:root {
  /* Material 3 — Google Blue baseline (light) */
  --md-primary:           #0b57d0;
  --md-on-primary:        #ffffff;
  --md-primary-container: #d3e3fd;
  --md-on-primary-container: #001a41;

  --md-secondary:           #565e71;
  --md-on-secondary:        #ffffff;
  --md-secondary-container: #dae2f9;
  --md-on-secondary-container: #131c2b;

  --md-tertiary:           #006971;
  --md-on-tertiary:        #ffffff;
  --md-tertiary-container: #9eeff1;
  --md-on-tertiary-container: #002022;

  --md-error:           #b3261e;
  --md-on-error:        #ffffff;
  --md-error-container: #fadad6;
  --md-on-error-container: #410002;

  --md-background:      #fafbff;
  --md-on-background:   #1a1c1e;

  --md-surface:                 #fafbff;
  --md-surface-dim:             #d9dade;
  --md-surface-bright:          #fafbff;
  --md-surface-container-lowest:#ffffff;
  --md-surface-container-low:   #f4f4f8;
  --md-surface-container:       #eeeef2;
  --md-surface-container-high:  #e8e8ed;
  --md-surface-container-highest: #e2e3e7;
  --md-on-surface:              #1a1c1e;
  --md-on-surface-variant:      #44474f;

  --md-outline:         #74777f;
  --md-outline-variant: #c4c6d0;

  /* Heatmap palette (Google color spectrum) */
  --hue-green:   #34a853;
  --hue-stretch: #fbbc04;
  --hue-lunch:   #ff9800;
  --hue-red:     #ea4335;
  --hue-weekend: #9c27b0;
  --hue-holiday: #ec407a;

  /* Material 3 elevations */
  --md-elev-1: 0 1px 2px 0 rgba(0,0,0,0.06), 0 1px 3px 1px rgba(0,0,0,0.04);
  --md-elev-2: 0 1px 2px 0 rgba(0,0,0,0.08), 0 2px 6px 2px rgba(0,0,0,0.06);
  --md-elev-3: 0 1px 3px 0 rgba(0,0,0,0.10), 0 4px 8px 3px rgba(0,0,0,0.08);

  --md-radius-sm:   8px;
  --md-radius-md:  12px;
  --md-radius-lg:  16px;
  --md-radius-xl:  28px;
  --md-radius-pill: 999px;

  --font-body:    "Roboto", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-display: "Roboto Flex", "Roboto", system-ui, sans-serif;
  --font-mono:    "Roboto Mono", ui-monospace, "SF Mono", Menlo, monospace;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }

body {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.5;
  color: var(--md-on-background);
  background: var(--md-background);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

.material-symbols-outlined {
  font-variation-settings: "FILL" 0, "wght" 400, "GRAD" 0, "opsz" 24;
  font-size: 20px;
  line-height: 1;
  user-select: none;
  vertical-align: middle;
}

/* ---------- top app bar ---------- */

.app-bar {
  background: var(--md-surface);
  position: sticky;
  top: 0;
  z-index: 10;
  border-bottom: 1px solid var(--md-outline-variant);
}
.app-bar-inner {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 24px;
  height: 64px;
  display: flex;
  align-items: center;
  gap: 24px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: var(--md-on-surface);
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 22px;
  letter-spacing: 0;
}
.brand-mark {
  width: 40px;
  height: 40px;
  background: var(--md-primary);
  color: var(--md-on-primary);
  border-radius: var(--md-radius-md);
  display: grid;
  place-items: center;
}
.brand-mark .material-symbols-outlined { font-size: 24px; }
.brand-name { font-weight: 500; }
.brand-tagline {
  margin-left: auto;
  color: var(--md-on-surface-variant);
  font-size: 14px;
}
@media (max-width: 600px) {
  .brand-tagline { display: none; }
}

/* ---------- container ---------- */

.container {
  max-width: 1080px;
  margin: 0 auto;
  padding: 32px 24px 56px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.hidden { display: none !important; }
.muted { color: var(--md-on-surface-variant); }
.small { font-size: 14px; }

