:root[data-theme="dark"] {
  --bg: #111111;
  --surface: #1a1a1a;
  --surface2: #222222;
  --border: #2e2e2e;
  --text: #e8e8e8;
  --text-muted: #888;
  --accent: #c8f05a;
  --accent-dark: #a8cc3a;
  --danger: #ff4f4f;
  --tag-bg: #2a2a2a;
  --toggle-bg: #333;
  --shadow: 0 4px 24px rgba(0, 0, 0, 0.4);
}
:root[data-theme="light"] {
  --bg: #f4f3ef;
  --surface: #ffffff;
  --surface2: #f0efe9;
  --border: #ddd;
  --text: #111;
  --text-muted: #888;
  --accent: #2d6a1f;
  --accent-dark: #1e4d14;
  --danger: #d93025;
  --tag-bg: #e8e8e2;
  --toggle-bg: #ccc;
  --shadow: 0 4px 24px rgba(0, 0, 0, 0.08);
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: "DM Sans", sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  transition:
    background 0.3s,
    color 0.3s;
}

/* HEADER */
.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 28px 40px;
  border-bottom: 1px solid var(--border);
  background: var(--surface);
  flex-wrap: wrap;
}

.logo {
  text-decoration: none;
  font-family: "Space Mono", monospace;
  font-size: 1.2rem;
  letter-spacing: -0.02em;
  color: var(--text);
}
.logo span {
  color: var(--accent);
}

.site-nav {
  display: flex;
  gap: 14px;
}

.site-nav a {
  color: var(--text-muted);
  text-decoration: none;
  font-family: "Space Mono", monospace;
  font-size: 0.8rem;
  transition: color 0.2s;
}

.site-nav a:hover,
.site-nav a:focus-visible {
  color: var(--text);
}

/* TOGGLE */
.toggle-wrap {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.8rem;
  color: var(--text-muted);
  font-family: "Space Mono", monospace;
}

.toggle {
  position: relative;
  width: 48px;
  height: 26px;
  cursor: pointer;
}
.toggle input {
  display: none;
}
.toggle-track {
  width: 100%;
  height: 100%;
  background: var(--toggle-bg);
  border-radius: 13px;
  transition: background 0.3s;
  position: relative;
}
.toggle-thumb {
  position: absolute;
  top: 3px;
  left: 3px;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--accent);
  transition: transform 0.3s;
}
.toggle input:checked ~ .toggle-track .toggle-thumb {
  transform: translateX(22px);
}

/* MAIN */
main {
  max-width: 860px;
  margin: 0 auto;
  padding: 40px 24px;
}

.skip-link {
  position: absolute;
  top: -40px;
  left: 12px;
  z-index: 1000;
  background: var(--accent);
  color: #111;
  padding: 8px 12px;
  border-radius: 6px;
  font-size: 0.82rem;
  text-decoration: none;
}

.skip-link:focus {
  top: 10px;
}

h1 {
  font-family: "Space Mono", monospace;
  font-size: 2.2rem;
  margin-bottom: 6px;
  line-height: 1.1;
}
.subtitle {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: 12px;
}

.intro-copy {
  color: var(--text-muted);
  line-height: 1.6;
  max-width: 70ch;
  margin-bottom: 36px;
}

/* STATS */
.stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin-bottom: 32px;
}
.stat {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 16px 20px;
  transition:
    background 0.3s,
    border 0.3s;
}
.stat-num {
  font-family: "Space Mono", monospace;
  font-size: 2rem;
  font-weight: 700;
  color: var(--accent);
  line-height: 1;
}
.stat-label {
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-top: 4px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* ADD FORM */
.add-form {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 24px;
  margin-bottom: 28px;
  transition:
    background 0.3s,
    border 0.3s;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 10px;
  margin-bottom: 12px;
}

input[type="text"],
input[type="date"],
select {
  background: var(--surface2);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 8px;
  padding: 11px 14px;
  font-family: "DM Sans", sans-serif;
  font-size: 0.9rem;
  outline: none;
  transition:
    border-color 0.2s,
    background 0.3s;
  width: 100%;
}
input[type="text"]:focus,
input[type="date"]:focus,
select:focus {
  border-color: var(--accent);
}

