:root {
  color-scheme: dark;
  font-family: "Segoe UI", system-ui, -apple-system, sans-serif;
  --bg: #0f172a;
  --bg2: #1e293b;
  --card: #111827;
  --accent: #22c55e;
  --accent-warn: #f97316;
  --accent-danger: #ef4444;
  --accent-blue: #3b82f6;
  --text: #e2e8f0;
  --muted: #94a3b8;
}

body.light {
  --bg: #f1f5f9;
  --bg2: #e2e8f0;
  --card: #ffffff;
  --text: #1e293b;
  --muted: #64748b;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: radial-gradient(circle at top, var(--bg2), var(--bg) 60%);
  color: var(--text);
  min-height: 100vh;
  transition: background 0.3s, color 0.3s;
}

.theme-toggle {
  position: fixed;
  top: 16px;
  right: 16px;
  display: flex;
  gap: 8px;
  z-index: 100;
}

.theme-toggle button {
  background: var(--card);
  border: 1px solid var(--muted);
  color: var(--text);
  font-size: 18px;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  cursor: pointer;
  transition: transform 0.2s;
}

.theme-toggle button:hover {
  transform: scale(1.1);
}

.app {
  max-width: 1100px;
  margin: 0 auto;
  padding: 20px 20px 60px;
}

.app__header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
  margin-bottom: 24px;
}

.header-actions {
  display: flex;
  gap: 10px;
  align-items: center;
}

h1 {
  margin: 0 0 4px;
  font-size: 26px;
}

#clockDisplay {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
}

.btn {
  background: linear-gradient(135deg, #22c55e, #16a34a);
  border: none;
  color: #fff;
  font-weight: 700;
  padding: 12px 20px;
  border-radius: 10px;
  cursor: pointer;
  transition: transform 0.15s, box-shadow 0.2s;
}

.btn:hover {
  box-shadow: 0 4px 15px rgba(34, 197, 94, 0.4);
}

.btn:active {
  transform: translateY(1px);
}

.btn-secondary {
  background: var(--card);
  border: 1px solid var(--muted);
  color: var(--text);
}

.btn-danger {
  background: linear-gradient(135deg, #ef4444, #dc2626);
}

select {
  background: var(--card);
  border: 1px solid var(--muted);
  color: var(--text);
  padding: 10px 14px;
  border-radius: 8px;
  font-size: 14px;
  cursor: pointer;
}

/* Water Drop Animation */
.water-drop-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  margin: 30px 0;
}

.water-drop {
  width: 140px;
  height: 180px;
  background: linear-gradient(180deg, #0ea5e9 0%, #0284c7 100%);
  border-radius: 50% 50% 50% 50% / 60% 60% 40% 40%;
  position: relative;
  overflow: hidden;
  box-shadow: 0 10px 40px rgba(14, 165, 233, 0.3), inset 0 -20px 40px rgba(0,0,0,0.2);
  display: flex;
  align-items: center;
  justify-content: center;
}

.water-fill {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  background: linear-gradient(180deg, #22d3ee 0%, #06b6d4 100%);
  transition: height 0.5s ease;
  height: 0%;
}

.drop-value {
  position: relative;
  z-index: 2;
  font-size: 22px;
  font-weight: bold;
  color: #fff;
  text-shadow: 0 2px 4px rgba(0,0,0,0.3);
}

.drop-label {
  margin-top: 10px;
  color: var(--muted);
  font-size: 14px;
}

.water-drop.warning {
  background: linear-gradient(180deg, #f59e0b 0%, #d97706 100%);
}

.water-drop.danger {
  background: linear-gradient(180deg, #ef4444 0%, #dc2626 100%);
  animation: pulse 1s infinite;
}

@keyframes pulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.05); }
}

/* Cards */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 16px;
  margin-bottom: 24px;
}

.card {
  background: var(--card);
  border-radius: 14px;
  padding: 18px;
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.2);
  transition: transform 0.2s, box-shadow 0.2s;
}

