:root {
  --color-bg: #faf7f0;
  --color-surface: #ffffff;
  --color-primary: #2f5aa8;
  --color-primary-dark: #1d3f7a;
  --color-accent: #5b86c9;
  --color-amber: #f0a93a;
  --color-amber-dark: #d68a1a;
  --color-green: #2fb463;
  --color-text: #1b2635;
  --color-text-muted: #74808f;
  --color-border: #ece6d8;
  --color-danger: #c0392b;
  --safe-bottom: env(safe-area-inset-bottom, 0px);
}

* {
  box-sizing: border-box;
}

[hidden] {
  display: none !important;
}

html, body {
  height: 100%;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--color-bg);
  color: var(--color-text);
  -webkit-tap-highlight-color: transparent;
}

/* ---------- App header ---------- */

.app-header {
  display: flex;
  align-items: center;
  gap: 10px;
  max-width: 480px;
  margin: 0 auto;
  padding: 16px 20px 4px;
}

.app-header-icon {
  width: 36px;
  height: 36px;
  border-radius: 9px;
  display: block;
}

.app-header-title {
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--color-text);
}

main {
  max-width: 480px;
  margin: 0 auto;
  padding: 8px 20px calc(96px + var(--safe-bottom));
  min-height: 100vh;
}

.view {
  display: none;
}

.view.active {
  display: block;
  animation: fade-in .15s ease-out;
}

@keyframes fade-in {
  from { opacity: 0; }
  to { opacity: 1; }
}

/* ---------- Home ---------- */

.today-card {
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  border-radius: 22px;
  padding: 22px 22px 24px;
  margin: 16px 0 12px;
  color: #fff;
  box-shadow: 0 10px 24px rgba(29, 63, 122, 0.25);
}

.today-card-label {
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: rgba(255, 255, 255, 0.75);
}

.today-card-date {
  font-size: 1.7rem;
  font-weight: 800;
  margin-top: 4px;
}

.today-card-period {
  display: inline-block;
  margin-top: 12px;
  padding: 6px 14px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.18);
  font-size: 0.85rem;
  font-weight: 700;
}

.today-card-question {
  margin: 14px 0 0;
  font-size: 0.92rem;
  color: rgba(255, 255, 255, 0.85);
}

.link-btn {
  border: none;
  background: none;
  color: var(--color-primary);
  font-size: 0.9rem;
  font-weight: 600;
  padding: 8px 6px;
  margin-top: 4px;
  cursor: pointer;
  text-decoration: underline;
  text-underline-offset: 2px;
}

.link-btn.centered {
  display: block;
  margin: 0 auto 8px;
}

.date-picker-panel {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 16px;
  padding: 16px;
  margin-bottom: 20px;
}

.date-picker-panel .field-label {
  margin-top: 0;
}

.period-pills {
  display: flex;
  gap: 8px;
  margin: 14px 0 16px;
}

.period-pill {
  flex: 1;
  border: 1px solid var(--color-border);
  background: var(--color-bg);
  color: var(--color-text);
  padding: 10px 4px;
  border-radius: 10px;
  font-size: 0.88rem;
  font-weight: 600;
  cursor: pointer;
}

.period-pill.active {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: #fff;
}

.date-picker-panel .link-btn {
  display: block;
  margin: 0 auto;
}

.view-hint {
  margin: -10px 0 18px;
  color: var(--color-text-muted);
  font-size: 0.88rem;
}

.log-hint {
  text-align: center;
  color: var(--color-text-muted);
  font-size: 0.85rem;
  font-weight: 600;
  margin: 4px 0 14px;
}

.button-stack {
  display: flex;
  flex-direction: column;
  gap: 14px;
  margin-bottom: 22px;
}

.qty-btn {
  border: none;
  border-radius: 20px;
  padding: 20px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  cursor: pointer;
  text-align: left;
  transition: transform .08s ease, box-shadow .08s ease;
  -webkit-user-select: none;
  user-select: none;
}