/* ---------- typography ---------- */

.display {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: clamp(32px, 5vw, 48px);
  line-height: 1.1;
  letter-spacing: -0.01em;
  margin: 0 0 12px;
  color: var(--md-on-surface);
}
.title-lg {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 22px;
  line-height: 1.27;
  letter-spacing: 0;
  margin: 0;
}
h1, h2, h3 { color: var(--md-on-surface); }

/* ---------- hero ---------- */

.hero {
  padding: 48px 32px;
  text-align: center;
  background:
    radial-gradient(ellipse 70% 60% at 50% 0%, var(--md-primary-container) 0%, transparent 60%),
    var(--md-surface-container-lowest);
  border-radius: var(--md-radius-xl);
  border: 1px solid var(--md-outline-variant);
}
.hero .lede {
  font-size: 18px;
  line-height: 1.5;
  color: var(--md-on-surface-variant);
  max-width: 56ch;
  margin: 0 auto 28px;
}

/* ---------- card / leaf ---------- */

.card {
  background: var(--md-surface-container-lowest);
  border-radius: var(--md-radius-lg);
  padding: 24px;
  border: 1px solid var(--md-outline-variant);
}

.card-head {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 20px;
}
.card-icon {
  color: var(--md-primary);
  font-size: 24px !important;
}

/* ---------- buttons ---------- */

.btn {
  appearance: none;
  font-family: var(--font-body);
  font-weight: 500;
  font-size: 14px;
  letter-spacing: 0.01em;
  height: 40px;
  padding: 0 20px;
  border-radius: var(--md-radius-pill);
  border: none;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  transition:
    background-color 0.15s ease,
    box-shadow 0.15s ease,
    color 0.15s ease;
  position: relative;
  overflow: hidden;
  user-select: none;
  white-space: nowrap;
}
.btn .material-symbols-outlined { font-size: 18px; }
.btn:focus-visible {
  outline: 2px solid var(--md-primary);
  outline-offset: 2px;
}
/* tonal default (used as the generic .btn when no variant given) */
.btn {
  background: var(--md-secondary-container);
  color: var(--md-on-secondary-container);
}
.btn:hover {
  background: color-mix(in srgb, var(--md-secondary-container) 90%, var(--md-on-secondary-container) 10%);
  box-shadow: var(--md-elev-1);
}
.btn:active {
  background: color-mix(in srgb, var(--md-secondary-container) 80%, var(--md-on-secondary-container) 20%);
}

.btn-filled {
  background: var(--md-primary);
  color: var(--md-on-primary);
}
.btn-filled:hover {
  background: color-mix(in srgb, var(--md-primary) 92%, #000 8%);
  box-shadow: var(--md-elev-1);
}
.btn-filled:active {
  background: color-mix(in srgb, var(--md-primary) 84%, #000 16%);
}

.btn-tonal {
  background: var(--md-secondary-container);
  color: var(--md-on-secondary-container);
}

.btn-text {
  background: transparent;
  color: var(--md-primary);
  padding: 0 12px;
}
.btn-text:hover {
  background: color-mix(in srgb, var(--md-primary) 8%, transparent);
  box-shadow: none;
}
.btn-text:active {
  background: color-mix(in srgb, var(--md-primary) 14%, transparent);
}

.btn-large {
  height: 56px;
  padding: 0 28px;
  font-size: 16px;
}
.btn-large .material-symbols-outlined { font-size: 22px; }

/* ---------- form rows / fields / inputs ---------- */

.row {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  align-items: flex-end;
}
.row + .row { margin-top: 16px; }
.field {
  display: flex;
  flex-direction: column;
  gap: 6px;
  min-width: 160px;
}
.field.grow { flex: 1 1 240px; }
.field > span {
  font-family: var(--font-body);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.04em;
  color: var(--md-on-surface-variant);
}