.form-row2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

button.add-btn {
  background: var(--accent);
  color: #111;
  border: none;
  border-radius: 8px;
  padding: 11px 20px;
  font-family: "Space Mono", monospace;
  font-size: 0.8rem;
  cursor: pointer;
  white-space: nowrap;
  transition:
    background 0.2s,
    transform 0.1s;
  font-weight: 700;
}
button.add-btn:hover {
  background: var(--accent-dark);
  transform: translateY(-1px);
}
button.add-btn:active {
  transform: translateY(0);
}

/* FILTERS */
.filters {
  display: flex;
  gap: 8px;
  margin-bottom: 20px;
  flex-wrap: wrap;
}
.filter-btn {
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text-muted);
  border-radius: 20px;
  padding: 6px 16px;
  font-family: "Space Mono", monospace;
  font-size: 0.72rem;
  cursor: pointer;
  transition: all 0.2s;
}
.filter-btn.active {
  background: var(--accent);
  border-color: var(--accent);
  color: #111;
}

/* TASKS */
.tasks {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.task {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 18px 20px;
  display: flex;
  align-items: flex-start;
  gap: 14px;
  transition:
    all 0.2s,
    background 0.3s;
  animation: slideIn 0.2s ease;
}
@keyframes slideIn {
  from {
    opacity: 0;
    transform: translateY(-8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}
.task:hover {
  border-color: var(--accent);
}
.task.done {
  opacity: 0.5;
}
.task.done .task-title {
  text-decoration: line-through;
}

.task-check {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  border: 2px solid var(--border);
  flex-shrink: 0;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s;
  margin-top: 2px;
  background: transparent;
  padding: 0;
}
.task-check:hover {
  border-color: var(--accent);
}
.task-check.checked {
  background: var(--accent);
  border-color: var(--accent);
}
.task-check.checked::after {
  content: "✓";
  font-size: 11px;
  color: #111;
  font-weight: 700;
}

.task-body {
  flex: 1;
}
.task-title {
  font-weight: 500;
  font-size: 0.95rem;
  margin-bottom: 6px;
}
.task-meta {
  display: flex;
  gap: 8px;
  align-items: center;
  flex-wrap: wrap;
}

.priority-badge {
  font-family: "Space Mono", monospace;
  font-size: 0.65rem;
  padding: 3px 8px;
  border-radius: 4px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-weight: 700;
}
.priority-high {
  background: rgba(255, 79, 79, 0.15);
  color: #ff4f4f;
}
.priority-medium {
  background: rgba(255, 180, 50, 0.15);
  color: #ffb432;
}
.priority-low {
  background: rgba(100, 200, 100, 0.15);
  color: #64c864;
}

.due-date {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-family: "Space Mono", monospace;
}
.due-date.overdue {
  color: var(--danger);
}

.task-del {
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  font-size: 1.1rem;
  padding: 2px 6px;
  border-radius: 4px;
  transition: all 0.2s;
  flex-shrink: 0;
}
.task-del:hover {
  color: var(--danger);
  background: rgba(255, 79, 79, 0.1);
}

.task-check:focus-visible,
.task-del:focus-visible,
.add-btn:focus-visible,
.filter-btn:focus-visible,
input:focus-visible,
select:focus-visible,
.toggle:focus-within {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.empty {
  text-align: center;
  padding: 60px 20px;
  color: var(--text-muted);
  font-family: "Space Mono", monospace;
  font-size: 0.85rem;
  border: 1px dashed var(--border);
  border-radius: 12px;
}
.empty-icon {
  font-size: 2.5rem;
  margin-bottom: 12px;
}

.section-title {
  font-family: "Space Mono", monospace;
  font-size: 1rem;
  margin-bottom: 14px;
}

.content-section {
  margin-top: 44px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 22px;
}

.content-section h2 {
  font-family: "Space Mono", monospace;
  font-size: 1.1rem;
  margin-bottom: 14px;
}

.content-section ul {
  padding-left: 18px;
  display: grid;
  gap: 10px;
  line-height: 1.5;
}

.content-section details {
  border-top: 1px solid var(--border);
  padding-top: 12px;
  margin-top: 12px;
}

.content-section details:first-of-type {
  border-top: none;
  padding-top: 0;
  margin-top: 0;
}

.content-section summary {
  cursor: pointer;
  font-weight: 700;
}

.content-section p {
  margin-top: 8px;
  color: var(--text-muted);
  line-height: 1.5;
}

.site-footer {
  padding: 24px;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.88rem;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

@media (max-width: 700px) {
  .site-header {
    padding: 20px 20px;
  }
  .site-nav {
    order: 3;
    width: 100%;
  }
}