:root {
  --bg: #0f172a;
  --card: #1e293b;
  --text: #e2e8f0;
  --subtext: #94a3b8;
  --border: #334155;

  --primary: #6366f1;
  --primary-hover: #4f46e5;

  --success: #22c55e;
  --danger: #ef4444;
}


body {
  font-family: "Trebuchet MS", Verdana, sans-serif;
  background: var(--bg);
  color: var(--text);
}


.container {
  max-width: 800px;
  margin: 60px auto;
  padding: 20px;
}


h1 {
  font-size: 2rem;
  margin-bottom: 1rem;
}

h2 {
  font-size: 1.4rem;
  margin-top: 2rem;
  padding-top: 0.5rem;
  border-top: 1px solid var(--border);
}


input {
  flex: 1;
  padding: 6px 10px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--card);
  color: var(--text);
}


#todo-list li,
#completed-list li {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 10px;
  margin-top: 8px;
  transition: 0.2s;
}

#todo-list li:hover {
  transform: translateY(-2px);
  border-color: var(--primary);
}


.due-date {
  font-size: 0.8rem;
  color: var(--subtext);
}


.done,
.delete {
  border: none;
  border-radius: 6px;
  padding: 4px 10px;
  cursor: pointer;
  font-size: 0.8rem;
  transition: 0.2s;
}


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

.done:hover {
  background: var(--primary-hover);
}


.delete {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--subtext);
}

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


#completed-list .done {
  background: transparent;
  color: var(--success);
  cursor: default;
}


.ui-state-highlight {
  height: 40px;
  border: 2px dashed var(--border);
  border-radius: 6px;
}