/* =========================================================
   TaskFlow — style.css
   A clean, modern to-do list UI
   ========================================================= */

/* ---------- Google Fonts ---------- */
@import url('https://fonts.googleapis.com/css2?family=DM+Sans:wght@300;400;500;600&family=DM+Mono:wght@400;500&display=swap');

/* ---------- CSS Variables ---------- */
:root {
  --bg:          #f5f4f0;
  --surface:     #ffffff;
  --border:      #e8e6e0;
  --accent:      #2a6ef5;
  --accent-dark: #1a52c4;
  --danger:      #e74c3c;
  --success:     #27ae60;
  --text-primary:   #1a1a2e;
  --text-secondary: #6b6b80;
  --text-muted:     #a8a8b8;
  --shadow:      0 4px 24px rgba(0,0,0,.07);
  --radius:      14px;
  --radius-sm:   8px;
  --transition:  .2s ease;
}

/* ---------- Reset ---------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: 'DM Sans', sans-serif;
  background: var(--bg);
  color: var(--text-primary);
  min-height: 100vh;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding: 48px 16px 80px;
}

/* ---------- App Container ---------- */
.app-wrapper {
  width: 100%;
  max-width: 560px;
  display: flex;
  flex-direction: column;
  gap: 0;
}

/* ---------- Header ---------- */
.app-header {
  background: var(--surface);
  border-radius: var(--radius) var(--radius) 0 0;
  padding: 32px 28px 24px;
  border: 1px solid var(--border);
  border-bottom: none;
}

.header-top {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 20px;
}

.app-title {
  font-size: 1.75rem;
  font-weight: 600;
  letter-spacing: -0.04em;
  color: var(--text-primary);
}

.task-counter {
  font-family: 'DM Mono', monospace;
  font-size: .8rem;
  color: var(--text-muted);
}

/* ---------- Add Task Form ---------- */
.add-task-form {
  display: flex;
  gap: 10px;
}

.task-input {
  flex: 1;
  padding: 12px 16px;
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  font-family: inherit;
  font-size: .95rem;
  background: var(--bg);
  color: var(--text-primary);
  outline: none;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.task-input::placeholder { color: var(--text-muted); }

.task-input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(42,110,245,.12);
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 12px 20px;
  border: none;
  border-radius: var(--radius-sm);
  font-family: inherit;
  font-size: .9rem;
  font-weight: 500;
  cursor: pointer;
  transition: background var(--transition), transform var(--transition), opacity var(--transition);
  white-space: nowrap;
}

.btn:active { transform: scale(.97); }

.btn-add {
  background: var(--accent);
  color: #fff;
}
.btn-add:hover { background: var(--accent-dark); }

.btn-icon { font-size: 1.1rem; line-height: 1; }

/* ---------- Error Message ---------- */
.error-msg {
  font-size: .82rem;
  color: var(--danger);
  margin-top: 10px;
  min-height: 18px;
  font-weight: 500;
  transition: opacity var(--transition);
}

/* ---------- Filter Bar ---------- */
.filter-bar {
  display: flex;
  background: var(--surface);
  border-left: 1px solid var(--border);
  border-right: 1px solid var(--border);
  padding: 0 28px;
  gap: 4px;
  border-bottom: 1px solid var(--border);
}

.filter-btn {
  padding: 10px 14px;
  border: none;
  background: none;
  font-family: inherit;
  font-size: .88rem;
  font-weight: 500;
  color: var(--text-secondary);
  cursor: pointer;
  position: relative;
  transition: color var(--transition);
}

.filter-btn::after {
  content: '';
  position: absolute;
  bottom: 0; left: 50%; right: 50%;
  height: 2px;
  background: var(--accent);
  border-radius: 2px 2px 0 0;
  transition: left var(--transition), right var(--transition);
}

.filter-btn.active { color: var(--accent); }
.filter-btn.active::after { left: 0; right: 0; }
.filter-btn:hover:not(.active) { color: var(--text-primary); }

/* ---------- Task List ---------- */
.task-list {
  list-style: none;
  background: var(--surface);
  border-left: 1px solid var(--border);
  border-right: 1px solid var(--border);
}

