@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap');

:root {
  --bg: #f9fafb;
  --card: #ffffff;
  --border: #e5e7eb;
  --text: #111827;
  --text-secondary: #6b7280;
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --success: #16a34a;
  --warning: #ea580c;
  --danger: #dc2626;
  --input-bg: #f3f4f6;
  --radius: 10px;
  --shadow: 0 1px 3px rgba(0,0,0,0.08);
}

[data-theme="dark"] {
  --bg: #111827;
  --card: #1f2937;
  --border: #374151;
  --text: #f9fafb;
  --text-secondary: #9ca3af;
  --primary: #3b82f6;
  --primary-hover: #2563eb;
  --input-bg: #111827;
  --shadow: 0 1px 3px rgba(0,0,0,0.3);
}

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

body {
  font-family: 'Inter', system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  line-height: 1.5;
}

.app {
  max-width: 640px;
  margin: 0 auto;
  padding: 20px 16px 40px;
}

/* Header */
header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
}

header h1 {
  font-size: 1.3rem;
  font-weight: 700;
}

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

.icon-btn {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 8px;
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 1rem;
  color: var(--text);
  transition: background 0.15s;
}

.icon-btn:hover {
  background: var(--input-bg);
}

/* Date Bar */
.date-bar {
  display: flex;
  align-items: center;
  gap: 12px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 10px 14px;
  margin-bottom: 16px;
  box-shadow: var(--shadow);
}

.date-left {
  display: flex;
  flex-direction: column;
  gap: 1px;
}

.date-bar label {
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.date-hint {
  font-size: 0.68rem;
  color: var(--text-secondary);
  opacity: 0.7;
}

.date-bar input {
  border: none;
  background: none;
  font-family: inherit;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text);
  outline: none;
  cursor: pointer;
}

/* Tabs */
.tabs {
  display: flex;
  gap: 4px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 4px;
  margin-bottom: 20px;
  box-shadow: var(--shadow);
}

.tab {
  flex: 1;
  padding: 8px;
  border: none;
  background: none;
  font-family: inherit;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
  border-radius: 7px;
  cursor: pointer;
  transition: all 0.15s;
}

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

.tab:not(.active):hover {
  color: var(--text);
}

/* Tab Panels */
.tab-panel {
  display: none;
}

.tab-panel.active {
  display: block;
}

/* Summary Row */
.summary-row {
  display: flex;
  gap: 8px;
  margin-bottom: 16px;
}

.summary-stat {
  flex: 1;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 12px;
  text-align: center;
  box-shadow: var(--shadow);
}

.stat-label {
  display: block;
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-secondary);
  margin-bottom: 2px;
}

.stat-value {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text);
}

.summary-stat.green .stat-value {
  color: var(--success);
}

.summary-stat.amber .stat-value {
  color: var(--warning);
}

.summary-stat.red .stat-value {
  color: var(--danger);
}

/* Toolbar */
.toolbar {
  display: flex;
  gap: 8px;
  margin-bottom: 16px;
}

.toolbar input {
  flex: 1;
  padding: 9px 12px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-family: inherit;
  font-size: 0.85rem;
  color: var(--text);
  outline: none;
  transition: border-color 0.15s;
}

.toolbar input:focus {
  border-color: var(--primary);
}

/* Buttons */
.btn-primary {
  background: var(--primary);
  color: #fff;
  border: none;
  border-radius: var(--radius);
  padding: 9px 16px;
  font-family: inherit;
  font-size: 0.82rem;
  font-weight: 600;
  cursor: pointer;
  white-space: nowrap;
  transition: background 0.15s;
}

.btn-primary:hover {
  background: var(--primary-hover);
}

.btn-secondary {
  background: var(--card);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 9px 16px;
  font-family: inherit;
  font-size: 0.82rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s;
}

.btn-secondary:hover {
  background: var(--input-bg);
}

.btn-danger {
  background: #fef2f2;
  color: var(--danger);
  border: 1px solid #fecaca;
  border-radius: var(--radius);
  padding: 9px 16px;
  font-family: inherit;
  font-size: 0.82rem;
  font-weight: 600;
  cursor: pointer;
  width: 100%;
  transition: background 0.15s;
}

