:root {
  --blue-50: #e3f2fd;
  --blue-100: #d8ecfb;
  --primary-600: #0f766e;
  --primary-700: #115e59;
  --badge-bg: #7c3aed;
  --reset-bg: #f97316;
  --reset-hover: #ea580c;
  --calendar-soft: #ecfdf5;
  --calendar-line: #b7e4d8;
  --calendar-selected: #0f766e;
  --calendar-today: #f97316;
  --gray-50: #f8f9fa;
  --gray-100: #f1f3f5;
  --gray-200: #e9ecef;
  --gray-300: #dee2e6;
  --gray-500: #6c757d;
  --gray-700: #495057;
  --gray-900: #212529;
  --white: #ffffff;
}

* {
  box-sizing: border-box;
}

body {
  background: var(--white);
  color: var(--gray-900);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei", sans-serif;
  font-size: 16px;
  line-height: 1.5;
  margin: 0;
}

a {
  color: var(--primary-600);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

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

h1,
h2 {
  font-size: 1.15rem;
  line-height: 1.35;
}

hr {
  border: 0;
  border-top: 1px solid var(--gray-300);
  margin: 1rem 0;
}

.page-shell {
  margin: 0 auto;
  max-width: 1140px;
  padding: 0 15px;
}

.navbar {
  align-items: center;
  background: var(--blue-50);
  display: flex;
  gap: 16px;
  justify-content: space-between;
  margin-top: 8px;
  min-height: 66px;
  padding: 8px 16px;
}

.navbar-brand {
  align-items: center;
  color: var(--gray-900);
  display: inline-flex;
  font-size: 1.1rem;
  font-weight: 600;
  gap: 10px;
}

.navbar-brand:hover {
  text-decoration: none;
}

.brand-icon {
  align-items: center;
  background: var(--primary-600);
  border-radius: 8px;
  color: var(--white);
  display: inline-flex;
  font-weight: 700;
  height: 44px;
  justify-content: center;
  width: 44px;
}

.nav-links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.nav-links a {
  color: var(--gray-700);
  font-size: 0.95rem;
}

.intro-card {
  background: var(--gray-50);
  border: 1px solid var(--blue-100);
  margin-top: 0.75rem;
  padding: 1rem;
}

.intro-card p {
  color: var(--gray-500);
  margin-bottom: 0;
}

.tool-layout {
  display: grid;
  gap: 1rem;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin-top: 0.75rem;
}

.card {
  background: var(--gray-50);
  border: 1px solid var(--blue-100);
  min-width: 0;
}

.card-body {
  padding: 1.25rem;
}

.card h2 {
  align-items: center;
  display: flex;
  gap: 0.45rem;
  margin-bottom: 0.45rem;
}

.badge {
  background: var(--badge-bg);
  border-radius: 0.25rem;
  color: var(--white);
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 700;
  line-height: 1;
  padding: 0.25em 0.45em;
}

.sub-title,
.help-text {
  color: var(--gray-500);
  font-size: 0.95rem;
}

.sub-title {
  margin-bottom: 0;
}

.help-text {
  margin-bottom: 0;
}

.stack-form {
  display: grid;
  gap: 0.85rem;
}

fieldset {
  border: 0;
  margin: 0;
  padding: 0;
}

legend {
  color: var(--gray-700);
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 0.4rem;
  padding: 0;
}

.field-row {
  display: grid;
  gap: 0.35rem;
  margin-bottom: 0.35rem;
}

.field-row:last-child {
  margin-bottom: 0;
}

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

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

label {
  align-items: stretch;
  display: flex;
  min-width: 0;
}

label > span,
.result-field > span,
.result-grid span {
  align-items: center;
  background: var(--gray-200);
  border: 1px solid var(--gray-300);
  color: var(--gray-700);
  display: inline-flex;
  flex: 0 0 auto;
  justify-content: center;
  min-height: 38px;
  padding: 0.375rem 0.75rem;
  white-space: nowrap;
}

input,
select,
output {
  background: var(--white);
  border: 1px solid var(--gray-300);
  color: var(--gray-900);
  display: block;
  font: inherit;
  min-height: 38px;
  min-width: 0;
  padding: 0.375rem 0.75rem;
  text-align: center;
  width: 100%;
}

input,
select {
  color: var(--primary-700);
}

input:focus,
select:focus {
  border-color: #5eead4;
  box-shadow: 0 0 0 0.2rem rgba(15, 118, 110, 0.16);
  outline: 0;
}

.full-field {
  display: grid;
  grid-template-columns: auto 1fr;
}

.button-row {
  display: flex;
  gap: 0.75rem;
  justify-content: center;
  padding: 0.75rem 0;
}

button {
  background: var(--primary-600);
  border: 1px solid var(--primary-600);
  border-radius: 0.25rem;
  color: var(--white);
  cursor: pointer;
  font: inherit;
  min-height: 38px;
  padding: 0.375rem 0.95rem;
}

button:hover {
  background: var(--primary-700);
  border-color: var(--primary-700);
}

.button-secondary {
  background: var(--reset-bg);
  border-color: var(--reset-bg);
  color: var(--white);
}

.button-secondary:hover {
  background: var(--reset-hover);
  border-color: var(--reset-hover);
}

.button-light {
  background: var(--calendar-soft);
  border-color: var(--calendar-line);
  color: var(--primary-700);
}

.button-light:hover {
  background: #ccfbf1;
  border-color: #99f6e4;
  color: var(--primary-700);
}

