*,
*::before,
*::after {
  box-sizing: border-box;
}

:root {
  --bg: #f4f6f8;
  --surface: #ffffff;
  --text: #1a1d21;
  --muted: #5c6570;
  --border: #d8dee6;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --danger: #b91c1c;
  --danger-bg: #fef2f2;
  --danger-border: #fecaca;
  --radius: 10px;
  --shadow: 0 1px 2px rgba(16, 24, 40, 0.06), 0 4px 12px rgba(16, 24, 40, 0.04);
  --font: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.5;
  color: var(--text);
  background: var(--bg);
}

.app {
  width: min(100% - 2rem, 40rem);
  margin: 0 auto;
  padding: 1.5rem 0 3rem;
}

.header {
  margin-bottom: 1.25rem;
}

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

.header h1 {
  margin: 0;
  font-size: 1.75rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.subtitle {
  margin: 0.35rem 0 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.btn-auth {
  flex-shrink: 0;
  font: inherit;
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  border-radius: 8px;
  border: 1px solid var(--border);
  padding: 0.55rem 0.9rem;
  color: #fff;
  background: var(--accent);
}

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

.btn-auth.is-logout {
  color: var(--text);
  background: var(--surface);
}

.btn-auth.is-logout:hover {
  border-color: var(--accent);
  background: #eff6ff;
}

.error-banner {
  margin-bottom: 1rem;
  padding: 0.75rem 1rem;
  border: 1px solid var(--danger-border);
  border-radius: var(--radius);
  background: var(--danger-bg);
  color: var(--danger);
  font-size: 0.95rem;
}

.create-section,
.list-section {
  margin-bottom: 1.75rem;
}

.create-section h2,
.list-section h2 {
  margin: 0 0 0.75rem;
  font-size: 1.05rem;
  font-weight: 600;
}

.note-form {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
  padding: 1rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.note-form label {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--muted);
}

.note-form input,
.note-form textarea {
  width: 100%;
  padding: 0.65rem 0.75rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  font: inherit;
  color: var(--text);
  background: #fff;
  resize: vertical;
}

.note-form input:focus,
.note-form textarea:focus {
  outline: 2px solid color-mix(in srgb, var(--accent) 45%, transparent);
  outline-offset: 1px;
  border-color: var(--accent);
}

.note-form button[type="submit"],
.card-actions button {
  font: inherit;
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  border-radius: 8px;
  border: 1px solid transparent;
  padding: 0.55rem 0.9rem;
}

.note-form button[type="submit"] {
  align-self: flex-start;
  color: #fff;
  background: var(--accent);
}

.note-form button[type="submit"]:hover:not(:disabled) {
  background: var(--accent-hover);
}

.note-form button[type="submit"]:disabled,
.card-actions button:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

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

.status.empty {
  padding: 1.25rem 1rem;
  text-align: center;
  border: 1px dashed var(--border);
  border-radius: var(--radius);
  background: var(--surface);
}

.notes-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.note-card {
  padding: 1rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.note-card .note-title {
  margin: 0 0 0.4rem;
  font-size: 1.05rem;
  font-weight: 650;
  word-break: break-word;
}

.note-card .note-content {
  margin: 0 0 0.65rem;
  color: var(--text);
  white-space: pre-wrap;
  word-break: break-word;
}

.note-card .note-meta {
  margin: 0 0 0.85rem;
  font-size: 0.8rem;
  color: var(--muted);
}

.card-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.card-actions .btn-edit,
.card-actions .btn-save {
  color: var(--accent);
  background: transparent;
  border-color: var(--border);
}

.card-actions .btn-edit:hover:not(:disabled),
.card-actions .btn-save:hover:not(:disabled) {
  border-color: var(--accent);
  background: #eff6ff;
}

.card-actions .btn-cancel {
  color: var(--muted);
  background: transparent;
  border-color: var(--border);
}

.card-actions .btn-delete {
  color: var(--danger);
  background: transparent;
  border-color: var(--danger-border);
}

.card-actions .btn-delete:hover:not(:disabled) {
  background: var(--danger-bg);
}

.note-card.is-editing .note-form {
  box-shadow: none;
  padding: 0;
  border: none;
  margin-bottom: 0.75rem;
}

@media (min-width: 640px) {
  .app {
    padding-top: 2.25rem;
  }

  .header h1 {
    font-size: 2rem;
  }
}