/* =============================================
   CSS RESET & CUSTOM PROPERTIES
   ============================================= */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

/* -----------------------------------------------
   LIGHT THEME (default)
   Primary: #2BAE66  |  Secondary: #2BAE66
----------------------------------------------- */
:root {
  --primary:      #2BAE66;
  --primary-dark: #1f8f50;
  --secondary:    #2BAE66;
  --accent:       #1f8f50;
  --danger:       #ef4444;
  --danger-dark:  #dc2626;
  --success:      #2BAE66;

  --bg:           #f0faf4;
  --bg-card:      #ffffff;
  --bg-section:   #e2f5ea;

  --text:         #0d2b1a;
  --text-muted:   #3d7a55;
  --border:       #b2dfc4;
  --white:        #ffffff;

  --font:         'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  --radius:       12px;
  --radius-sm:    8px;
  --shadow:       0 8px 32px rgba(43, 174, 102, 0.14);
  --transition:   0.3s ease;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font);
  background-color: var(--bg);
  color: var(--text);
  line-height: 1.7;
  min-height: 100vh;
}

ul {
  list-style: none;
}

/* =============================================
   REUSABLE BUTTONS
   ============================================= */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.7rem 1.5rem;
  border-radius: 50px;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  border: 2px solid transparent;
  transition: transform var(--transition),
              box-shadow var(--transition),
              background var(--transition);
}

.btn--primary {
  background: var(--primary);
  color: var(--white);
  border-color: var(--primary);
}

.btn--primary:hover {
  background: var(--primary-dark);
  border-color: var(--primary-dark);
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(43, 174, 102, 0.4);
}

.btn--danger {
  background: var(--danger);
  color: var(--white);
  border-color: var(--danger);
}

.btn--danger:hover {
  background: var(--danger-dark);
  border-color: var(--danger-dark);
  transform: translateY(-2px);
}

.btn--sm {
  padding: 0.4rem 1rem;
  font-size: 0.82rem;
}

/* =============================================
   HEADER
   ============================================= */
.header {
  text-align: center;
  padding: 3rem 2rem 1.5rem;
}

.header__title {
  font-size: clamp(1.8rem, 4vw, 2.4rem);
  font-weight: 800;
  color: var(--text);
  margin-bottom: 0.4rem;
}

.header__subtitle {
  color: var(--text-muted);
  font-size: 0.95rem;
}

/* =============================================
   MAIN WRAPPER
   ============================================= */
.main {
  max-width: 640px;
  margin: 0 auto;
  padding: 0 1.5rem 4rem;
}

/* =============================================
   INPUT SECTION
   ============================================= */
.input-section {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-bottom: 1.25rem;
  box-shadow: var(--shadow);
}

.input-section__form {
  display: flex;
  gap: 0.75rem;
  margin-bottom: 1.25rem;
}

.input-section__field {
  flex: 1;
  padding: 0.75rem 1.1rem;
  background: var(--bg-section);
  border: 1px solid var(--border);
  border-radius: 50px;
  color: var(--text);
  font-family: var(--font);
  font-size: 0.95rem;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.input-section__field:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(43, 174, 102, 0.2);
}

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

/* =============================================
   FILTER BUTTONS
   ============================================= */
.filters {
  display: flex;
  gap: 0.5rem;
}

.filters__btn {
  padding: 0.35rem 1rem;
  border-radius: 50px;
  border: 1px solid var(--border);
  background: transparent;
  color: var(--text-muted);
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition: background var(--transition),
              color var(--transition),
              border-color var(--transition);
}

.filters__btn:hover {
  color: var(--text);
  border-color: var(--primary);
}

.filters__btn--active {
  background: var(--primary);
  color: var(--white);
  border-color: var(--primary);
}

/* =============================================
   TASK LIST SECTION
   ============================================= */
.list-section {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  margin-bottom: 1.25rem;
  min-height: 80px;
}