input[type="text"],
input[type="date"],
select {
  font: inherit;
  font-family: var(--font-body);
  font-size: 16px;
  color: var(--md-on-surface);
  background: var(--md-surface-container-low);
  border: 1px solid var(--md-outline);
  border-radius: var(--md-radius-sm);
  padding: 0 16px;
  height: 48px;
  outline: none;
  transition: border-color 0.15s, box-shadow 0.15s, background 0.15s;
}
input[type="text"]::placeholder { color: var(--md-on-surface-variant); }
input[type="text"]:focus,
input[type="date"]:focus,
select:focus {
  border-color: var(--md-primary);
  box-shadow: inset 0 0 0 1px var(--md-primary);
  background: var(--md-surface-container-lowest);
}
input[readonly] {
  color: var(--md-on-surface-variant);
  background: var(--md-surface-container);
}
select {
  appearance: none;
  background-image:
    linear-gradient(45deg, transparent 50%, var(--md-on-surface-variant) 50%),
    linear-gradient(-45deg, transparent 50%, var(--md-on-surface-variant) 50%);
  background-position:
    calc(100% - 16px) calc(50% + 1px),
    calc(100% - 11px) calc(50% + 1px);
  background-size: 5px 5px, 5px 5px;
  background-repeat: no-repeat;
  padding-right: 40px;
  cursor: pointer;
}

.share-row {
  display: flex;
  gap: 8px;
  align-items: center;
}
.share-row input {
  flex: 1 1 auto;
  font-family: var(--font-mono);
  font-size: 14px;
}

/* ---------- prefs row, M3 switch, holidays ---------- */

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

.toggle {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  cursor: pointer;
  user-select: none;
  padding: 8px 0;
  height: 48px;
}
.toggle input {
  appearance: none;
  width: 52px;
  height: 32px;
  background: var(--md-surface-container-highest);
  border: 2px solid var(--md-outline);
  border-radius: var(--md-radius-pill);
  position: relative;
  cursor: pointer;
  margin: 0;
  flex-shrink: 0;
  transition: background-color 0.2s, border-color 0.2s;
}
.toggle input::before {
  content: "";
  position: absolute;
  top: 50%;
  left: 6px;
  transform: translateY(-50%);
  width: 16px;
  height: 16px;
  background: var(--md-outline);
  border-radius: 50%;
  transition: all 0.22s cubic-bezier(0.4, 0, 0.2, 1);
}
.toggle input:checked {
  background: var(--md-primary);
  border-color: var(--md-primary);
}
.toggle input:checked::before {
  background: var(--md-on-primary);
  width: 24px;
  height: 24px;
  left: 22px;
}
.toggle input:focus-visible {
  outline: 2px solid var(--md-primary);
  outline-offset: 3px;
}
.toggle-label {
  font-size: 14px;
  color: var(--md-on-surface);
}

.holiday-row {
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: 8px;
  align-items: end;
}
@media (max-width: 600px) {
  .holiday-row { grid-template-columns: 1fr; }
}
.holiday-chips {
  margin-top: 12px;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  min-height: 32px;
}
.chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  height: 32px;
  padding: 0 4px 0 12px;
  border: 1px solid var(--md-outline);
  border-radius: var(--md-radius-sm);
  background: transparent;
  color: var(--md-on-surface);
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0.01em;
}
.chip-x {
  appearance: none;
  border: none;
  background: transparent;
  color: var(--md-on-surface-variant);
  width: 24px;
  height: 24px;
  border-radius: 50%;
  font-size: 16px;
  line-height: 1;
  cursor: pointer;
  display: grid;
  place-items: center;
  transition: background 0.15s;
}
.chip-x:hover {
  background: color-mix(in srgb, var(--md-on-surface) 8%, transparent);
}

/* ---------- roster / participants ---------- */

.add-form {
  display: grid;
  grid-template-columns: 1fr 1.5fr auto;
  gap: 12px;
  align-items: end;
}
@media (max-width: 600px) {
  .add-form { grid-template-columns: 1fr; }
}
.status {
  margin-top: 12px;
  min-height: 1.2em;
  font-size: 14px;
  color: var(--md-on-surface-variant);
}
.status.error { color: var(--md-error); }

