:root {
  --font-family: "Josefin Sans", sans-serif;
  --font-size-sm: 1.2rem;
  --font-size-md: 1.6rem;
  --font-size-lg: 2.4rem;
  --font-size-xl: 4rem;
  --font-weight-regular: 400;
  --font-weight-bold: 700;

  --space-xs: 0.8rem;
  --space-sm: 1.2rem;
  --space-md: 1.6rem;
  --space-lg: 2.4rem;
  --space-xl: 4rem;

  --border-radius: 6px;
  --transition: 0.2s ease;

  --color-primary-blue: #3a7bfd;
  --gradient: linear-gradient(135deg, #5f2c82, #49a09d);

  --color-bg-dark: #171823;
  --color-card-dark: #25273c;
  --color-border-dark: #393a4c;
  --color-text-dark: #c8cbe7;
  --color-text-muted-dark: #777a92;

  --color-bg-light: #f2f2f2;
  --color-card-light: #ffffff;
  --color-border-light: #e3e4f1;
  --color-text-light: #494c6b;
  --color-text-muted-light: #9495a5;
}

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

body {
  font-family: var(--font-family);
  background-color: var(--color-bg-light);
  color: var(--color-text-light);
}

body.App--isDark {
  background-color: var(--color-bg-dark);
  color: var(--color-text-dark);
}

/* Header */
.Header {
  display: flex;
  justify-content: center;
  align-items: flex-start;
  height: 320px;
  padding-top: 5rem;
  position: relative;
  background-image: url("../images/bg-desktop-light.jpg");
  background-size: cover;
  background-position: center;
}

.App--isDark .Header {
  background-image: url("../images/bg-desktop-dark.jpg");
}

.Header__content {
  width: 100%;
  max-width: 540px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  z-index: 2;
}

.Header__title {
  font-size: var(--font-size-lg);
  letter-spacing: 1rem;
  font-weight: var(--font-weight-bold);
  color: white;
}

.Header__themeToggle {
  width: 26px;
  height: 26px;
  background: url("../images/icon-moon.svg") no-repeat center;
  border: none;
  cursor: pointer;
}

.App--isDark .Header__themeToggle {
  background: url("../images/icon-sun.svg") no-repeat center;
}

/* Input */
.Main {
  position: relative;
  z-index: 5;
}

.TodoInput {
  max-width: 540px;
  margin: -10rem auto var(--space-md);
  display: flex;
  align-items: center;
  gap: 1.5rem;
  background: var(--color-card-light);
  padding: 1.5rem;
  border-radius: var(--border-radius);
  box-shadow: 0 25px 50px rgba(0, 0, 0, 0.2);
}

.TodoInput {
  height: 60px;
}

.App--isDark .TodoInput {
  background: var(--color-card-dark);
}

.TodoInput__circle {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  border: 1px solid var(--color-border-light);
  flex-shrink: 0;
}

.App--isDark .TodoInput__circle {
  border: 1px solid var(--color-border-dark);
}

.TodoInput__circle.active {
  background: var(--gradient);
  border: none;
}

.TodoInput__field {
  flex: 1;
  border: none;
  outline: none;
  font-size: var(--font-size-sm);
  background: transparent;
  color: inherit;
  line-height: 1.5;
}

/* Todo List */
.TodoList {
  max-width: 540px;
  margin: 0 auto var(--space-md);
  background: var(--color-card-light);
  border-radius: var(--border-radius);
  box-shadow: 0 35px 50px rgba(0, 0, 0, 0.2);
}

.App--isDark .TodoList {
  background: var(--color-card-dark);
}

/* Items */
.TodoList__items li {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1.4rem;
  border-bottom: 1px solid var(--color-border-light);
  position: relative;
}

.App--isDark .TodoList__items li {
  border-bottom: 1px solid var(--color-border-dark);
}

/* Checkbox */
.TodoItem__check {
  position: relative;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  border: 1px solid var(--color-border-light);
  background: transparent;
  cursor: pointer;
}

.App--isDark .TodoItem__check {
  border: 1px solid var(--color-border-dark);
}

.TodoItem__check.active {
  background: var(--gradient);
  border: none;
}

/* Text */
.TodoItem__text {
  flex: 1;
  font-size: var(--font-size-md);
}

li.completed .TodoItem__text {
  text-decoration: line-through;
  opacity: 0.5;
}

/* Delete */
.TodoItem__delete {
  width: 18px;
  height: 18px;
  background: url("../images/icon-cross.svg") no-repeat center;
  border: none;
  cursor: pointer;
  opacity: 0;
}

.TodoList__items li:hover .TodoItem__delete {
  opacity: 1;
}

/* Footer */
.TodoList__footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem;
  font-size: var(--font-size-sm);
  color: var(--color-text-muted-light);
}

.App--isDark .TodoList__footer {
  color: var(--color-text-muted-dark);
}

/* Filters */
.TodoList__filters {
  display: flex;
  gap: 1rem;
}

.TodoList__filters button {
  background: none;
  border: none;
  cursor: pointer;
  color: inherit;
}

.TodoList__filters button.active,
.TodoList__filters button:hover {
  color: var(--color-primary-blue);
}

/* Clear */
.TodoList__clear {
  background: none;
  border: none;
  cursor: pointer;
  color: inherit;
}

/* Drag Info */
.DragInfo {
  text-align: center;
  margin-top: 2rem;
  opacity: 0.5;
  font-size: var(--font-size-sm);
}

/* Mobile */
@media (max-width: 600px) {
  .Header {
    background-image: url("../images/bg-mobile-light.jpg");
  }

  .App--isDark .Header {
    background-image: url("../images/bg-mobile-dark.jpg");
  }

  .TodoInput,
  .TodoList {
    margin-left: 1rem;
    margin-right: 1rem;
  }

  .TodoList__footer {
    flex-direction: column;
    gap: 1rem;
  }

  .TodoList__filters {
    position: fixed;
    bottom: 80px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--color-card-light);
    padding: 1rem 2rem;
    border-radius: 10px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.2);
  }

  .App--isDark .TodoList__filters {
    background: var(--color-card-dark);
  }
}

/* Cursor Fix */
.TodoItem__check,
.TodoItem__delete,
.Header__themeToggle,
.TodoList__clear,
.TodoList__filters button {
  cursor: pointer;
}

/* Placeholder */
.TodoInput__field::placeholder {
  color: var(--color-text-muted-light);
}

.App--isDark .TodoInput__field::placeholder {
  color: var(--color-text-muted-dark);
}

/* Hover */
.TodoList__items li:hover {
  background: rgba(0, 0, 0, 0.03);
}

.App--isDark .TodoList__items li:hover {
  background: rgba(255, 255, 255, 0.03);
}

/* Animation */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.TodoList__items li {
  animation: fadeIn 0.3s ease;
}

/* Delete button UX */
.TodoItem__delete {
  opacity: 0.3;
  transition: 0.2s ease;
}

.TodoList__items li:hover .TodoItem__delete {
  opacity: 1;
}

/* Checkbox active */
.TodoItem__check.active {
  background: var(--gradient);
  border: none;
  position: relative;
}

.TodoItem__check.active::after {
  content: "✔";
  color: white;
  font-size: 12px;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}