:root {
  color-scheme: light;
  --surface: rgba(255,255,255,.94);
  --soft: #f3faf5;
  --text: #17372c;
  --muted: #63766e;
  --border: #c5ddcf;
  --green: #167057;
  --green-dark: #0c503e;
  --green-light: #dff3e8;
  --danger: #b42318;
  --shadow: 0 22px 58px rgba(24,73,55,.15);
}
* { box-sizing: border-box; }
body {
  margin: 0;
  min-height: 100vh;
  font-family: Inter, system-ui, -apple-system, "Segoe UI", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at 6% 4%, rgba(168,217,111,.30), transparent 26%),
    radial-gradient(circle at 94% 8%, rgba(105,200,158,.25), transparent 27%),
    linear-gradient(145deg, #dff5e8, #f4f8f2 55%, #edf5ef);
  background-attachment: fixed;
}
button, input { font: inherit; }
.container { width: min(1240px, calc(100% - 32px)); margin: 42px auto; }
.page-layout {
  display: grid;
  grid-template-columns: minmax(0,1fr) 230px;
  gap: 24px;
  align-items: start;
}
.card {
  background: var(--surface);
  border: 1px solid rgba(197,221,207,.9);
  border-radius: 24px;
  box-shadow: var(--shadow);
  padding: clamp(24px,4vw,46px);
}
.calculator-card { min-width: 0; }
h1 {
  margin: 0;
  padding-bottom: .18em;
  font-size: clamp(2.35rem,5vw,4.25rem);
  line-height: 1.2;
  letter-spacing: -.045em;
  color: var(--green-dark);
  overflow: visible;
}
.intro {
  max-width: 720px;
  margin: 6px 0 0;
  color: var(--muted);
  font-size: 1.08rem;
  line-height: 1.65;
}
.section { margin-top: 29px; padding: 0; border: 0; }
label, legend { font-weight: 800; }
legend { margin-bottom: 12px; }
.start-row { display: grid; grid-template-columns: 1fr auto; gap: 12px; margin-top: 10px; }
input[type="datetime-local"], input[type="number"] {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: #fff;
  color: var(--text);
  padding: 13px 14px;
  outline: none;
  box-shadow: 0 5px 16px rgba(24,73,55,.05);
}
input:hover { border-color: #8fc4aa; }
input:focus { border-color: var(--green); box-shadow: 0 0 0 4px rgba(22,112,87,.13); }
.hint { margin: 9px 0 0; color: var(--muted); font-size: .9rem; }
.operation-switch {
  display: inline-grid;
  grid-template-columns: 1fr 1fr;
  padding: 4px;
  border: 1px solid var(--border);
  border-radius: 13px;
  background: var(--soft);
}
.operation-switch label { cursor: pointer; }
.operation-switch input { position: absolute; opacity: 0; pointer-events: none; }
.operation-switch span {
  display: block;
  min-width: 125px;
  padding: 11px 20px;
  border-radius: 9px;
  color: var(--muted);
  text-align: center;
}
.operation-switch input:checked + span {
  color: #fff;
  background: linear-gradient(135deg,var(--green),var(--green-dark));
  box-shadow: 0 7px 17px rgba(12,80,62,.20);
}
.units-grid { display: grid; grid-template-columns: repeat(4,minmax(105px,1fr)); gap: 14px; }
.units-grid label { display: grid; gap: 7px; }
.actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 30px; }
button {
  border-radius: 12px;
  padding: 12px 19px;
  border: 1px solid transparent;
  cursor: pointer;
  font-weight: 800;
}
button:hover { transform: translateY(-1px); }
.primary {
  color: #fff;
  background: linear-gradient(135deg,var(--green),var(--green-dark));
  box-shadow: 0 10px 22px rgba(12,80,62,.20);
}
.secondary { color: var(--green-dark); background: #fff; border-color: var(--border); }
.secondary:hover { background: var(--soft); }
.error { color: var(--danger); font-weight: 700; margin: 16px 0 0; }
.result {
  margin-top: 32px;
  padding: 24px;
  border-radius: 17px;
  background: linear-gradient(135deg,var(--green-light),#f4fbf6);
  border: 1px solid #b7dbc7;
}
.result-label {
  margin: 0;
  color: var(--green);
  font-weight: 900;
  text-transform: uppercase;
  letter-spacing: .06em;
  font-size: .8rem;
}
.result-date {
  margin: 8px 0;
  font-weight: 900;
  font-size: clamp(1.45rem,3.6vw,2.25rem);
  line-height: 1.25;
  color: var(--green-dark);
}
.result-extra { margin: 0 0 18px; color: var(--muted); overflow-wrap: anywhere; }
.explanation {
  margin-top: 28px;
  padding: 15px 17px;
  border-radius: 14px;
  background: var(--soft);
  color: var(--muted);
  line-height: 1.65;
}
.explanation summary { cursor: pointer; color: var(--green-dark); font-weight: 800; }
.ad-column { position: sticky; top: 20px; }
.ad-link {
  display: block;
  border-radius: 16px;
  overflow: hidden;
  background: #fff;
  box-shadow: 0 16px 38px rgba(42,51,45,.16);
  border: 1px solid rgba(90,77,67,.16);
}
.ad-link img { display: block; width: 100%; height: auto; }
@media (max-width: 900px) {
  .page-layout { grid-template-columns: minmax(0,1fr) 190px; gap: 18px; }
  .units-grid { grid-template-columns: repeat(2,minmax(0,1fr)); }
}
@media (max-width: 700px) {
  .container { width: min(100% - 18px,1240px); margin: 18px auto; }
  .page-layout { grid-template-columns: 1fr; }
  .card { border-radius: 18px; padding: 23px 16px; }
  .start-row { grid-template-columns: 1fr; }
  .ad-column { position: static; width: min(260px,100%); margin: 0 auto; }
  .operation-switch { display: grid; width: 100%; }
  .operation-switch span { min-width: 0; }
  .actions { display: grid; }
  button { width: 100%; }
}