/* =============================================
   INDIVIDUAL TASK ITEM
   ============================================= */
.todo-item {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--border);
  transition: background var(--transition);
  animation: slideIn 0.25s ease forwards;
}

.todo-item:last-child {
  border-bottom: none;
}

.todo-item:hover {
  background: var(--bg-section);
}

/* Completed state: muted text + strikethrough */
.todo-item--completed .todo-item__text {
  text-decoration: line-through;
  color: var(--text-muted);
}

@keyframes slideIn {
  from { opacity: 0; transform: translateY(-10px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ------ Checkbox ------ */
.todo-item__checkbox {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  border: 2px solid var(--border);
  background: transparent;
  cursor: pointer;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background var(--transition), border-color var(--transition);
  font-size: 0.7rem;
  color: var(--white);
}

.todo-item__checkbox:hover {
  border-color: var(--success);
}

.todo-item--completed .todo-item__checkbox {
  background: var(--success);
  border-color: var(--success);
}

/* ------ Task text (editable on dblclick) ------ */
.todo-item__text {
  flex: 1;
  font-size: 0.97rem;
  color: var(--text);
  word-break: break-word;
  transition: color var(--transition);
}

/* Edit input shown when editing */
.todo-item__edit {
  flex: 1;
  padding: 0.3rem 0.6rem;
  background: var(--bg-section);
  border: 1px solid var(--primary);
  border-radius: var(--radius-sm);
  color: var(--text);
  font-family: var(--font);
  font-size: 0.97rem;
  box-shadow: 0 0 0 3px rgba(43, 174, 102, 0.2);
}

.todo-item__edit:focus {
  outline: none;
}

/* ------ Action buttons (edit / delete) ------ */
.todo-item__actions {
  display: flex;
  gap: 0.4rem;
  opacity: 0;
  transition: opacity var(--transition);
}

.todo-item:hover .todo-item__actions {
  opacity: 1;
}

.todo-item__btn {
  width: 30px;
  height: 30px;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: var(--bg-section);
  color: var(--text-muted);
  font-size: 0.8rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background var(--transition),
              color var(--transition),
              border-color var(--transition),
              transform var(--transition);
}

.todo-item__btn:hover {
  transform: scale(1.15);
}

.todo-item__btn--edit:hover {
  background: var(--primary);
  border-color: var(--primary);
  color: var(--white);
}

.todo-item__btn--delete:hover {
  background: var(--danger);
  border-color: var(--danger);
  color: var(--white);
}

/* =============================================
   EMPTY STATE
   ============================================= */
.empty-state {
  display: none; /* shown via JS */
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 3rem 2rem;
  gap: 0.75rem;
}

.empty-state--visible {
  display: flex;
}

.empty-state__icon {
  font-size: 2.5rem;
}

.empty-state__text {
  color: var(--text-muted);
  font-size: 0.95rem;
}

/* =============================================
   STATS FOOTER
   ============================================= */
.stats {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1.25rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.stats__count {
  color: var(--text-muted);
  font-size: 0.88rem;
}

/* =============================================
   FOOTER
   ============================================= */
.footer {
  background: var(--bg-section);
  border-top: 1px solid var(--border);
  padding: 1.5rem 2rem;
  margin-top: 2rem;
}

.footer__inner {
  max-width: 640px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.footer__logo {
  font-size: 1rem;
  font-weight: 700;
  color: var(--primary);
  letter-spacing: 0.5px;
}

.footer__copy {
  color: var(--text-muted);
  font-size: 0.85rem;
}

/* =============================================
   RESPONSIVE — MOBILE (max 480px)
   ============================================= */
@media (max-width: 480px) {
  .input-section__form {
    flex-direction: column;
  }

  .input-section__field,
  .btn--primary {
    width: 100%;
    border-radius: var(--radius-sm);
    justify-content: center;
  }

  .filters {
    flex-wrap: wrap;
  }

  .todo-item__actions {
    opacity: 1; /* always visible on touch devices */
  }

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