@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;600;700&display=swap');

:root {
  --primary: #2563eb;
  --secondary: #f1f5f9;
  --accent: #22c55e;
  --danger: #ef4444;
  --bg: #ffffff;
  --text: #1e293b;
  --radius: 0.75rem;
  --shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

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

html, body {
  height: 100%;
  font-family: 'Inter', system-ui, sans-serif;
  background-color: var(--secondary);
  color: var(--text);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-start;
  padding: 2rem 1rem;
}

body {
  min-height: 100vh;
}

.todo-container {
  background: var(--bg);
  width: 100%;
  max-width: 500px;
  border-radius: var(--radius);
  padding: 2rem;
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  margin-bottom: auto;
}

.todo-title {
  font-size: 2rem;
  font-weight: 700;
  text-align: center;
  color: var(--primary);
}

.task-form {
  display: flex;
  gap: 0.5rem;
}

#task-input {
  flex: 1;
  padding: 0.75rem;
  border: 2px solid #e2e8f0;
  border-radius: var(--radius);
  font-size: 1rem;
  transition: border-color 0.3s;
}

#task-input:focus {
  border-color: var(--primary);
  outline: none;
}

#task-submit {
  padding: 0.75rem 1.25rem;
  background: var(--primary);
  color: #fff;
  border: none;
  border-radius: var(--radius);
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s, transform 0.2s;
}

#task-submit:hover {
  background: #1d4ed8;
  transform: scale(1.05);
}

.filters {
  display: flex;
  justify-content: space-between;
  gap: 0.5rem;
}

.filter-btn {
  flex: 1;
  padding: 0.5rem;
  background: none;
  border: none;
  border-radius: var(--radius);
  font-weight: 600;
  cursor: pointer;
  color: var(--text);
  transition: background 0.2s;
}

.filter-btn:hover {
  background: #e2e8f0;
}

.filter-btn.active {
  background: var(--primary);
  color: #fff;
}

.task-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.task-item {
  background: var(--secondary);
  padding: 1rem;
  border-radius: var(--radius);
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: background 0.2s, transform 0.2s;
  position: relative;
}

.task-item:hover {
  transform: translateX(4px);
}

.task-item.completed {
  background: #d1fae5;
}

.task-text {
  flex: 1;
  font-size: 1rem;
  cursor: pointer;
  transition: color 0.3s;
  word-break: break-word;
}

.task-item.completed .task-text {
  text-decoration: line-through;
  color: #065f46;
}

.complete-btn,
.delete-btn {
  background: none;
  border: none;
  font-size: 1.2rem;
  cursor: pointer;
  margin-left: 0.5rem;
  transition: transform 0.2s;
}

.complete-btn {
  color: var(--accent);
}

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

.complete-btn:hover,
.delete-btn:hover {
  transform: scale(1.2);
}

.task-item.enter {
  animation: fadeIn 0.3s ease-out forwards;
}

.task-item.exit {
  animation: fadeOut 0.3s ease-in forwards;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(-8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeOut {
  from {
    opacity: 1;
    height: auto;
    margin-bottom: 0.75rem;
  }
  to {
    opacity: 0;
    height: 0;
    margin: 0;
    padding: 0;
  }
}

/* Modo Oscuro */
body.dark {
  background-color: #0f172a;
  color: #f8fafc;
}

body.dark .todo-container {
  background: #1e293b;
  color: #f8fafc;
}

body.dark input,
body.dark button,
body.dark .task-item {
  background-color: #334155;
  color: #f8fafc;
  border-color: #475569;
}

body.dark .task-item.completed {
  background: #14532d;
}

body.dark .task-item.completed .task-text {
  color: #a7f3d0;
}

body.dark .filter-btn {
  color: #f8fafc;
}

body.dark .filter-btn.active {
  background: #2563eb;
  color: #fff;
}

body.dark #task-submit:hover {
  background: #1e40af;
}

/* Footer */
.footer {
  margin-top: 2rem;
  padding: 1rem 0;
  text-align: center;
  opacity: 0.75;
  width: 100%;
}

.footer .social-links {
  display: flex;
  justify-content: center;
  align-items: center;
}

.footer .social-links img {
  width: 56px;
  height: auto;
  transition: transform 0.2s ease-in-out;
}

.footer .social-links a:hover img {
  transform: scale(1.2);
}

/* Botón modo oscuro */
#dark-toggle {
  position: fixed;
  top: 1rem;
  right: 1rem;
  background: transparent;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  z-index: 999;
  color: inherit;
}