/* ===== CSS Variables ===== */
:root {
  --primary: #6C63FF;
  --primary-dark: #5a52d5;
  --primary-light: #ede9ff;
  --success: #43D9AD;
  --warning: #FFB347;
  --danger: #FF6B6B;
  --low: #43D9AD;
  --medium: #FFB347;
  --high: #FF6B6B;

  --bg: #F4F6FB;
  --surface: #FFFFFF;
  --surface2: #F0F2F8;
  --border: #E2E6F0;
  --text: #1E1E2E;
  --text-muted: #7B7F9E;
  --shadow: 0 4px 24px rgba(108,99,255,0.10);
  --shadow-sm: 0 2px 8px rgba(108,99,255,0.07);
  --radius: 16px;
  --radius-sm: 10px;
  --transition: 0.22s cubic-bezier(.4,0,.2,1);
}

[data-theme="dark"] {
  --bg: #13131F;
  --surface: #1E1E2E;
  --surface2: #252535;
  --border: #2E2E45;
  --text: #E8E8F5;
  --text-muted: #7B7F9E;
  --primary-light: #2a2660;
  --shadow: 0 4px 24px rgba(0,0,0,0.35);
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.25);
}

/* ===== Reset ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; -webkit-tap-highlight-color: transparent; }
body {
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100dvh;
  transition: background var(--transition), color var(--transition);
  overscroll-behavior: none;
}

/* ===== App Wrapper ===== */
.app-wrapper {
  max-width: 480px;
  margin: 0 auto;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  padding-bottom: env(safe-area-inset-bottom, 16px);
}

/* ===== Header ===== */
.app-header {
  background: linear-gradient(135deg, var(--primary) 0%, #8B5CF6 100%);
  color: #fff;
  padding: 28px 20px 20px;
  border-radius: 0 0 28px 28px;
  box-shadow: 0 8px 32px rgba(108,99,255,0.25);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 18px;
}

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

.header-icon { font-size: 1.5rem; }

.app-header h1 {
  font-size: 1.6rem;
  font-weight: 800;
  letter-spacing: -0.5px;
}

.theme-toggle {
  background: rgba(255,255,255,0.18);
  border: none;
  border-radius: 50%;
  width: 40px;
  height: 40px;
  font-size: 1.2rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background var(--transition), transform var(--transition);
}
.theme-toggle:hover { background: rgba(255,255,255,0.28); transform: rotate(20deg); }

.header-stats {
  display: flex;
  gap: 12px;
  margin-bottom: 16px;
}

.stat-card {
  flex: 1;
  background: rgba(255,255,255,0.15);
  border-radius: var(--radius-sm);
  padding: 10px 8px;
  text-align: center;
  backdrop-filter: blur(4px);
}

.stat-number {
  display: block;
  font-size: 1.5rem;
  font-weight: 800;
  line-height: 1;
}

.stat-label {
  font-size: 0.72rem;
  opacity: 0.85;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.progress-container {
  display: flex;
  align-items: center;
  gap: 10px;
}

.progress-bar {
  flex: 1;
  height: 8px;
  background: rgba(255,255,255,0.25);
  border-radius: 99px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: #fff;
  border-radius: 99px;
  width: 0%;
  transition: width 0.5s cubic-bezier(.4,0,.2,1);
}

.progress-label {
  font-size: 0.75rem;
  opacity: 0.9;
  white-space: nowrap;
  min-width: 80px;
  text-align: right;
}

/* ===== Add Section ===== */
.add-section {
  padding: 18px 16px 0;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.input-group {
  display: flex;
  gap: 8px;
}

.task-input {
  flex: 1;
  padding: 13px 16px;
  border: 2px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--surface);
  color: var(--text);
  font-size: 0.95rem;
  outline: none;
  transition: border-color var(--transition), box-shadow var(--transition);
}
.task-input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(108,99,255,0.15);
}
.task-input::placeholder { color: var(--text-muted); }

.priority-select {
  padding: 10px;
  border: 2px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--surface);
  color: var(--text);
  font-size: 0.85rem;
  outline: none;
  cursor: pointer;
  transition: border-color var(--transition);
  min-width: 110px;
}
.priority-select:focus { border-color: var(--primary); }

.input-row {
  display: flex;
  gap: 8px;
  align-items: center;
}

.date-input {
  flex: 1;
  padding: 11px 12px;
  border: 2px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--surface);
  color: var(--text);
  font-size: 0.88rem;
  outline: none;
  transition: border-color var(--transition);
  min-width: 0;
}
.date-input:focus { border-color: var(--primary); }

.time-input {
  padding: 11px 10px;
  border: 2px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--surface);
  color: var(--text);
  font-size: 0.88rem;
  outline: none;
  transition: border-color var(--transition);
  width: 108px;
  flex-shrink: 0;
}
.time-input:focus { border-color: var(--primary); }

.modal-datetime-row {
  display: flex;
  gap: 8px;
  margin-top: 10px;
}
.modal-datetime-row .date-input { flex: 1; }
.modal-datetime-row .time-input { width: 108px; flex-shrink: 0; }