.card:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 30px rgba(0, 0, 0, 0.3);
}

.card h2 {
  margin: 0 0 10px;
  font-size: 13px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 1px;
}

.value {
  font-size: 28px;
  display: flex;
  align-items: baseline;
  gap: 6px;
  font-weight: 600;
}

.unit {
  font-size: 13px;
  color: var(--muted);
  font-weight: normal;
}

.status.ok { border-left: 4px solid var(--accent); }
.status.warn { border-left: 4px solid var(--accent-warn); }
.status.danger { border-left: 4px solid var(--accent-danger); }

.sub {
  margin-top: 6px;
  color: var(--muted);
  font-size: 12px;
}

/* Budget Section */
.budget-section {
  background: var(--card);
  border-radius: 14px;
  padding: 20px;
  margin-bottom: 24px;
}

.budget-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
}

.budget-header h3 {
  margin: 0;
  font-size: 16px;
}

#budgetText {
  color: var(--muted);
  font-size: 14px;
}

.progress-bar {
  height: 24px;
  background: var(--bg);
  border-radius: 12px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, #22c55e, #16a34a);
  border-radius: 12px;
  transition: width 0.5s ease, background 0.3s;
  width: 0%;
}

.progress-fill.warning {
  background: linear-gradient(90deg, #f59e0b, #d97706);
}

.progress-fill.danger {
  background: linear-gradient(90deg, #ef4444, #dc2626);
}

#budgetStatus {
  margin-top: 10px;
  font-size: 13px;
  color: var(--accent);
}

#budgetStatus.warning { color: var(--accent-warn); }
#budgetStatus.danger { color: var(--accent-danger); }

/* Chart Sections */
.chart-section, .history-section {
  background: var(--card);
  border-radius: 14px;
  padding: 20px;
  margin-bottom: 24px;
}

.chart-section h3, .history-section h3 {
  margin: 0 0 16px;
  font-size: 16px;
}

.chart-container {
  position: relative;
  height: 220px;
  width: 100%;
}

.chart-container canvas {
  position: absolute;
  top: 0;
  left: 0;
  width: 100% !important;
  height: 100% !important;
}

.history-tabs {
  display: flex;
  gap: 8px;
  margin-bottom: 16px;
}

.tab-btn {
  background: var(--bg);
  border: none;
  color: var(--muted);
  padding: 8px 16px;
  border-radius: 8px;
  cursor: pointer;
  transition: background 0.2s, color 0.2s;
}

.tab-btn.active {
  background: var(--accent);
  color: #fff;
}

/* Session Summary */
.session-summary {
  background: var(--card);
  border-radius: 14px;
  padding: 20px;
  margin-bottom: 24px;
}

.session-summary h3 {
  margin: 0 0 16px;
  font-size: 16px;
}

.summary-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 16px;
}

.summary-item {
  text-align: center;
}

.summary-item .label {
  display: block;
  font-size: 12px;
  color: var(--muted);
  margin-bottom: 4px;
}

.summary-item .val {
  font-size: 20px;
  font-weight: 600;
}

/* Eco Cards */
.eco-cards .card.eco {
  border-top: 3px solid var(--accent);
}

/* Achievements */
.achievements-section {
  background: var(--card);
  border-radius: 14px;
  padding: 20px;
  margin-bottom: 24px;
}

.achievements-section h3 {
  margin: 0 0 16px;
  font-size: 16px;
}

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

.badge {
  width: 60px;
  height: 60px;
  background: var(--bg);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 28px;
  transition: transform 0.2s, box-shadow 0.2s;
  cursor: pointer;
  position: relative;
}

.badge.locked {
  filter: grayscale(1);
  opacity: 0.4;
}

.badge.unlocked {
  filter: none;
  opacity: 1;
  box-shadow: 0 0 20px rgba(34, 197, 94, 0.5);
  animation: badgePop 0.5s ease;
}

