/* ===========================
   CSS Custom Properties
   =========================== */
:root {
  --color-bg: #111111;
  --color-bg-secondary: #191919;
  --color-bg-tertiary: #212121;
  --color-border: #2A2A2A;
  --color-border-light: #383838;
  --color-text: #D8E4E0;
  --color-text-secondary: #666666;
  --color-text-muted: #444444;
  --color-primary: #0ea5e9;
  --color-primary-hover: #0284c7;
  --color-primary-light: rgba(14,165,233,0.12);
  --color-secondary: #eab308;
  --color-secondary-hover: #ca8a04;
  --color-note: #eab308;
  --color-note-hover: #ca8a04;
  --color-success: #0ea5e9;
  --color-danger: #c0635a;
  --color-danger-hover: #a8524a;
  --color-warning: #eab308;
  --color-link: #38bdf8;
  --color-link-hover: #7dd3fc;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.4);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.5);
  --shadow-lg: 0 8px 24px rgba(0,0,0,0.6);
  --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
  --sidebar-width: 280px;
}

/* ===========================
   Reset & Base
   =========================== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

body {
  font-family: var(--font-sans);
  background-color: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a {
  color: var(--color-link);
  text-decoration: none;
}

a:hover {
  color: var(--color-link-hover);
  text-decoration: underline;
}

code, pre {
  font-family: var(--font-mono);
  font-size: 0.875em;
}

code {
  background: var(--color-bg-tertiary);
  padding: 0.15em 0.4em;
  border-radius: var(--radius-sm);
  color: var(--color-primary);
}

.brand {
  display: inline-flex;
  text-decoration: none;
}

.brand:hover {
  text-decoration: none;
}

.brand-logo {
  height: 28px;
  width: auto;
  display: block;
}

/* ===========================
   Main Content
   =========================== */
.main-content {
  flex: 1;
}

/* ===========================
   Buttons
   =========================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  padding: 0.5rem 1rem;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  border: 1px solid transparent;
  transition: background-color 0.15s, color 0.15s, border-color 0.15s, opacity 0.15s;
  white-space: nowrap;
  text-decoration: none;
  line-height: 1.4;
}

.btn:hover {
  text-decoration: none;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.btn-primary {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
}

.btn-primary:hover {
  background: var(--color-primary-hover);
  border-color: var(--color-primary-hover);
  color: #fff;
}

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

.btn-secondary:hover {
  background: var(--color-secondary-hover);
  border-color: var(--color-secondary-hover);
  color: #fff;
}

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

.btn-ghost:hover {
  background: var(--color-bg-tertiary);
  color: var(--color-text);
  border-color: var(--color-border-light);
}

.btn-outline {
  background: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
}

.btn-outline:hover {
  background: var(--color-primary);
  color: #fff;
}

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

.btn-danger:hover {
  background: rgba(192,99,90,0.15);
  border-color: var(--color-danger);
}

.btn-icon {
  padding: 0.3rem 0.5rem;
  background: transparent;
  border-color: transparent;
  color: var(--color-text-secondary);
  font-size: 1rem;
}

.btn-icon:hover {
  background: var(--color-bg-tertiary);
  color: var(--color-text);
}

.btn-move {
  opacity: 0.4;
  font-size: 0.85rem;
}

.btn-move:hover {
  opacity: 1;
}

.btn-sm {
  padding: 0.3rem 0.7rem;
  font-size: 0.8rem;
}

.btn-lg {
  padding: 0.75rem 1.75rem;
  font-size: 1rem;
}

.btn-full {
  width: 100%;
}

.inline-form {
  display: inline;
}

/* ===========================
   Form Elements
   =========================== */
.form-group {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.form-label {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-secondary);
}

.form-optional {
  color: var(--color-text-muted);
  font-weight: 400;
}

.form-hint {
  color: var(--color-text-muted);
  font-size: 0.75rem;
  font-weight: 400;
}

.form-input,
.form-textarea {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  color: var(--color-text);
  font-family: var(--font-sans);
  font-size: 0.9rem;
  padding: 0.6rem 0.85rem;
  transition: border-color 0.15s;
  outline: none;
  width: 100%;
}

.form-input:focus,
.form-textarea:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(14,165,233,0.2);
}

.form-input::placeholder,
.form-textarea::placeholder {
  color: var(--color-text-muted);
}

.form-textarea {
  resize: vertical;
  min-height: 100px;
  line-height: 1.5;
}

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

/* ===========================
   Alert
   =========================== */
.alert {
  padding: 0.75rem 1rem;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  border: 1px solid transparent;
}

.alert-error {
  background: rgba(192,99,90,0.1);
  color: #d4928a;
  border-color: rgba(192,99,90,0.3);
}

.alert-success {
  background: rgba(14,165,233,0.1);
  color: var(--color-primary);
  border-color: rgba(14,165,233,0.3);
}

/* ===========================
   Auth Pages
   =========================== */
.auth-container {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: 2rem 1rem;
}

