:root {
  --bg: #f4f5f7;
  --card: #ffffff;
  --text: #1f2933;
  --muted: #9aa5b1;
  --primary: #4f46e5;
  --primary-dark: #4338ca;
  --danger: #ef4444;
  --border: #e4e7eb;
  --done: #cbd2d9;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Malgun Gothic",
    sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  padding: 40px 16px;
}

.app {
  width: 100%;
  max-width: 480px;
  background: var(--card);
  border-radius: 16px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
  overflow: hidden;
}

.app__header {
  padding: 28px 24px 20px;
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  color: #fff;
}

.app__header h1 {
  font-size: 1.6rem;
  font-weight: 700;
}

.app__date {
  margin-top: 4px;
  font-size: 0.85rem;
  opacity: 0.85;
}

.todo-form {
  display: flex;
  gap: 8px;
  padding: 20px 24px 12px;
}

.todo-form__input {
  flex: 1;
  padding: 12px 14px;
  border: 1px solid var(--border);
  border-radius: 10px;
  font-size: 0.95rem;
  outline: none;
  transition: border-color 0.15s;
}

.todo-form__input:focus {
  border-color: var(--primary);
}

.todo-form__btn {
  padding: 0 18px;
  border: none;
  border-radius: 10px;
  background: var(--primary);
  color: #fff;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s;
}

.todo-form__btn:hover {
  background: var(--primary-dark);
}

.filters {
  display: flex;
  gap: 6px;
  padding: 4px 24px 12px;
}

.filters__btn {
  flex: 1;
  padding: 8px;
  border: 1px solid var(--border);
  background: transparent;
  border-radius: 8px;
  font-size: 0.85rem;
  color: var(--muted);
  cursor: pointer;
  transition: all 0.15s;
}

.filters__btn.is-active {
  background: var(--primary);
  border-color: var(--primary);
  color: #fff;
  font-weight: 600;
}

.todo-list {
  list-style: none;
  padding: 0 12px;
}

.todo-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px;
  border-radius: 10px;
  transition: background 0.15s;
}

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

.todo-item__check {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
  cursor: pointer;
  accent-color: var(--primary);
}

.todo-item__text {
  flex: 1;
  font-size: 0.95rem;
  word-break: break-word;
}

.todo-item.is-done .todo-item__text {
  color: var(--done);
  text-decoration: line-through;
}

.todo-item__delete {
  border: none;
  background: transparent;
  color: var(--muted);
  font-size: 1.2rem;
  line-height: 1;
  cursor: pointer;
  opacity: 0;
  transition: opacity 0.15s, color 0.15s;
}

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

.todo-item__delete:hover {
  color: var(--danger);
}

.empty {
  text-align: center;
  color: var(--muted);
  padding: 32px 24px;
  font-size: 0.95rem;
  display: none;
}

.app__footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 24px 24px;
  font-size: 0.85rem;
  color: var(--muted);
}

.clear-btn {
  border: none;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  transition: color 0.15s;
}

.clear-btn:hover {
  color: var(--danger);
}