:root {
  --bg: #f4f5f7;
  --panel: #ffffff;
  --ink: #1f2933;
  --muted: #6b7280;
  --border: #d9dde3;
  --accent: #2f6fed;
  --accent-ink: #ffffff;
  --danger: #d64545;
  --to-read: #b45309;
  --reading: #1d4ed8;
  --done: #15803d;
  --shadow: 0 1px 3px rgba(15, 23, 42, 0.08);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.5;
}

.topbar {
  padding: 1.75rem 1.5rem 1.25rem;
  background: var(--panel);
  border-bottom: 1px solid var(--border);
}

.topbar h1 {
  margin: 0;
  font-size: 1.6rem;
}

.subtitle {
  margin: 0.25rem 0 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.container {
  max-width: 960px;
  margin: 1.5rem auto;
  padding: 0 1.5rem;
  display: grid;
  grid-template-columns: 340px 1fr;
  gap: 1.5rem;
  align-items: start;
}

@media (max-width: 760px) {
  .container {
    grid-template-columns: 1fr;
  }
}

.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1.25rem;
  box-shadow: var(--shadow);
}

.panel h2 {
  margin-top: 0;
  font-size: 1.15rem;
}

form label {
  display: block;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--muted);
  margin: 0.75rem 0 0.25rem;
}

input[type="text"],
select {
  width: 100%;
  padding: 0.5rem 0.6rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 0.95rem;
  background: #fff;
  color: var(--ink);
}

input[type="text"]:focus,
select:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 2px rgba(47, 111, 237, 0.15);
}

.row {
  display: flex;
  gap: 0.75rem;
}

.row .field {
  flex: 1;
}

.form-actions {
  margin-top: 1.1rem;
  display: flex;
  gap: 0.5rem;
}

button {
  font: inherit;
  cursor: pointer;
  border-radius: 6px;
  border: 1px solid transparent;
  padding: 0.5rem 0.9rem;
}

button.primary {
  background: var(--accent);
  color: var(--accent-ink);
}

button.primary:hover {
  background: #235bd0;
}

button.secondary {
  background: #fff;
  border-color: var(--border);
  color: var(--ink);
}

button.secondary:hover {
  background: #f0f2f5;
}

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

.filter {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.filter label {
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--muted);
}

.filter select {
  width: auto;
}

.book-list {
  list-style: none;
  margin: 1rem 0 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.book-item {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.85rem 1rem;
}

.book-main {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  align-items: flex-start;
}

.book-title {
  margin: 0;
  font-size: 1.02rem;
}

.book-author {
  margin: 0.1rem 0 0;
  color: var(--muted);
  font-size: 0.9rem;
}

.book-meta {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-top: 0.6rem;
  flex-wrap: wrap;
}

.badge {
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.15rem 0.55rem;
  border-radius: 999px;
  text-transform: uppercase;
  letter-spacing: 0.02em;
  color: #fff;
}

.badge.to-read {
  background: var(--to-read);
}

.badge.reading {
  background: var(--reading);
}

.badge.done {
  background: var(--done);
}

.rating {
  font-size: 0.85rem;
  color: #b7791f;
  font-weight: 600;
}

.tags {
  display: flex;
  gap: 0.35rem;
  flex-wrap: wrap;
}

.tag {
  font-size: 0.75rem;
  background: #eef1f6;
  color: #3b4453;
  padding: 0.1rem 0.45rem;
  border-radius: 4px;
}

.book-actions {
  display: flex;
  gap: 0.4rem;
  flex-shrink: 0;
}

.book-actions button {
  padding: 0.3rem 0.6rem;
  font-size: 0.82rem;
}

button.link-danger {
  background: #fff;
  border-color: var(--border);
  color: var(--danger);
}

button.link-danger:hover {
  background: #fdecec;
  border-color: var(--danger);
}

.muted {
  color: var(--muted);
  font-size: 0.9rem;
}

.error {
  color: var(--danger);
  font-size: 0.88rem;
  margin: 0.6rem 0 0;
}

.hidden {
  display: none !important;
}