.difference-section {
  margin: 20px 0;
  padding-top: 18px;
  border-top: 1px solid rgba(22, 112, 87, .18);
}

.difference-heading {
  margin: 0 0 12px;
  font-weight: 850;
  color: var(--green-dark);
}

.difference-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(110px, 1fr));
  gap: 10px;
}

.difference-item {
  display: flex;
  flex-direction: column;
  min-width: 0;
  padding: 14px 12px;
  border: 1px solid rgba(22, 112, 87, .15);
  border-radius: 12px;
  background: rgba(255, 255, 255, .68);
}

.difference-number {
  font-size: clamp(1.25rem, 3vw, 1.75rem);
  line-height: 1.1;
  font-weight: 900;
  color: var(--green-dark);
  overflow-wrap: anywhere;
}

.difference-label {
  margin-top: 5px;
  color: var(--muted);
  font-size: .82rem;
  line-height: 1.25;
}

.difference-note {
  margin: 11px 0 0;
  color: var(--muted);
  font-size: .82rem;
  line-height: 1.45;
}

@media (max-width: 850px) {
  .difference-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}


.calculation-actions {
  align-items: stretch;
}

.calculation-actions .primary {
  min-width: 150px;
}

.add-button {
  background: linear-gradient(135deg, #16845f, #0c5a43);
}

.subtract-button {
  background: linear-gradient(135deg, #527c68, #315c49);
}

.add-button::before {
  content: "+";
  display: inline-block;
  margin-right: 8px;
  font-size: 1.15em;
  line-height: 0;
}

.subtract-button::before {
  content: "−";
  display: inline-block;
  margin-right: 8px;
  font-size: 1.15em;
  line-height: 0;
}

@media (max-width: 700px) {
  .calculation-actions .primary {
    min-width: 0;
  }
}


.result-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.calendar-section {
  margin-top: 22px;
  padding-top: 20px;
  border-top: 1px solid rgba(22, 112, 87, .18);
}

.calendar-heading {
  margin: 0 0 13px;
  color: var(--green-dark);
  font-weight: 900;
  font-size: 1.05rem;
}

.calendar-title-label {
  display: block;
  margin-bottom: 7px;
  font-size: .9rem;
}

.calendar-title-input {
  width: 100%;
  margin-bottom: 12px;
}

.calendar-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.calendar-button {
  min-width: 165px;
}

.google-calendar-button {
  color: #fff;
  background: linear-gradient(135deg, #167057, #0c503e);
  box-shadow: 0 9px 20px rgba(12, 80, 62, .18);
}

.google-calendar-button::before {
  content: "▣";
  display: inline-block;
  margin-right: 8px;
}

.calendar-note {
  margin: 11px 0 0;
  color: var(--muted);
  font-size: .82rem;
  line-height: 1.45;
}

@media (max-width: 700px) {
  .calendar-buttons {
    display: grid;
  }

  .calendar-button {
    min-width: 0;
  }
}


.share-button::before {
  content: "↗";
  display: inline-block;
  margin-right: 7px;
  font-size: 1.05em;
}

.calendar-note strong {
  color: var(--green-dark);
}