.participants {
  margin-top: 16px;
  display: flex;
  flex-direction: column;
}
.participant {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 8px 12px 16px;
  border-radius: var(--md-radius-md);
  transition: background 0.15s;
}
.participant:hover {
  background: var(--md-surface-container-low);
}
.participant + .participant {
  margin-top: 4px;
}
.participant .name {
  font-weight: 500;
  color: var(--md-on-surface);
}
.participant .loc {
  color: var(--md-on-surface-variant);
  font-size: 14px;
}
.participant .spacer { flex: 1; }
.participant .tz {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--md-on-surface-variant);
  background: var(--md-surface-container);
  padding: 4px 10px;
  border-radius: var(--md-radius-sm);
  border: none;
  white-space: nowrap;
}
.participant .remove {
  appearance: none;
  border: none;
  background: transparent;
  color: var(--md-on-surface-variant);
  cursor: pointer;
  font-size: 18px;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  transition: background 0.15s, color 0.15s;
}
.participant .remove:hover {
  background: color-mix(in srgb, var(--md-error) 12%, transparent);
  color: var(--md-error);
}

/* ---------- best time / result ---------- */

.result {
  background: var(--md-surface-container-low);
  border-color: transparent;
}

.best-banner {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 20px;
  background: var(--md-primary-container);
  color: var(--md-on-primary-container);
  border-radius: var(--md-radius-lg);
  margin-bottom: 20px;
}
.best-emoji {
  width: 48px;
  height: 48px;
  flex-shrink: 0;
  background: var(--md-on-primary-container);
  color: var(--md-primary-container);
  border-radius: 50%;
  display: grid;
  place-items: center;
  font-size: 24px !important;
}
.best-text { flex: 1; min-width: 0; }
.best-label {
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  opacity: 0.85;
}
.best-time {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: clamp(22px, 3.2vw, 28px);
  line-height: 1.2;
  margin-top: 2px;
  letter-spacing: 0;
}
.best-time-sub {
  font-family: var(--font-mono);
  font-size: 13px;
  margin-top: 4px;
  opacity: 0.8;
  letter-spacing: 0.02em;
}
.best-time-sub:empty { display: none; }

.ai-summary {
  background: var(--md-surface-container);
  border-radius: var(--md-radius-md);
  padding: 16px 20px;
  margin-bottom: 20px;
  font-size: 15px;
  line-height: 1.55;
  color: var(--md-on-surface);
  border-left: 4px solid var(--md-tertiary);
}
.ai-summary:empty { display: none; }
.ai-summary.loading {
  color: var(--md-on-surface-variant);
  font-style: italic;
}

/* ---------- top slots ---------- */

.top-slots { margin-bottom: 20px; }
.top-slots:empty { display: none; }
.top-slots-label {
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.04em;
  color: var(--md-on-surface-variant);
  margin-bottom: 10px;
  text-transform: uppercase;
}
.top-slots-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.alt-slot {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 2px;
  background: var(--md-surface-container-lowest);
  border: 1px solid var(--md-outline-variant);
  padding: 10px 14px;
  border-radius: var(--md-radius-md);
  cursor: pointer;
  font: inherit;
  color: var(--md-on-surface);
  transition: background 0.15s, border-color 0.15s, box-shadow 0.15s;
  min-width: 100px;
}
.alt-slot:hover {
  background: var(--md-surface-container);
  border-color: var(--md-outline);
}
.alt-best {
  background: var(--md-tertiary-container);
  color: var(--md-on-tertiary-container);
  border-color: transparent;
}
.alt-best:hover { background: color-mix(in srgb, var(--md-tertiary-container) 88%, var(--md-on-tertiary-container) 12%); }
.alt-active {
  outline: 2px solid var(--md-primary);
  outline-offset: 2px;
}
.alt-time {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 16px;
  letter-spacing: 0;
}
.alt-meta {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--md-on-surface-variant);
  letter-spacing: 0.04em;
  text-transform: uppercase;
}
.alt-best .alt-meta { color: inherit; opacity: 0.78; }

/* ---------- per-person grid ---------- */

.best-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(190px, 1fr));
  gap: 8px;
  margin-bottom: 20px;
}
.best-cell {
  background: var(--md-surface-container-lowest);
  border: 1px solid var(--md-outline-variant);
  padding: 12px 14px;
  border-radius: var(--md-radius-md);
  display: flex;
  flex-direction: column;
  gap: 2px;
}
.best-cell.bad     { border-color: var(--md-error); background: var(--md-error-container); color: var(--md-on-error-container); }
.best-cell.weekend { border-color: transparent; background: #f3e5f5; color: #4a148c; }
.best-cell.holiday { border-color: transparent; background: #fce4ec; color: #880e4f; }

