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface-2);
}

.chip {
  text-align: left;
}

.calculator {
  display: grid;
  gap: 14px;
}

.calc-screen {
  display: grid;
  gap: 10px;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface-2);
}

.expression-input {
  min-height: 54px;
  font-size: 1.2rem;
}

.calc-result {
  min-height: 58px;
  color: var(--brand);
  font-weight: 900;
}

.error-message {
  min-height: 24px;
  margin: 0;
  color: var(--danger);
  font-weight: 800;
}

.memory-row,
.keypad {
  display: grid;
  gap: 8px;
}

.memory-row {
  grid-template-columns: repeat(5, minmax(0, 1fr));
}

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

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

.keypad button,
.memory-row button,
.chip {
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--ink);
}

.keypad button:hover,
.memory-row button:hover,
.chip:hover {
  background: color-mix(in srgb, var(--brand-2), transparent 88%);
}

.keypad .equals {
  background: var(--brand-2);
  color: white;
}

.tip-box {
  margin-top: 16px;
}

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

.converter-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 12px;
}

.currency-panel {
  display: none;
}

.currency-panel.active {
  display: block;
}

.currency-rates {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 10px;
  margin-bottom: 12px;
}

.item-list {
  display: grid;
  gap: 10px;
}

.empty-state,
.item {
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface-2);
}

.item {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 12px;
  align-items: center;
}

.item strong,
.item span {
  display: block;
  overflow-wrap: anywhere;
}

.item span {
  color: var(--muted);
}

.item-actions {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.item-actions button {
  min-height: 36px;
  padding: 7px 10px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  color: var(--ink);
  font-weight: 800;
}

.file-button {
  position: relative;
  overflow: hidden;
}

.file-button input {
  position: absolute;
  inset: 0;
  opacity: 0;
}

.toggle-line {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 12px 0;
  border-bottom: 1px solid var(--line);
  color: var(--ink);
}

.toggle-line input,
.toggle-line select {
  width: min(220px, 50%);
}

details {
  padding: 12px 0;
  border-bottom: 1px solid var(--line);
}

summary {
  font-weight: 850;
  cursor: pointer;
}

.toast {
  position: fixed;
  right: 18px;
  bottom: 18px;
  z-index: 80;
  max-width: min(380px, calc(100vw - 36px));
  transform: translateY(140%);
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--ink);
  color: var(--bg);
  box-shadow: var(--shadow);
  transition: transform 180ms ease;
}

.toast.show {
  transform: translateY(0);
}

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

[data-reduce-motion="true"] *,
[data-reduce-motion="true"] *::before,
[data-reduce-motion="true"] *::after {
  scroll-behavior: auto !important;
  transition-duration: 0.01ms !important;
  animation-duration: 0.01ms !important;
}

@media (max-width: 1180px) {
  .app-shell {
    grid-template-columns: 224px minmax(0, 1fr);
  }

  .sidebar {
    gap: 14px;
    padding: 16px;
  }

  .brand {
    gap: 10px;
  }

  .brand-mark {
    width: 40px;
    height: 40px;
    font-size: 1.35rem;
  }

  .brand strong {
    font-size: 0.98rem;
    line-height: 1.15;
  }

  .nav-list a {
    min-height: 40px;
    padding: 8px 10px;
    font-size: 0.92rem;
  }

  .sidebar-card {
    padding: 12px;
  }

  .topbar {
    min-height: 74px;
    padding: 12px 20px;
  }

  #main {
    padding: 22px;
  }

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

  .hero-panel {
    grid-column: 1 / -1;
  }

  .hero-panel h2 {
    max-width: 22ch;
    font-size: clamp(2rem, 4.2vw, 3.7rem);
  }

  .metric-card {
    min-height: 142px;
  }
}

@media (max-width: 1040px) {
  .topbar {
    align-items: flex-start;
    flex-wrap: wrap;
  }

  .topbar > div:first-of-type {
    min-width: 0;
  }

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

  .section-grid,
  .calculator-layout,
  .settings-grid {
    grid-template-columns: 1fr;
  }

  .calculator-layout {
    max-width: 760px;
  }
}

@media (min-width: 921px) and (max-width: 1040px) {
  .dashboard-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .hero-panel {
    grid-column: 1 / -1;
  }
}