.result-field {
  display: grid;
  grid-template-columns: auto 1fr;
}

output {
  color: var(--primary-700);
  font-weight: 600;
}

.result-grid {
  display: grid;
  gap: 0.5rem;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.result-grid label {
  display: grid;
  grid-template-columns: auto 1fr;
}

.unit-list {
  color: var(--gray-700);
  line-height: 1.8;
  margin: 0;
  padding-left: 1.25rem;
}

.info-card p {
  color: var(--gray-700);
  text-indent: 2em;
}

.calendar-card {
  background: linear-gradient(180deg, #ffffff 0%, #f8fffc 100%);
}

.calendar-badge {
  background: var(--calendar-selected);
}

.calendar-toolbar {
  align-items: center;
  display: grid;
  gap: 0.75rem;
  grid-template-columns: 42px 1fr 42px;
  margin-bottom: 0.75rem;
}

.calendar-title {
  align-items: center;
  display: flex;
  gap: 0.5rem;
  justify-content: center;
}

.calendar-title label {
  display: grid;
  grid-template-columns: minmax(62px, 86px) auto;
}

.calendar-title input {
  border-color: var(--calendar-line);
  color: var(--primary-700);
  font-weight: 700;
  min-height: 42px;
  padding-left: 0.35rem;
  padding-right: 0.35rem;
}

.calendar-title span {
  background: var(--calendar-soft);
  border-color: var(--calendar-line);
  color: var(--primary-700);
  min-height: 42px;
}

.calendar-nav {
  background: var(--white);
  border: 1px solid var(--calendar-line);
  color: var(--primary-700);
  font-size: 1.45rem;
  font-weight: 700;
  min-height: 42px;
  padding: 0;
}

.calendar-nav:hover {
  background: var(--calendar-soft);
  border-color: var(--calendar-selected);
  color: var(--primary-700);
}

.calendar-actions {
  display: grid;
  gap: 0.6rem;
  grid-template-columns: 120px 1fr;
  margin-bottom: 0.8rem;
}

.calendar-actions output {
  border-color: var(--calendar-line);
  color: var(--primary-700);
}

.calendar-weekdays,
.calendar-grid {
  display: grid;
  gap: 0.35rem;
  grid-template-columns: repeat(7, minmax(0, 1fr));
}

.calendar-weekdays {
  color: var(--gray-500);
  font-size: 0.9rem;
  font-weight: 700;
  margin-bottom: 0.35rem;
  text-align: center;
}

.calendar-day {
  align-items: center;
  aspect-ratio: 1;
  background: var(--white);
  border: 1px solid var(--gray-300);
  border-radius: 0.45rem;
  color: var(--gray-700);
  display: inline-flex;
  font-weight: 600;
  justify-content: center;
  min-height: auto;
  padding: 0;
}

.calendar-day:hover {
  background: var(--calendar-soft);
  border-color: var(--calendar-selected);
  color: var(--primary-700);
}

.calendar-day.is-muted {
  background: #f6f7f8;
  color: #adb5bd;
}

.calendar-day.is-weekend {
  background: #fff7ed;
  border-color: #fed7aa;
}

.calendar-day.is-weekend.is-muted {
  background: #faf7f3;
  border-color: #eee1d3;
  color: #b8a99a;
}

.calendar-day.is-today {
  border-color: var(--calendar-today);
  box-shadow: inset 0 0 0 2px rgba(249, 115, 22, 0.2);
  color: var(--calendar-today);
}

.calendar-day.is-selected {
  background: var(--calendar-selected);
  border-color: var(--calendar-selected);
  color: var(--white);
}

.calendar-day.is-selected.is-today {
  box-shadow: inset 0 0 0 2px rgba(255, 255, 255, 0.42);
}

.faq-card {
  margin-top: 1rem;
}

details {
  border-top: 1px solid var(--gray-300);
  padding: 0.8rem 0;
}

details:first-of-type {
  border-top: 0;
}

summary {
  cursor: pointer;
  font-weight: 600;
}

details p {
  color: var(--gray-700);
  margin: 0.65rem 0 0;
}

.links-panel {
  margin-top: 1rem;
}

.tabs {
  border-bottom: 1px solid var(--gray-300);
}

.tab {
  border: 1px solid var(--gray-300);
  border-bottom: 0;
  color: var(--gray-700);
  display: inline-block;
  padding: 0.5rem 1rem;
}

.tab.active {
  background: var(--white);
  color: var(--gray-900);
}

.friend-links {
  color: darkgray;
  font-size: 0.95rem;
  padding: 0.75rem 0.5rem;
}

.friend-links a {
  color: darkgray;
  display: inline-block;
  margin: 0 0.9rem 0.45rem 0;
}

.footer {
  color: darkgray;
  font-size: 0.95rem;
  line-height: 1.6;
  padding-bottom: 2rem;
  padding-top: 2rem;
  text-align: center;
}

.footer a {
  color: darkgray;
}

@media (max-width: 900px) {
  .tool-layout,
  .result-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 640px) {
  .navbar {
    align-items: flex-start;
    flex-direction: column;
  }

  .three-col,
  .four-col {
    grid-template-columns: 1fr;
  }

  .field-row {
    gap: 0.5rem;
  }

  .button-row {
    flex-direction: column;
  }

  button {
    width: 100%;
  }

  .calendar-actions {
    grid-template-columns: 1fr;
  }

  .calendar-title {
    gap: 0.35rem;
  }

  .calendar-title label {
    grid-template-columns: minmax(50px, 1fr) auto;
  }
}