.best-cell .pname {
  font-weight: 500;
  font-size: 14px;
}
.best-cell .ptime {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 18px;
  line-height: 1.2;
  margin-top: 2px;
}
.best-cell .ptag {
  font-family: var(--font-mono);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-top: 6px;
  opacity: 0.78;
}

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

/* ---------- heatmap ---------- */

.heatmap {
  margin-top: 12px;
  display: flex;
  flex-direction: column;
  gap: 4px;
  overflow-x: auto;
  padding-bottom: 8px;
}
.heat-row {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 760px;
}
.heat-row .label {
  width: 140px;
  flex-shrink: 0;
  font-size: 14px;
  font-weight: 500;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  color: var(--md-on-surface);
}
.heat-row.header .label {
  font-family: var(--font-mono);
  font-weight: 500;
  color: var(--md-on-surface-variant);
  font-size: 11px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}
.cells {
  display: grid;
  grid-template-columns: repeat(48, 1fr);
  gap: 2px;
  flex: 1 1 auto;
}
.cell {
  height: 22px;
  border-radius: 3px;
  cursor: pointer;
  transition: transform 0.08s ease, filter 0.12s;
  border: none;
  padding: 0;
  margin: 0;
  appearance: none;
  font: inherit;
  color: inherit;
  background: var(--md-surface-container-high);
}
.cell:focus-visible {
  outline: 2px solid var(--md-primary);
  outline-offset: 2px;
  z-index: 2;
  position: relative;
}
.cell:hover { transform: scaleY(1.4); filter: brightness(1.06); }

.cell.green   { background: var(--hue-green); }
.cell.stretch { background: var(--hue-stretch); }
.cell.lunch   { background: var(--hue-lunch); }
.cell.red     { background: var(--hue-red); }
.cell.weekend { background: var(--hue-weekend); }
.cell.holiday { background: var(--hue-holiday); }

.cell.best {
  outline: 2px solid var(--md-on-surface);
  outline-offset: 1px;
  z-index: 1;
}

.heat-row.header .cell {
  background: transparent;
  height: 16px;
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--md-on-surface-variant);
  text-align: center;
  cursor: default;
  pointer-events: none;
  letter-spacing: 0.02em;
}
.heat-row.header .cell:hover { transform: none; filter: none; }

/* ---------- legend ---------- */

.legend {
  margin-top: 16px;
  display: flex;
  gap: 12px 20px;
  flex-wrap: wrap;
  font-size: 13px;
  color: var(--md-on-surface-variant);
  align-items: center;
}
.dot {
  display: inline-block;
  width: 14px;
  height: 14px;
  border-radius: 4px;
  margin-right: 6px;
  vertical-align: -3px;
}
.dot-green   { background: var(--hue-green); }
.dot-stretch { background: var(--hue-stretch); }
.dot-lunch   { background: var(--hue-lunch); }
.dot-red     { background: var(--hue-red); }
.dot-weekend { background: var(--hue-weekend); }
.dot-holiday { background: var(--hue-holiday); }

/* ---------- footer ---------- */

.footer {
  text-align: center;
  padding: 32px 16px 48px;
  font-size: 13px;
  color: var(--md-on-surface-variant);
}

/* ---------- entrance choreography ---------- */

@media (prefers-reduced-motion: no-preference) {
  .hero, .leaf {
    animation: rise 0.32s cubic-bezier(0.2, 0, 0, 1) both;
  }
  .hero { animation-delay: 0.04s; }
  #groupSection .leaf:nth-child(1) { animation-delay: 0.06s; }
  #groupSection .leaf:nth-child(2) { animation-delay: 0.10s; }
  #groupSection .leaf:nth-child(3) { animation-delay: 0.14s; }
  #groupSection .leaf:nth-child(4) { animation-delay: 0.18s; }
}
@keyframes rise {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: translateY(0); }
}

.load-error { margin-top: 16px; }