@media (max-width: 920px) {
  .app-shell,
  .section-grid,
  .calculator-layout,
  .settings-grid,
  .docs-grid,
  .converter-grid {
    grid-template-columns: 1fr;
  }

  #menu-button {
    display: inline-grid;
  }

  .sidebar {
    position: fixed;
    inset: 0 auto 0 0;
    z-index: 60;
    width: min(310px, 86vw);
    transform: translateX(-105%);
    transition: transform 180ms ease;
  }

  .sidebar.open {
    transform: translateX(0);
  }

  .topbar {
    align-items: flex-start;
  }

  .topbar-actions {
    justify-content: flex-end;
  }
}

@media (max-width: 680px) {
  body[data-view="calculator"],
  body[data-view="scientific"] {
    background: var(--bg);
  }

  .topbar {
    display: grid;
    grid-template-columns: auto 1fr;
    min-height: 62px;
    padding: 8px 12px;
  }

  .topbar .eyebrow {
    display: none;
  }

  .topbar h1 {
    font-size: 1.2rem;
  }

  .topbar-actions {
    grid-column: 1 / -1;
    justify-content: flex-start;
  }

  body[data-view="calculator"] .topbar-actions,
  body[data-view="scientific"] .topbar-actions {
    display: none;
  }

  body[data-view="calculator"] #main,
  body[data-view="scientific"] #main {
    min-height: calc(100svh - 62px);
    padding: 8px;
  }

  .dashboard-grid,
  .memory-row {
    grid-template-columns: 1fr;
  }

  body[data-view="calculator"] .calculator-layout,
  body[data-view="scientific"] .calculator-layout {
    gap: 10px;
    margin-top: 0;
  }

  body[data-view="calculator"] .calculator.panel,
  body[data-view="scientific"] .calculator.panel {
    min-height: calc(100svh - 78px);
    padding: 10px;
    gap: 8px;
    box-shadow: none;
  }

  body[data-view="calculator"] .calculator-layout > aside,
  body[data-view="scientific"] .calculator-layout > aside {
    box-shadow: none;
  }

  body[data-view="calculator"] .calc-screen,
  body[data-view="scientific"] .calc-screen {
    position: sticky;
    top: 70px;
    z-index: 12;
    gap: 6px;
    grid-template-rows: auto auto auto;
    padding: 10px;
    box-shadow: 0 10px 22px rgba(17, 24, 39, 0.08);
  }

  body[data-view="calculator"] .calc-screen label,
  body[data-view="scientific"] .calc-screen label {
    position: absolute;
    width: 1px;
    height: 1px;
    overflow: hidden;
    clip: rect(0 0 0 0);
    white-space: nowrap;
  }

  body[data-view="calculator"] .expression-input,
  body[data-view="scientific"] .expression-input {
    min-height: 34px;
    padding: 6px 10px;
    font-size: 1rem;
  }

  body[data-view="calculator"] .calc-result,
  body[data-view="scientific"] .calc-result {
    min-height: 54px;
    font-size: clamp(2.45rem, 13vw, 4.1rem);
    text-align: right;
  }

  body[data-view="calculator"] .error-message,
  body[data-view="scientific"] .error-message {
    min-height: 12px;
    font-size: 0.78rem;
  }

  body[data-view="calculator"] .memory-row {
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: 6px;
  }

  body[data-view="calculator"] .memory-row button {
    min-height: 34px;
    padding: 4px;
    font-size: 0.75rem;
  }

  .keypad,
  .scientific-pad {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    overflow-x: visible;
  }

  body[data-view="calculator"] .keypad,
  body[data-view="scientific"] .scientific-pad {
    align-self: end;
    gap: 6px;
  }

  body[data-view="calculator"] .keypad button,
  body[data-view="scientific"] .scientific-pad button {
    min-height: clamp(44px, 10.5svh, 58px);
    padding: 4px;
    font-size: clamp(1rem, 5vw, 1.35rem);
  }

  body[data-view="scientific"] .scientific-pad button {
    min-height: clamp(38px, 8.5svh, 50px);
    font-size: clamp(0.8rem, 4vw, 1.05rem);
  }

  .hero-panel h2 {
    max-width: 100%;
    font-size: clamp(2.1rem, 13vw, 3.4rem);
  }

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