* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: system-ui, 'Segoe UI', 'Helvetica Neue', sans-serif;
  transition: background-color 0.2s ease, border-color 0.2s ease, color 0.2s ease;
}

body {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-gradient);
  padding: 1.5rem;
}

/* Light mode (default) */
:root {
  --bg-gradient: linear-gradient(135deg, #f5f7fa 0%, #e9eef3 100%);
  --card-bg: rgba(255, 255, 255, 0.92);
  --card-shadow: 0 25px 45px -12px rgba(0, 0, 0, 0.25);
  --text-primary: #1e293b;
  --text-secondary: #475569;
  --accent: #6366f1;
  --accent-hover: #4f46e5;
  --input-bg: #ffffff;
  --input-border: #cbd5e1;
  --input-focus: #818cf8;
  --btn-text: white;
  --placeholder: #94a3b8;
  --task-bg: #f8fafc;
  --task-border: #e2e8f0;
  --delete-hover: #ef4444;
}

body.dark {
  --bg-gradient: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
  --card-bg: rgba(30, 41, 59, 0.95);
  --card-shadow: 0 25px 45px -12px rgba(0, 0, 0, 0.5);
  --text-primary: #f1f5f9;
  --text-secondary: #cbd5e1;
  --accent: #818cf8;
  --accent-hover: #a5b4fc;
  --input-bg: #1e293b;
  --input-border: #334155;
  --input-focus: #818cf8;
  --btn-text: #f8fafc;
  --placeholder: #64748b;
  --task-bg: #1e293b;
  --task-border: #334155;
  --delete-hover: #f87171;
}

.card {
  background: var(--card-bg);
  backdrop-filter: blur(4px);
  border-radius: 2rem;
  box-shadow: var(--card-shadow);
  width: 100%;
  max-width: 620px;
  padding: 2.5rem 2.2rem;
  text-align: center;
  border: 1px solid rgba(255, 255, 255, 0.2);
}

.card .input-group {
  margin-top: 2rem;
}

.todo-container {
  max-width: 680px;
  padding: 2rem;
}

h1 {
  font-size: 2.2rem;
  font-weight: 700;
  background: linear-gradient(120deg, var(--accent), #a855f7);
  background-clip: text;
  -webkit-background-clip: text;
  color: transparent;
  margin-bottom: 0.5rem;
}

.sub {
  color: var(--text-secondary);
  margin-bottom: 2.5rem;
  font-size: 0.95rem;
}

.input-group {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  margin-top: 0.8rem;
}

input {
  width: 100%;
  padding: 1.1rem 1.4rem;
  font-size: 1rem;
  background: var(--input-bg);
  border: 1.5px solid var(--input-border);
  border-radius: 2.5rem;
  outline: none;
  color: var(--text-primary);
  transition: all 0.2s;
}

input:focus {
  border-color: var(--input-focus);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.3);
}

input::placeholder {
  color: var(--placeholder);
}

button {
  background: var(--accent);
  color: var(--btn-text);
  border: none;
  padding: 1rem 1.5rem;
  font-size: 1rem;
  font-weight: 600;
  border-radius: 3rem;
  cursor: pointer;
  transition: 0.2s;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
  width: 100%;
}

button:hover {
  background: var(--accent-hover);
  transform: scale(0.98);
}

.theme-toggle {
  position: fixed;
  top: 20px;
  right: 20px;
  background: var(--card-bg);
  border: 1px solid var(--input-border);
  border-radius: 3rem;
  padding: 0.5rem 1rem;
  font-size: 1.2rem;
  cursor: pointer;
  backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  z-index: 100;
  box-shadow: 0 5px 12px rgba(0, 0, 0, 0.1);
}

.theme-toggle span {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-primary);
}

/* Todo specific styles */
.header-section {
  margin-bottom: 1.8rem;
}

.welcome-message {
  color: var(--accent);
  font-weight: 600;
  margin-top: 0.5rem;
  font-size: 1rem;
}

.add-task-section {
  display: flex;
  gap: 0.8rem;
  margin-bottom: 2rem;
  flex-wrap: wrap;
}

.add-task-section input {
  flex: 1;
}

.add-task-section button {
  width: auto;
  padding: 0.9rem 1.8rem;
  white-space: nowrap;
}

.tasks-list {
  max-height: 420px;
  overflow-y: auto;
  margin-bottom: 1.2rem;
  border-radius: 1rem;
}

.empty-state {
  text-align: center;
  padding: 2rem;
  color: var(--text-secondary);
  font-style: italic;
}

.task-item {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  background: var(--task-bg);
  border: 1px solid var(--task-border);
  border-radius: 1.5rem;
  padding: 0.8rem 1rem;
  margin-bottom: 0.7rem;
  transition: all 0.2s;
}

.task-item:hover {
  transform: translateX(4px);
  border-color: var(--accent);
}

.task-check {
  width: 22px;
  height: 22px;
  cursor: pointer;
  accent-color: var(--accent);
}

.task-text {
  flex: 1;
  font-size: 1rem;
  color: var(--text-primary);
  word-break: break-word;
  text-align: left;
  cursor: pointer;
}

.task-text.completed {
  text-decoration: line-through;
  opacity: 0.65;
}

.delete-btn {
  background: transparent;
  color: #ef4444;
  box-shadow: none;
  width: auto;
  padding: 0.4rem 0.8rem;
  font-size: 1.2rem;
  font-weight: normal;
}

.delete-btn:hover {
  background: var(--delete-hover);
  color: white;
  transform: scale(1.02);
}

.task-stats {
  display: flex;
  justify-content: space-between;
  padding-top: 1rem;
  border-top: 1px solid var(--input-border);
  color: var(--text-secondary);
  font-size: 0.85rem;
  font-weight: 500;
}

@media (max-width: 560px) {
  .card {
    padding: 1.5rem;
  }
  .input-group {
    gap: 1.5rem;
  }
  .add-task-section {
    flex-direction: column;
  }
  .add-task-section button {
    width: 100%;
  }
  .task-item {
    flex-wrap: wrap;
  }
}
/* Follow Us Footer */
.app-footer {
    margin-top: 30px;
    padding-top: 20px;
    text-align: center;
    border-top: 1px solid #ddd;
}

body.dark .app-footer {
    border-top-color: #334155;
}

.footer-social {
    margin-bottom: 12px;
    font-size: 14px;
}

.footer-social span {
    margin-right: 12px;
    font-weight: 500;
}

.footer-social a {
    color: #6366f1;
    text-decoration: none;
    margin: 0 10px;
    font-size: 14px;
}

body.dark .footer-social a {
    color: #a5b4fc;
}

.footer-social a:hover {
    text-decoration: underline;
}

.footer-copyright {
    font-size: 11px;
    opacity: 0.6;
}
/* Additional dark mode fixes for footer */
body.dark .footer-social span {
    color: #f1f5f9;
}

body.dark .footer-copyright {
    color: #cbd5e1;
}