.btn-danger:hover {
  background: #fee2e2;
}

[data-theme="dark"] .btn-danger {
  background: rgba(220,38,38,0.15);
  border-color: rgba(220,38,38,0.3);
}

[data-theme="dark"] .btn-danger:hover {
  background: rgba(220,38,38,0.25);
}

/* Subject Cards */
.subject-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px;
  margin-bottom: 10px;
  box-shadow: var(--shadow);
}

.subject-top {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 10px;
}

.subject-info h4 {
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 2px;
}

.subject-code {
  font-size: 0.75rem;
  color: var(--text-secondary);
}

.subject-percent {
  font-size: 1.2rem;
  font-weight: 700;
  text-align: right;
}

.subject-badge {
  display: inline-block;
  font-size: 0.65rem;
  font-weight: 600;
  padding: 2px 6px;
  border-radius: 4px;
  margin-top: 2px;
  text-transform: uppercase;
}

.badge-safe {
  background: #dcfce7;
  color: var(--success);
}

.badge-warning {
  background: #fff7ed;
  color: var(--warning);
}

.badge-danger {
  background: #fef2f2;
  color: var(--danger);
}

[data-theme="dark"] .badge-safe {
  background: rgba(22,163,74,0.15);
}

[data-theme="dark"] .badge-warning {
  background: rgba(234,88,12,0.15);
}

[data-theme="dark"] .badge-danger {
  background: rgba(220,38,38,0.15);
}

.progress-track {
  width: 100%;
  height: 6px;
  background: var(--input-bg);
  border-radius: 3px;
  margin-bottom: 10px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  border-radius: 3px;
  transition: width 0.3s ease;
}

.subject-meta {
  display: flex;
  justify-content: space-between;
  font-size: 0.78rem;
  color: var(--text-secondary);
  margin-bottom: 10px;
}

.subject-actions {
  display: flex;
  gap: 6px;
}

.subject-actions button {
  flex: 1;
  padding: 7px 0;
  border-radius: 6px;
  font-family: inherit;
  font-size: 0.75rem;
  font-weight: 600;
  cursor: pointer;
  border: 1px solid transparent;
  transition: all 0.15s;
}

.action-present {
  background: #dcfce7;
  color: var(--success);
  border-color: #bbf7d0;
}

.action-present:hover {
  background: #bbf7d0;
}

.action-absent {
  background: #fef2f2;
  color: var(--danger);
  border-color: #fecaca;
}

.action-absent:hover {
  background: #fecaca;
}

.action-history {
  background: var(--input-bg);
  color: var(--text-secondary);
  border-color: var(--border);
}

.action-history:hover {
  color: var(--text);
}

.action-edit {
  background: var(--input-bg);
  color: var(--text-secondary);
  border-color: var(--border);
}

.action-edit:hover {
  color: var(--text);
}

.action-delete {
  background: var(--input-bg);
  color: var(--text-secondary);
  border-color: var(--border);
  max-width: 36px;
  flex: 0 0 36px;
}

.action-delete:hover {
  color: var(--danger);
}

/* Empty State */
.empty-state {
  text-align: center;
  padding: 48px 20px;
  background: var(--card);
  border: 1px dashed var(--border);
  border-radius: var(--radius);
}

.empty-state p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: 16px;
}

/* Simulator */
.sim-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  box-shadow: var(--shadow);
}

.sim-inputs {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 10px;
  margin-bottom: 20px;
}

.input-group {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.input-group label {
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

.input-group input {
  padding: 9px 10px;
  background: var(--input-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  font-family: inherit;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text);
  outline: none;
  width: 100%;
  transition: border-color 0.15s;
}

.input-group input:focus {
  border-color: var(--primary);
}

.sim-result {
  text-align: center;
  padding: 20px;
  background: var(--input-bg);
  border-radius: var(--radius);
  margin-bottom: 14px;
}