.auth-card {
  background: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 2.5rem;
  width: 100%;
  max-width: 420px;
  box-shadow: var(--shadow-lg);
}

.auth-title {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 0.4rem;
  letter-spacing: -0.02em;
}

.auth-subtitle {
  color: var(--color-text-secondary);
  margin-bottom: 2rem;
  font-size: 0.95rem;
}

.auth-form {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.auth-switch {
  margin-top: 1.5rem;
  text-align: center;
  color: var(--color-text-secondary);
  font-size: 0.875rem;
}

/* ===========================
   Landing Page
   =========================== */
.landing {
  max-width: 960px;
  margin: 0 auto;
  padding: 4rem 1.5rem;
}

.landing-hero {
  text-align: center;
  padding: 3rem 0 4rem;
}

.landing-logo {
  height: 64px;
  width: auto;
  margin: 0 auto 1rem;
  display: block;
}

.landing-tagline {
  font-size: 1.4rem;
  color: var(--color-text-secondary);
  margin-bottom: 1rem;
}

.landing-desc {
  font-size: 1rem;
  color: var(--color-text-secondary);
  max-width: 580px;
  margin: 0 auto 2.5rem;
  line-height: 1.7;
}

.landing-desc code {
  font-size: 0.9em;
}

.landing-actions {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

.landing-features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.5rem;
  margin-bottom: 4rem;
}

.feature-card {
  background: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 1.5rem;
}

.feature-icon {
  font-size: 2rem;
  margin-bottom: 0.75rem;
}

.feature-card h3 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.feature-card p {
  color: var(--color-text-secondary);
  font-size: 0.875rem;
  line-height: 1.6;
}

.landing-example {
  background: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 2rem;
}

.landing-example h2 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 1.25rem;
}

.example-paths {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

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

.example-path.child {
  padding-left: 1.5rem;
}

.example-path.child-2 {
  padding-left: 3rem;
}

.path-url {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  background: var(--color-bg-tertiary);
  padding: 0.3rem 0.75rem;
  border-radius: var(--radius-sm);
}

.path-url strong {
  color: var(--color-primary);
}

.path-desc {
  color: var(--color-text-muted);
  font-size: 0.85rem;
}

/* ===========================
   Path Layout
   =========================== */
.mobile-header {
  display: none;
}

.path-layout {
  display: flex;
  min-height: 100vh;
  margin: 0 auto;
  width: 100%;
}

/* ===========================
   Sidebar
   =========================== */
.sidebar {
  width: var(--sidebar-width);
  min-width: var(--sidebar-width);
  background: var(--color-bg-secondary);
  border-right: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  height: 100vh;
  display: flex;
  flex-direction: column;
}

.sidebar-brand {
  padding: 1.1rem 1rem;
  border-bottom: 1px solid var(--color-border);
  flex-shrink: 0;
}

.sidebar-nav {
  flex: 1;
  overflow-y: auto;
  padding: 0.75rem 0;
}

.sidebar-user {
  padding: 0.75rem 1rem;
  border-top: 1px solid var(--color-border);
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
}

.user-email {
  color: var(--color-text-secondary);
  font-size: 0.8rem;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  min-width: 0;
}

.sidebar-home {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 1rem;
  color: var(--color-text-secondary);
  font-size: 0.9rem;
  transition: background 0.1s;
  border-radius: 0;
}

.sidebar-home:hover {
  background: var(--color-bg-tertiary);
  color: var(--color-text);
  text-decoration: none;
}

.sidebar-home.active {
  color: var(--color-primary);
  background: var(--color-primary-light);
}

.sidebar-section {
  margin-top: 0.5rem;
}

.sidebar-section-title {
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  padding: 0.5rem 1rem 0.25rem;
}

.path-list {
  list-style: none;
}

.path-item {
  display: block;
}

.path-link {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 1rem;
  color: var(--color-text-secondary);
  font-size: 0.85rem;
  transition: background 0.1s;
}

.path-link:hover {
  background: var(--color-bg-tertiary);
  color: var(--color-text);
  text-decoration: none;
}

.path-link.active {
  color: var(--color-primary);
  background: var(--color-primary-light);
}

.path-icon {
  font-size: 0.85rem;
  flex-shrink: 0;
}

.path-name {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  font-family: var(--font-mono);
  font-size: 0.8rem;
}

/* ===========================
   Path Main Content
   =========================== */
.path-main {
  flex: 1;
  padding: 2rem;
  overflow-y: auto;
  min-width: 0;
}

.path-header {
  margin-bottom: 2rem;
}

.path-breadcrumb {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  font-size: 0.8rem;
  color: var(--color-text-muted);
  margin-bottom: 0.5rem;
  flex-wrap: wrap;
}