.datetime-group {
  display: flex;
  gap: 8px;
  flex: 1;
  min-width: 0;
}

.datetime-field {
  display: flex;
  flex-direction: column;
  gap: 4px;
  flex: 1;
  min-width: 0;
}

.datetime-label {
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--text-muted);
  padding-left: 2px;
}

.datetime-field .date-input,
.datetime-field .time-input {
  width: 100%;
  flex: unset;
}

.add-btn {
  padding: 12px 20px;
  background: linear-gradient(135deg, var(--primary), #8B5CF6);
  color: #fff;
  border: none;
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  font-weight: 700;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 6px;
  white-space: nowrap;
  transition: transform var(--transition), box-shadow var(--transition);
  box-shadow: 0 4px 14px rgba(108,99,255,0.35);
}
.add-btn:hover { transform: translateY(-1px); box-shadow: 0 6px 20px rgba(108,99,255,0.45); }
.add-btn:active { transform: scale(0.97); }
.add-btn-icon { font-size: 1.2rem; font-weight: 400; }

/* ===== Filter Section ===== */
.filter-section {
  padding: 14px 16px 0;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.search-box {
  display: flex;
  align-items: center;
  background: var(--surface);
  border: 2px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0 12px;
  gap: 8px;
  transition: border-color var(--transition);
}
.search-box:focus-within { border-color: var(--primary); }
.search-icon { font-size: 1rem; color: var(--text-muted); }
.search-input {
  flex: 1;
  padding: 11px 0;
  border: none;
  background: transparent;
  color: var(--text);
  font-size: 0.9rem;
  outline: none;
}
.search-input::placeholder { color: var(--text-muted); }

.filter-tabs {
  display: flex;
  gap: 6px;
  overflow-x: auto;
  padding-bottom: 2px;
  scrollbar-width: none;
}
.filter-tabs::-webkit-scrollbar { display: none; }

.filter-btn {
  padding: 7px 14px;
  border: 2px solid var(--border);
  border-radius: 99px;
  background: var(--surface);
  color: var(--text-muted);
  font-size: 0.82rem;
  font-weight: 600;
  cursor: pointer;
  white-space: nowrap;
  transition: all var(--transition);
}
.filter-btn:hover { border-color: var(--primary); color: var(--primary); }
.filter-btn.active {
  background: var(--primary);
  border-color: var(--primary);
  color: #fff;
  box-shadow: 0 2px 10px rgba(108,99,255,0.3);
}

/* ===== Task List ===== */
.task-list-container {
  flex: 1;
  padding: 14px 16px;
  overflow-y: auto;
}

.task-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

/* ===== Swipe Wrapper ===== */
.swipe-wrapper {
  position: relative;
  border-radius: var(--radius);
  overflow: hidden;
  animation: slideIn 0.25s ease;
}

.swipe-bg {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  border-radius: var(--radius);
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.15s ease;
}

.swipe-bg.done-bg {
  background: #e8e8e8;
  justify-content: flex-start;
  padding-left: 20px;
}
[data-theme="dark"] .swipe-bg.done-bg { background: #3a3a4a; }

.swipe-bg.delete-bg {
  background: rgba(255, 107, 107, 0.2);
  justify-content: flex-end;
  padding-right: 20px;
}

.swipe-bg-icon {
  font-size: 1.4rem;
  font-weight: 700;
}

.swipe-bg.done-bg .swipe-bg-label,
.swipe-bg.delete-bg .swipe-bg-label {
  font-size: 0.8rem;
  font-weight: 700;
  margin: 0 6px;
}

.swipe-bg.done-bg .swipe-bg-label { color: #888; }
.swipe-bg.delete-bg .swipe-bg-label { color: var(--danger); }

/* ===== Task Item ===== */
.task-item {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 14px;
  display: flex;
  align-items: flex-start;
  gap: 12px;
  box-shadow: var(--shadow-sm);
  border: 2px solid transparent;
  transition: box-shadow var(--transition), border-color var(--transition);
  position: relative;
  will-change: transform;
  touch-action: pan-y;
  cursor: grab;
  user-select: none;
}

.task-item.dragging {
  opacity: 0.5;
  cursor: grabbing;
  box-shadow: var(--shadow);
}

.task-item.drag-over {
  border-color: var(--primary);
  box-shadow: var(--shadow);
}

.task-item::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 4px;
}

.task-item.priority-high::before { background: var(--high); }
.task-item.priority-medium::before { background: var(--medium); }
.task-item.priority-low::before { background: var(--low); }

.task-item:hover {
  border-color: var(--primary-light);
  box-shadow: var(--shadow);
  transform: translateY(-1px);
}

.task-item.completed { opacity: 0.6; }
.task-item.completed .task-text {
  text-decoration: line-through;
  color: var(--text-muted);
}

.task-checkbox {
  width: 22px;
  height: 22px;
  border: 2.5px solid var(--border);
  border-radius: 50%;
  cursor: pointer;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition);
  margin-top: 1px;
  background: var(--surface);
}
.task-checkbox:hover { border-color: var(--primary); background: var(--primary-light); }
.task-checkbox.checked { background: var(--primary); border-color: var(--primary); }
.task-checkbox.checked::after { content: '✓'; color: #fff; font-size: 0.8rem; font-weight: 700; }

