:root {
  --bg: linear-gradient(135deg, #667eea, #764ba2);
  --card: #ffffff;
  --texto: #333333;
  --texto-suave: #888888;
  --item: #f7f7f9;
  --borda: #e0e0e0;
  --primaria: #764ba2;
  --primaria-hover: #5a3780;
  --perigo: #e74c3c;
}

[data-tema="escuro"] {
  --bg: linear-gradient(135deg, #1e1e2f, #2d2b42);
  --card: #26263a;
  --texto: #f0f0f5;
  --texto-suave: #9a9ab0;
  --item: #32324a;
  --borda: #3d3d5c;
  --primaria: #9d7bd4;
  --primaria-hover: #b192e0;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Segoe UI", system-ui, sans-serif;
}

body {
  background: var(--bg);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: flex-start;
  padding: 40px 16px;
  transition: background 0.3s;
}

.container {
  background: var(--card);
  width: 100%;
  max-width: 480px;
  padding: 28px;
  border-radius: 16px;
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.2);
  transition: background 0.3s;
}

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

h1 {
  color: var(--texto);
  font-size: 24px;
}

.tema {
  background: transparent;
  border: none;
  font-size: 22px;
  cursor: pointer;
  padding: 4px;
}

form {
  display: flex;
  gap: 8px;
  margin-bottom: 16px;
}

input[type="text"] {
  flex: 1;
  padding: 12px;
  border: 2px solid var(--borda);
  border-radius: 8px;
  font-size: 15px;
  outline: none;
  background: var(--item);
  color: var(--texto);
}

input[type="text"]:focus {
  border-color: var(--primaria);
}

button {
  cursor: pointer;
  border: none;
  border-radius: 8px;
  font-size: 15px;
  transition: background 0.2s, color 0.2s;
}

form button {
  padding: 12px 18px;
  background: var(--primaria);
  color: #fff;
}

form button:hover {
  background: var(--primaria-hover);
}

.filtros {
  display: flex;
  gap: 6px;
  margin-bottom: 16px;
}

.filtro {
  flex: 1;
  padding: 8px;
  background: var(--item);
  color: var(--texto-suave);
}

.filtro.ativo {
  background: var(--primaria);
  color: #fff;
}

ul {
  list-style: none;
}

li {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px;
  border-radius: 8px;
  background: var(--item);
  margin-bottom: 8px;
}

li.concluida span.texto {
  text-decoration: line-through;
  color: var(--texto-suave);
}

li input[type="checkbox"] {
  width: 18px;
  height: 18px;
  cursor: pointer;
  accent-color: var(--primaria);
}

span.texto {
  flex: 1;
  cursor: pointer;
  word-break: break-word;
  color: var(--texto);
}

span.texto:focus {
  outline: 2px dashed var(--primaria);
  border-radius: 4px;
}

.remover {
  background: transparent;
  color: var(--perigo);
  padding: 4px 8px;
  font-size: 18px;
}

.remover:hover {
  background: rgba(231, 76, 60, 0.15);
}

.vazio {
  text-align: center;
  color: var(--texto-suave);
  padding: 20px 0;
}

footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 12px;
  font-size: 14px;
  color: var(--texto-suave);
}

.limpar {
  background: transparent;
  color: var(--texto-suave);
  padding: 4px 8px;
  text-decoration: underline;
}

.limpar:hover {
  color: var(--perigo);
}