:root {
  --bg: #f6f7f9;
  --card: #ffffff;
  --muted: #6b7280;
  --accent: #2563eb;
  --danger: #ef4444;
  --shadow: 0 6px 18px rgba(16, 24, 40, 0.06);
  --radius: 12px;
  --gap: 12px;
  --pad: 18px;
  --max-width: 520px;
  --font: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial;
}

* {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
}

body {
  margin: 0;
  font-family: var(--font);
  background: linear-gradient(180deg, #fbfdff, var(--bg));
  color: #0f172a;
  -webkit-font-smoothing: antialiased;
  display: flex;
  justify-content: center;
  align-items: flex-start;
  padding: 40px 20px;
  min-height: 100vh;
}

.todo-container {
  width: 100%;
  max-width: var(--max-width);
  background: var(--card);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  padding-bottom: 20px;
  height: auto;
}

.todo-header {
  padding: var(--pad);
  border-bottom: 1px solid #eef2f7;
  flex-shrink: 0;
}

.todo-header-form {
  display: flex;
  gap: var(--gap);
  align-items: center;
}

.todo-header-text-field {
  flex: 1;
  padding: 12px 14px;
  border: 1px solid #e6e9ef;
  border-radius: 10px;
  font-size: 15px;
  outline: none;
  transition: box-shadow 0.15s, border-color 0.15s;
  background: transparent;
}

.todo-header-text-field:focus {
  border-color: rgba(37, 99, 235, 0.25);
  box-shadow: 0 6px 18px rgba(37, 99, 235, 0.06);
}

.todo-header-add-todo-button {
  padding: 10px 14px;
  border-radius: 10px;
  background: var(--accent);
  color: #fff;
  border: 0;
  font-weight: 600;
  cursor: pointer;
  box-shadow: 0 6px 12px rgba(37, 99, 235, 0.08);
  transition: transform 0.08s ease, opacity 0.12s;
}

.todo-header-add-todo-button:active {
  transform: translateY(1px);
}

.todo-header-add-todo-button:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.todo-body {
  flex: 1;
  overflow-y: auto;
  padding: 14px;
  min-height: 0;
}

.todo-body-list {
  list-style: none;
  margin: 0;
  padding: 0 4px 10px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.todo-body-list li {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 12px;
  border-radius: 10px;
  background: linear-gradient(180deg, rgba(0, 0, 0, 0.01), transparent);
  border: 1px solid #f1f3f6;
  font-size: 15px;
  color: #0b1220;
  word-break: break-word;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
}

.todo-body-list button {
  border: 0;
  background: transparent;
  cursor: pointer;
  font-size: 16px;
  padding: 6px;
  border-radius: 8px;
  transition: background 0.12s, transform 0.08s;
  flex-shrink: 0;
}

.todo-body-list button:hover {
  background: rgba(0, 0, 0, 0.04);
}

.todo-body-list button:active {
  transform: translateY(1px);
}

.todo-body-list:empty::before {
  content: 'No todos yet — add your first task';
  display: block;
  color: var(--muted);
  padding: 18px;
  text-align: center;
}

@media (max-width: 420px) {
  body {
    padding: 28px 12px;
  }
  .todo-header {
    padding: 14px;
  }
  .todo-header-text-field {
    font-size: 14px;
  }
  .todo-header-add-todo-button {
    padding: 9px 12px;
  }
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f172a;
    --card: #1e293b;
    --muted: #9ca3af;
    --accent: #3b82f6;
    --danger: #f87171;
    --shadow: 0 6px 18px rgba(0, 0, 0, 0.4);
  }

  body {
    background: linear-gradient(180deg, #0b1220, var(--bg));
    color: #f9fafb;
  }

  .todo-container {
    background: var(--card);
    box-shadow: var(--shadow);
  }

  .todo-header {
    border-bottom: 1px solid #334155;
  }

  .todo-header-text-field {
    border: 1px solid #334155;
    background: #1e293b;
    color: #f9fafb;
  }

  .todo-header-text-field::placeholder {
    color: #64748b;
  }

  .todo-body-list li {
    border: 1px solid #334155;
    background: linear-gradient(180deg, rgba(255, 255, 255, 0.02), transparent);
    color: #f1f5f9;
  }

  .todo-body-list button:hover {
    background: rgba(255, 255, 255, 0.08);
  }

  .todo-body-list:empty::before {
    color: var(--muted);
  }
}