.sim-percent {
  font-size: 2.2rem;
  font-weight: 700;
  margin-bottom: 4px;
}

.sim-status {
  font-size: 0.85rem;
  font-weight: 500;
}

.sim-status.safe {
  color: var(--success);
}

.sim-status.warning {
  color: var(--warning);
}

.sim-status.danger {
  color: var(--danger);
}

.sim-deltas {
  display: flex;
  justify-content: center;
  gap: 20px;
  font-size: 0.78rem;
  color: var(--text-secondary);
  margin-bottom: 16px;
}

.sim-controls {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 8px;
}

.sim-btn {
  padding: 9px;
  border-radius: 8px;
  font-family: inherit;
  font-size: 0.82rem;
  font-weight: 600;
  cursor: pointer;
  border: 1px solid var(--border);
  transition: all 0.15s;
}

.sim-btn.present {
  background: #dcfce7;
  color: var(--success);
  border-color: #bbf7d0;
}

.sim-btn.present:hover {
  background: #bbf7d0;
}

.sim-btn.absent {
  background: #fef2f2;
  color: var(--danger);
  border-color: #fecaca;
}

.sim-btn.absent:hover {
  background: #fecaca;
}

.sim-btn.reset {
  background: var(--input-bg);
  color: var(--text-secondary);
}

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

.sim-delta-label {
  text-align: center;
  font-size: 0.78rem;
  color: var(--text-secondary);
  margin-top: 10px;
  min-height: 20px;
}

/* Modals */
.modal {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.4);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px;
  z-index: 100;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.15s;
}

.modal.open {
  opacity: 1;
  pointer-events: auto;
}

.modal-box {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  width: 100%;
  max-width: 420px;
  box-shadow: 0 20px 40px rgba(0,0,0,0.15);
}

.modal-wide {
  max-width: 520px;
}

.modal-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border);
}

.modal-head h3 {
  font-size: 1rem;
  font-weight: 700;
}

.modal-sub {
  font-size: 0.78rem;
  color: var(--text-secondary);
  margin-top: 2px;
}

.close-btn {
  background: none;
  border: none;
  font-size: 1.3rem;
  color: var(--text-secondary);
  cursor: pointer;
  line-height: 1;
}

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

.modal-box form {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.input-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

.modal-actions {
  display: flex;
  justify-content: flex-end;
  gap: 8px;
  margin-top: 8px;
}

/* History */
.history-list {
  max-height: 340px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.history-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: var(--input-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 12px;
  gap: 8px;
}

.history-left {
  display: flex;
  align-items: center;
  gap: 10px;
  flex: 1;
  min-width: 0;
}

.history-idx {
  font-size: 0.7rem;
  font-weight: 600;
  color: var(--text-secondary);
  flex-shrink: 0;
}

.history-details {
  min-width: 0;
}

.history-date {
  font-size: 0.82rem;
  font-weight: 600;
  display: block;
}

.history-note {
  font-size: 0.72rem;
  color: var(--text-secondary);
  display: block;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.history-tag {
  font-size: 0.68rem;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: 4px;
  flex-shrink: 0;
}

.tag-present {
  background: #dcfce7;
  color: var(--success);
}

.tag-absent {
  background: #fef2f2;
  color: var(--danger);
}

.history-del {
  background: none;
  border: none;
  color: var(--text-secondary);
  font-size: 1rem;
  cursor: pointer;
  padding: 2px 4px;
  flex-shrink: 0;
}

.history-del:hover {
  color: var(--danger);
}

/* Data Modal */
.data-actions {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.data-actions .btn-secondary {
  width: 100%;
  justify-content: center;
}

.file-label {
  text-align: center;
  cursor: pointer;
}

.data-actions hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 4px 0;
}

/* Toast */
.toast-container {
  position: fixed;
  bottom: 20px;
  right: 20px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  z-index: 200;
  pointer-events: none;
}

.toast {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 16px;
  font-size: 0.82rem;
  font-weight: 500;
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
  pointer-events: auto;
  animation: slideIn 0.2s ease forwards;
}

@keyframes slideIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Responsive */
@media (max-width: 480px) {
  .sim-inputs {
    grid-template-columns: 1fr;
  }

  .sim-controls {
    grid-template-columns: 1fr 1fr 1fr;
  }

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