@keyframes badgePop {
  0% { transform: scale(0.5); }
  50% { transform: scale(1.2); }
  100% { transform: scale(1); }
}

.badge:hover {
  transform: scale(1.1);
}

/* Leaderboard */
.leaderboard-section {
  background: var(--card);
  border-radius: 14px;
  padding: 20px;
  margin-bottom: 24px;
}

.leaderboard-section h3 {
  margin: 0 0 16px;
  font-size: 16px;
}

.leader-row {
  display: grid;
  grid-template-columns: 50px 1fr 100px 80px;
  gap: 10px;
  padding: 12px;
  border-radius: 8px;
  align-items: center;
}

.leader-row.header {
  background: var(--bg);
  font-size: 12px;
  color: var(--muted);
  text-transform: uppercase;
}

.leader-row:not(.header) {
  background: var(--bg);
  margin-top: 8px;
}

.leader-row:not(.header):nth-child(2) {
  background: linear-gradient(90deg, rgba(255, 215, 0, 0.2), transparent);
  border-left: 3px solid gold;
}

.leader-row:not(.header):nth-child(3) {
  background: linear-gradient(90deg, rgba(192, 192, 192, 0.2), transparent);
  border-left: 3px solid silver;
}

.leader-row:not(.header):nth-child(4) {
  background: linear-gradient(90deg, rgba(205, 127, 50, 0.2), transparent);
  border-left: 3px solid #cd7f32;
}

/* Log Section */
.log {
  background: #0b1120;
  border-radius: 14px;
  padding: 16px;
  border: 1px solid rgba(148, 163, 184, 0.2);
}

.log__header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 10px;
  color: var(--muted);
}

.log__header h3 {
  margin: 0;
  font-size: 14px;
}

pre {
  margin: 0;
  font-size: 12px;
  color: #cbd5f5;
  min-height: 60px;
  white-space: pre-wrap;
  font-family: 'Consolas', monospace;
}

/* Modal */
.modal {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.7);
  z-index: 200;
  align-items: center;
  justify-content: center;
}

.modal.show {
  display: flex;
}

.modal-content {
  background: var(--card);
  border-radius: 16px;
  width: 90%;
  max-width: 480px;
  max-height: 90vh;
  overflow-y: auto;
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px;
  border-bottom: 1px solid var(--bg);
}

.modal-header h2 {
  margin: 0;
  font-size: 20px;
}

.close-btn {
  background: none;
  border: none;
  color: var(--muted);
  font-size: 28px;
  cursor: pointer;
  line-height: 1;
}

.close-btn:hover {
  color: var(--text);
}

.modal-body {
  padding: 20px;
}

.setting-group {
  margin-bottom: 20px;
}

.setting-group label {
  display: block;
  font-size: 14px;
  margin-bottom: 8px;
  color: var(--muted);
}

.setting-group input[type="number"] {
  width: 100%;
  background: var(--bg);
  border: 1px solid var(--muted);
  color: var(--text);
  padding: 12px;
  border-radius: 8px;
  font-size: 16px;
}

.setting-group input[type="checkbox"] {
  width: 18px;
  height: 18px;
  margin-right: 8px;
  vertical-align: middle;
}

.setting-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 24px;
  padding-top: 20px;
  border-top: 1px solid var(--bg);
}

/* Mobile Responsive */
@media (max-width: 600px) {
  .app {
    padding: 16px 12px 40px;
  }

  .app__header {
    flex-direction: column;
    text-align: center;
  }

  h1 {
    font-size: 22px;
  }

  .header-actions {
    flex-wrap: wrap;
    justify-content: center;
  }

  .water-drop {
    width: 120px;
    height: 150px;
  }

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

  .value {
    font-size: 22px;
  }

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

  .leader-row {
    grid-template-columns: 40px 1fr 70px 60px;
    font-size: 13px;
    padding: 10px;
  }

  .badge {
    width: 50px;
    height: 50px;
    font-size: 22px;
  }
}