/* ---------- Task Item ---------- */
.task-item {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 16px 28px;
  border-bottom: 1px solid var(--border);
  animation: fadeSlideIn .25s ease both;
  transition: background var(--transition), opacity var(--transition);
}

.task-item:hover { background: #fafaf8; }

/* Fade-in animation */
@keyframes fadeSlideIn {
  from { opacity: 0; transform: translateY(-8px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* Custom Checkbox */
.task-checkbox {
  appearance: none;
  width: 20px;
  height: 20px;
  min-width: 20px;
  border: 2px solid var(--border);
  border-radius: 50%;
  cursor: pointer;
  position: relative;
  transition: border-color var(--transition), background var(--transition);
  flex-shrink: 0;
}

.task-checkbox:hover { border-color: var(--accent); }

.task-checkbox:checked {
  background: var(--success);
  border-color: var(--success);
}

.task-checkbox:checked::after {
  content: '✓';
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: .7rem;
  font-weight: 700;
}

/* Task Text */
.task-text {
  flex: 1;
  font-size: .95rem;
  line-height: 1.5;
  word-break: break-word;
  transition: color var(--transition), text-decoration var(--transition);
}

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

/* Edit Input (inline) */
.task-edit-input {
  flex: 1;
  padding: 4px 10px;
  border: 1.5px solid var(--accent);
  border-radius: var(--radius-sm);
  font-family: inherit;
  font-size: .95rem;
  color: var(--text-primary);
  outline: none;
  box-shadow: 0 0 0 3px rgba(42,110,245,.1);
  background: var(--bg);
}

/* Action Buttons */
.task-actions {
  display: flex;
  gap: 6px;
  opacity: 0;
  transition: opacity var(--transition);
}

.task-item:hover .task-actions,
.task-item:focus-within .task-actions {
  opacity: 1;
}

.action-btn {
  width: 30px;
  height: 30px;
  border: none;
  border-radius: var(--radius-sm);
  background: transparent;
  cursor: pointer;
  font-size: .85rem;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background var(--transition), transform var(--transition);
  color: var(--text-secondary);
}

.action-btn:hover { background: var(--bg); }
.action-btn:active { transform: scale(.9); }

.action-btn.edit:hover { color: var(--accent); }
.action-btn.save:hover { color: var(--success); }
.action-btn.delete:hover { color: var(--danger); }

/* ---------- Empty State ---------- */
.empty-state {
  background: var(--surface);
  border-left: 1px solid var(--border);
  border-right: 1px solid var(--border);
  text-align: center;
  padding: 56px 24px;
  animation: fadeSlideIn .3s ease;
}

.empty-icon {
  font-size: 2.4rem;
  color: var(--border);
  margin-bottom: 12px;
  line-height: 1;
}

.empty-title {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 6px;
}

.empty-sub {
  font-size: .88rem;
  color: var(--text-muted);
}

/* ---------- Footer ---------- */
.app-footer {
  background: var(--surface);
  border: 1px solid var(--border);
  border-top: none;
  border-radius: 0 0 var(--radius) var(--radius);
  padding: 14px 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: .83rem;
  color: var(--text-muted);
}

.btn-clear {
  background: none;
  border: 1px solid var(--border);
  color: var(--text-secondary);
  padding: 6px 14px;
  font-size: .82rem;
  border-radius: var(--radius-sm);
}

.btn-clear:hover {
  background: #fdf0ef;
  border-color: #f5c6c2;
  color: var(--danger);
}

/* ---------- Removing animation ---------- */
.task-item.removing {
  opacity: 0;
  transform: translateX(20px);
  transition: opacity .2s ease, transform .2s ease;
}

/* ---------- Responsive ---------- */
@media (max-width: 480px) {
  body { padding: 24px 10px 60px; }

  .app-header { padding: 24px 18px 18px; }

  .task-item { padding: 14px 18px; }

  .task-actions { opacity: 1; }   /* always visible on mobile */

  .filter-bar { padding: 0 18px; }

  .app-footer { padding: 12px 18px; }

  .add-task-form { flex-direction: column; }

  .btn-add { justify-content: center; }
}