.qty-btn:active {
  transform: scale(0.98);
}

.qty-btn-text {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.qty-btn-title {
  font-size: 1.3rem;
  font-weight: 800;
}

.qty-btn-subtitle {
  font-size: 0.85rem;
  font-weight: 600;
  opacity: 0.85;
}

.qty-btn-icon {
  width: 46px;
  height: 46px;
  min-width: 46px;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.qty-btn-icon svg {
  width: 22px;
  height: 22px;
}

.qty-btn--full {
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  color: #fff;
  box-shadow: 0 8px 18px rgba(29, 63, 122, 0.28);
}

.qty-btn--full .qty-btn-icon {
  background: rgba(255, 255, 255, 0.18);
  color: #fff;
}

.qty-btn--half {
  background: var(--color-surface);
  color: var(--color-text);
  border: 1px solid var(--color-border);
}

.qty-btn--half .qty-btn-subtitle {
  color: var(--color-text-muted);
  opacity: 1;
}

.qty-btn--half .qty-btn-icon {
  background: #eaf1fb;
  color: var(--color-primary);
}

.today-entries {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 14px;
}

.entry-status-row {
  display: flex;
  align-items: center;
  gap: 10px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 14px;
  padding: 12px 14px;
  font-size: 0.92rem;
}

.entry-status-dot {
  width: 8px;
  height: 8px;
  min-width: 8px;
  border-radius: 50%;
  background: var(--color-green);
}

.entry-status-label {
  flex: 1;
  font-weight: 600;
  color: var(--color-text);
}

.entry-status-value {
  font-weight: 700;
  color: var(--color-primary-dark);
}

.month-summary-card {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  width: 100%;
  border: none;
  cursor: pointer;
  text-align: left;
  background: linear-gradient(135deg, var(--color-amber), var(--color-amber-dark));
  border-radius: 18px;
  padding: 16px 18px;
  color: #3a2a09;
  box-shadow: 0 8px 18px rgba(214, 138, 26, 0.28);
}

.month-summary-text {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.month-summary-title {
  font-weight: 800;
  font-size: 1rem;
}

.month-summary-subtitle {
  font-size: 0.82rem;
  font-weight: 600;
  opacity: 0.8;
}

.month-summary-chevron {
  font-size: 1.4rem;
  font-weight: 700;
  line-height: 1;
  width: 34px;
  height: 34px;
  min-width: 34px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.35);
  display: flex;
  align-items: center;
  justify-content: center;
}

/* ---------- Shared view bits ---------- */

.view-title {
  font-size: 1.4rem;
  margin: 12px 0 20px;
  color: var(--color-primary-dark);
}

/* ---------- History ---------- */

.history-list {
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.history-group {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 16px;
  padding: 14px 16px;
}

.history-group-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 10px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--color-border);
}

.history-group-date {
  font-weight: 700;
  font-size: 1.05rem;
}

.history-group-total {
  font-size: 0.9rem;
  color: var(--color-text-muted);
}

.history-entry {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 8px 0;
}

.history-entry + .history-entry {
  border-top: 1px dashed var(--color-border);
}

.history-entry-info {
  display: flex;
  gap: 10px;
  align-items: baseline;
  flex: 1;
  cursor: pointer;
  padding: 4px 0;
}

.history-entry-period {
  font-weight: 600;
}

.history-entry-liters {
  color: var(--color-primary-dark);
  font-weight: 700;
}

.delete-btn {
  border: none;
  background: none;
  color: var(--color-danger);
  font-size: 1.2rem;
  padding: 6px 10px;
  cursor: pointer;
  line-height: 1;
}

.empty-state {
  text-align: center;
  color: var(--color-text-muted);
  padding: 40px 10px;
  font-size: 0.95rem;
}

/* ---------- Bill ---------- */

.field-label {
  display: block;
  margin: 18px 0 6px;
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--color-text-muted);
}

.field-input {
  width: 100%;
  padding: 14px 16px;
  font-size: 1.1rem;
  border-radius: 12px;
  border: 1px solid var(--color-border);
  background: var(--color-surface);
  color: var(--color-text);
}

