:root {
  --bg: #f5f7fb;
  --card: #ffffff;
  --text: #1f2937;
  --muted: #6b7280;
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --border: #dbe3ee;
  --success: #15803d;
  --danger: #b91c1c;
  --shadow: 0 10px 25px rgba(0, 0, 0, 0.06);
}

body.dark {
  --bg: #111827;
  --card: #1f2937;
  --text: #f9fafb;
  --muted: #cbd5e1;
  --primary: #60a5fa;
  --primary-hover: #3b82f6;
  --border: #334155;
  --success: #4ade80;
  --danger: #f87171;
  --shadow: 0 10px 25px rgba(0, 0, 0, 0.25);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  background-color: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

.container {
  width: min(1100px, 92%);
  margin: 0 auto;
}

.site-header {
  background: var(--card);
  border-bottom: 1px solid var(--border);
  padding: 1rem 0;
}

.header-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
}

.tagline {
  margin: 0.25rem 0 0;
  color: var(--muted);
}

.main-nav {
  background: var(--card);
  border-bottom: 1px solid var(--border);
}

.nav-links {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
  padding: 1rem 0;
}

.nav-btn,
.primary-btn,
.secondary-btn {
  border: none;
  border-radius: 10px;
  padding: 0.8rem 1rem;
  cursor: pointer;
  font-size: 1rem;
  transition: 0.2s ease;
}

.nav-btn {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border);
}

.nav-btn.active,
.nav-btn:hover {
  background: var(--primary);
  color: white;
  border-color: var(--primary);
}

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

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

.secondary-btn {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border);
}

.secondary-btn:hover {
  background: rgba(37, 99, 235, 0.08);
}

main {
  padding: 2rem 0 3rem;
}

.view {
  display: none;
}

.active-view {
  display: block;
}

.hero-card,
.card,
.stat-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 18px;
  box-shadow: var(--shadow);
}

.hero-card {
  padding: 1.5rem;
  margin-bottom: 1.5rem;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.stat-card {
  padding: 1.25rem;
  text-align: center;
}

.stat-card h3 {
  margin-top: 0;
  font-size: 1rem;
  color: var(--muted);
}

.stat-card p {
  margin-bottom: 0;
  font-size: 2rem;
  font-weight: bold;
}

.card {
  padding: 1.5rem;
}

.grid-two {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
}

.form-group {
  display: flex;
  flex-direction: column;
  margin-bottom: 1rem;
}

label {
  margin-bottom: 0.35rem;
  font-weight: bold;
}

input,
select,
textarea {
  width: 100%;
  padding: 0.85rem;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: transparent;
  color: var(--text);
  font: inherit;
}

.form-message {
  min-height: 1.2rem;
  margin-bottom: 1rem;
  font-weight: bold;
}

.toolbar {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 1rem;
}

.toolbar-group {
  display: flex;
  flex-direction: column;
  min-width: 180px;
}

.task-list,
.task-preview-list {
  display: grid;
  gap: 1rem;
}

.task-item {
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 1rem;
  background: rgba(255, 255, 255, 0.02);
}

.task-item h3 {
  margin-top: 0;
  margin-bottom: 0.5rem;
}

.task-meta {
  color: var(--muted);
  font-size: 0.95rem;
}

.task-notes {
  margin: 0.75rem 0;
}

.task-actions {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
  margin-top: 1rem;
}

.badge {
  display: inline-block;
  padding: 0.3rem 0.65rem;
  border-radius: 999px;
  font-size: 0.85rem;
  font-weight: bold;
  margin-right: 0.4rem;
  margin-top: 0.4rem;
}

.badge.high {
  background: rgba(185, 28, 28, 0.12);
  color: var(--danger);
}

.badge.medium {
  background: rgba(37, 99, 235, 0.12);
  color: var(--primary);
}

.badge.low {
  background: rgba(21, 128, 61, 0.12);
  color: var(--success);
}

.badge.completed {
  background: rgba(21, 128, 61, 0.12);
  color: var(--success);
}

.badge.overdue {
  background: rgba(185, 28, 28, 0.12);
  color: var(--danger);
}

.empty-message {
  color: var(--muted);
}

.timer-card {
  max-width: 650px;
  margin: 0 auto;
  text-align: center;
}

.timer-display {
  font-size: 4rem;
  font-weight: bold;
  margin: 1.5rem 0;
}

.timer-controls {
  display: flex;
  justify-content: center;
  gap: 1rem;
  flex-wrap: wrap;
}

.timer-note {
  color: var(--muted);
  margin-top: 1rem;
}

.site-footer {
  border-top: 1px solid var(--border);
  background: var(--card);
  padding: 1rem 0;
  text-align: center;
  color: var(--muted);
}

@media (max-width: 900px) {
  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .grid-two {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 600px) {
  .header-inner {
    flex-direction: column;
    align-items: flex-start;
  }

  .stats-grid {
    grid-template-columns: 1fr;
  }

  .timer-display {
    font-size: 3rem;
  }

  .nav-links {
    flex-direction: column;
  }
}