/* ===== Global Styles ===== */
:root {
  --primary-blue: #3b82f6;
  --primary-dark: #1d4ed8;
  --text-dark: #1f2937;
  --text-light: #6b7280;
  --bg-light: #f8fafc;
  --bg-white: #ffffff;
  --border-color: #e2e8f0;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --radius-md: 0.5rem;
  --radius-full: 9999px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background-color: var(--bg-light);
  color: var(--text-dark);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

button,
input,
textarea {
  font: inherit;
}

button {
  cursor: pointer;
}

/* ===== Page Layout ===== */
.header {
  background-color: var(--text-dark);
  color: var(--bg-white);
  padding: 1rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: sticky;
  top: 0;
  z-index: 10;
}

.header-logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 700;
  font-size: 1.25rem;
}

.header-logo img {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-md);
}

.header-actions {
  display: flex;
  gap: 0.75rem;
}

.header-actions img {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-full);
  border: 2px solid var(--bg-white);
}

.main {
  flex: 1;
  padding: 1.5rem;
  background-color: var(--bg-white);
  background-image: radial-gradient(var(--border-color) 1px, transparent 1px);
  background-size: 20px 20px;
}

.todo-list {
  list-style: none;
}

.todo-item {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  padding: 0.75rem 0;
  border-bottom: 1px solid var(--border-color);
}

.todo-item:last-child {
  border-bottom: none;
}

.todo-checkbox {
  width: 18px;
  height: 18px;
  margin-top: 0.25rem;
  accent-color: var(--primary-blue);
}

.todo-text {
  flex: 1;
  font-size: 0.9375rem;
  line-height: 1.5;
  color: var(--text-dark);
}

.todo-text.done {
  text-decoration: line-through;
  color: var(--text-light);
}

.add-idea-btn {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  background-color: var(--primary-blue);
  color: var(--bg-white);
  border: none;
  border-radius: var(--radius-full);
  padding: 0.75rem 1.25rem;
  font-size: 0.875rem;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  transition: background-color 0.2s ease, transform 0.2s ease;
}

.add-idea-btn:hover {
  background-color: var(--primary-dark);
  transform: translateY(-1px);
}

@media (max-width: 768px) {
  .main {
    padding: 1rem;
  }

  .header {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.75rem;
  }
}