.field-input:focus {
  outline: 2px solid var(--color-primary);
}

.primary-btn {
  width: 100%;
  margin-top: 24px;
  padding: 16px;
  border: none;
  border-radius: 14px;
  background: var(--color-primary);
  color: #fff;
  font-size: 1.05rem;
  font-weight: 700;
  cursor: pointer;
}

.primary-btn:active {
  background: var(--color-primary-dark);
}

.bill-result {
  margin-top: 24px;
}

.bill-result:empty {
  margin-top: 0;
}

.bill-summary {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 16px;
  padding: 18px;
}

.bill-row {
  display: flex;
  justify-content: space-between;
  padding: 8px 0;
  font-size: 1rem;
}

.bill-row + .bill-row {
  border-top: 1px solid var(--color-border);
}

.bill-row.total {
  font-weight: 800;
  font-size: 1.2rem;
  color: var(--color-primary-dark);
}

/* ---------- Tab bar ---------- */

.tabbar {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  display: flex;
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: 8px 8px calc(8px + var(--safe-bottom));
  z-index: 10;
}

.tab-btn {
  flex: 1;
  border: none;
  background: none;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  padding: 6px 4px;
  font-size: 0.78rem;
  color: var(--color-text-muted);
  cursor: pointer;
  border-radius: 10px;
}

.tab-btn.active {
  color: var(--color-primary-dark);
  font-weight: 700;
}

.tab-icon {
  font-size: 1.3rem;
}

/* ---------- Toast ---------- */

.toast {
  position: fixed;
  left: 50%;
  bottom: calc(90px + var(--safe-bottom));
  transform: translate(-50%, 12px);
  background: var(--color-text);
  color: #fff;
  padding: 12px 20px;
  border-radius: 999px;
  font-size: 0.95rem;
  font-weight: 600;
  opacity: 0;
  pointer-events: none;
  transition: opacity .2s ease, transform .2s ease;
  z-index: 20;
  white-space: nowrap;
}

.toast.show {
  opacity: 1;
  transform: translate(-50%, 0);
}

/* ---------- Add to Home Screen prompt ---------- */

.install-overlay {
  position: fixed;
  inset: 0;
  background: rgba(27, 38, 53, 0.45);
  display: flex;
  align-items: flex-end;
  justify-content: center;
  z-index: 30;
  padding: 16px;
}

.install-overlay[hidden] {
  display: none;
}

.install-sheet {
  width: 100%;
  max-width: 420px;
  background: var(--color-surface);
  border-radius: 20px;
  padding: 26px 22px calc(20px + var(--safe-bottom));
  text-align: center;
  box-shadow: 0 -8px 28px rgba(27, 38, 53, 0.3);
  animation: sheet-up .18s ease-out;
}

@keyframes sheet-up {
  from { transform: translateY(16px); opacity: 0; }
  to { transform: translateY(0); opacity: 1; }
}

.install-sheet-icon img {
  width: 44px;
  height: 44px;
  border-radius: 11px;
  display: block;
  margin: 0 auto 14px;
}

.install-sheet-title {
  margin: 0 0 8px;
  font-size: 1.1rem;
  color: var(--color-text);
}

.install-sheet-body {
  margin: 0 0 20px;
  color: var(--color-text-muted);
  font-size: 0.92rem;
  line-height: 1.4;
}

.install-sheet-cta {
  width: 100%;
  border: none;
  border-radius: 14px;
  padding: 15px;
  background: var(--color-primary);
  color: #fff;
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
}

.install-sheet-cta:active {
  background: var(--color-primary-dark);
}

.install-sheet-dismiss {
  width: 100%;
  border: none;
  background: none;
  padding: 14px;
  margin-top: 4px;
  color: var(--color-text-muted);
  font-size: 0.92rem;
  font-weight: 600;
  cursor: pointer;
}

@media (min-width: 480px) {
  .app-header {
    padding-top: 28px;
  }
}