.task-content { flex: 1; min-width: 0; }

.task-text {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text);
  line-height: 1.4;
  word-break: break-word;
  transition: color var(--transition);
}

.task-meta {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-top: 5px;
  flex-wrap: wrap;
}

.priority-badge {
  font-size: 0.7rem;
  font-weight: 700;
  padding: 2px 8px;
  border-radius: 99px;
  text-transform: uppercase;
  letter-spacing: 0.4px;
}
.priority-badge.high { background: rgba(255,107,107,0.15); color: var(--high); }
.priority-badge.medium { background: rgba(255,179,71,0.15); color: #d4900a; }
.priority-badge.low { background: rgba(67,217,173,0.15); color: #1fa87a; }
[data-theme="dark"] .priority-badge.medium { color: var(--medium); }
[data-theme="dark"] .priority-badge.low { color: var(--low); }

.due-date {
  font-size: 0.72rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 3px;
}
.due-date.overdue { color: var(--danger); font-weight: 600; }

.task-actions { display: flex; gap: 4px; flex-shrink: 0; }

.action-btn {
  width: 32px;
  height: 32px;
  border: none;
  border-radius: 8px;
  background: var(--surface2);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.9rem;
  transition: all var(--transition);
}
.action-btn:hover { transform: scale(1.1); }
.action-btn.edit:hover { background: var(--primary-light); }
.action-btn.delete:hover { background: rgba(255,107,107,0.15); }

/* ===== Empty State ===== */
.empty-state {
  display: none;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 48px 24px;
  text-align: center;
}
.empty-state.visible { display: flex; }
.empty-icon { font-size: 3.5rem; margin-bottom: 14px; opacity: 0.6; }
.empty-title { font-size: 1.1rem; font-weight: 700; color: var(--text); margin-bottom: 6px; }
.empty-sub { font-size: 0.88rem; color: var(--text-muted); }

/* ===== Footer ===== */
.app-footer {
  padding: 12px 16px;
  display: flex;
  gap: 10px;
  border-top: 1px solid var(--border);
  background: var(--surface);
}

.footer-btn {
  flex: 1;
  padding: 11px;
  border: 2px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--surface2);
  color: var(--text-muted);
  font-size: 0.82rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
}
.footer-btn:hover { border-color: var(--primary); color: var(--primary); background: var(--primary-light); }
.footer-btn.danger:hover { border-color: var(--danger); color: var(--danger); background: rgba(255,107,107,0.08); }

/* ===== Modal ===== */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 999;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition);
  padding: 20px;
  backdrop-filter: blur(4px);
}
.modal-overlay.open { opacity: 1; pointer-events: all; }

.modal {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 24px;
  width: 100%;
  max-width: 400px;
  box-shadow: 0 20px 60px rgba(0,0,0,0.25);
  transform: scale(0.92) translateY(20px);
  transition: transform var(--transition);
}
.modal-overlay.open .modal { transform: scale(1) translateY(0); }

.modal-title { font-size: 1.15rem; font-weight: 800; margin-bottom: 14px; color: var(--text); }

.modal-actions { display: flex; gap: 10px; margin-top: 16px; }

.modal-btn {
  flex: 1;
  padding: 12px;
  border: none;
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  font-weight: 700;
  cursor: pointer;
  transition: all var(--transition);
}
.modal-btn.cancel { background: var(--surface2); color: var(--text-muted); }
.modal-btn.cancel:hover { background: var(--border); }
.modal-btn.save {
  background: linear-gradient(135deg, var(--primary), #8B5CF6);
  color: #fff;
  box-shadow: 0 4px 14px rgba(108,99,255,0.35);
}
.modal-btn.save:hover { transform: translateY(-1px); }

/* ===== Toast ===== */
.toast {
  position: fixed;
  bottom: calc(env(safe-area-inset-bottom, 0px) + 80px);
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: #1E1E2E;
  color: #fff;
  padding: 12px 22px;
  border-radius: 99px;
  font-size: 0.88rem;
  font-weight: 600;
  opacity: 0;
  pointer-events: none;
  transition: all 0.3s ease;
  z-index: 9999;
  white-space: nowrap;
  box-shadow: 0 4px 20px rgba(0,0,0,0.3);
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

/* ===== Animations ===== */
@keyframes slideIn {
  from { opacity: 0; transform: translateY(12px); }
  to { opacity: 1; transform: translateY(0); }
}
@keyframes fadeOut {
  to { opacity: 0; transform: scale(0.9); }
}
.task-item.removing { animation: fadeOut 0.2s ease forwards; }

/* ===== Scrollbar ===== */
::-webkit-scrollbar { width: 4px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 99px; }

/* ===== Responsive ===== */
@media (max-width: 360px) {
  .app-header h1 { font-size: 1.3rem; }
  .stat-number { font-size: 1.2rem; }
  .add-btn { padding: 12px 14px; font-size: 0.88rem; }
}