.breadcrumb-home {
  color: var(--color-text-muted);
}

.breadcrumb-home:hover {
  color: var(--color-text-secondary);
}

.breadcrumb-sep {
  color: var(--color-text-muted);
}

.breadcrumb-part {
  color: var(--color-text-secondary);
}

.breadcrumb-part:hover {
  color: var(--color-text);
}

.path-title {
  font-size: 1.75rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  word-break: break-all;
}

.path-prefix {
  color: var(--color-text-muted);
}

.path-hint {
  color: var(--color-text-secondary);
  margin-top: 0.75rem;
}

.home-paths {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 0.75rem;
  margin-top: 1.5rem;
}

.home-path-card {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1rem;
  background: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  color: var(--color-text);
  text-decoration: none;
  font-size: 0.9rem;
  transition: border-color 0.15s, background 0.15s;
}

.home-path-card:hover {
  background: var(--color-bg-tertiary);
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.home-path-name {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* ===========================
   Add Item
   =========================== */
.add-item-container {
  margin-bottom: 1.5rem;
}

.add-buttons {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.add-form-container {
  background: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 1.25rem;
}

.add-form {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

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

.form-title {
  font-size: 1rem;
  font-weight: 600;
}

/* ===========================
   Items List
   =========================== */
.items-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  margin-bottom: 2rem;
}

/* ===========================
   Item Card
   =========================== */
.item-card {
  background: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 1rem 1.25rem;
  transition: border-color 0.15s;
}

.item-card:hover {
  border-color: var(--color-border-light);
}

.item-card.item-editing {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(14,165,233,0.15);
}

.item-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 0.6rem;
}

.item-meta {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  flex-wrap: wrap;
  min-width: 0;
}

.item-type-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  padding: 0.2rem 0.5rem;
  border-radius: 100px;
  flex-shrink: 0;
}

.item-type-link {
  background: rgba(56,189,248,0.12);
  color: var(--color-link);
}

.item-type-note {
  background: rgba(234,179,8,0.12);
  color: var(--color-note);
}

.item-title {
  font-weight: 500;
  font-size: 0.95rem;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.item-actions {
  display: flex;
  gap: 0.25rem;
  flex-shrink: 0;
  opacity: 0;
  transition: opacity 0.15s;
}

.item-card:hover .item-actions {
  opacity: 1;
}

.item-content {
  min-width: 0;
}

.item-card.item-link {
  padding: 0.5rem 1.25rem;
}

.item-link-row {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  min-width: 0;
}

.item-link-text {
  color: var(--color-link);
  font-size: 0.875rem;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  flex: 1;
  min-width: 0;
}

.item-link-text:hover {
  color: var(--color-link-hover);
}

.item-url {
  color: var(--color-link);
  font-size: 0.875rem;
  word-break: break-all;
  display: block;
}

.item-url:hover {
  color: var(--color-link-hover);
}

.item-body {
  color: var(--color-text-secondary);
  font-size: 0.9rem;
}

.edit-form {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.form-actions-inline {
  display: flex;
  gap: 0.4rem;
}

/* ===========================
   Ancestors Section
   =========================== */
.ancestors-section {
  margin-top: 2.5rem;
  border-top: 1px solid var(--color-border);
  padding-top: 2rem;
}

.ancestors-heading {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  margin-bottom: 1.25rem;
}

.ancestor-group {
  margin-bottom: 1rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.ancestor-summary {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.75rem 1rem;
  cursor: pointer;
  list-style: none;
  background: var(--color-bg-secondary);
  user-select: none;
}

.ancestor-summary::-webkit-details-marker {
  display: none;
}

.ancestor-summary::before {
  content: '▶';
  font-size: 0.65rem;
  color: var(--color-text-muted);
  transition: transform 0.15s;
  flex-shrink: 0;
}

details[open] .ancestor-summary::before {
  transform: rotate(90deg);
}

.ancestor-path {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--color-text-secondary);
}

.ancestor-path:hover {
  color: var(--color-text);
}

.ancestor-count {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  margin-left: auto;
}

.ancestor-items {
  padding: 0.75rem;
  background: var(--color-bg);
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.ancestor-items .item-actions {
  display: none;
}

/* ===========================
   Markdown Body
   =========================== */
.markdown-body {
  color: var(--color-text-secondary);
  font-size: 0.9rem;
  line-height: 1.7;
}

.markdown-body h1,
.markdown-body h2,
.markdown-body h3,
.markdown-body h4,
.markdown-body h5,
.markdown-body h6 {
  color: var(--color-text);
  margin: 1em 0 0.5em;
  font-weight: 600;
  line-height: 1.3;
}

.markdown-body h1 { font-size: 1.4em; }
.markdown-body h2 { font-size: 1.2em; }
.markdown-body h3 { font-size: 1.05em; }

.markdown-body p {
  margin-bottom: 0.75em;
}

.markdown-body p:last-child {
  margin-bottom: 0;
}

.markdown-body a {
  color: var(--color-link);
}

.markdown-body a:hover {
  color: var(--color-link-hover);
}

.markdown-body ul,
.markdown-body ol {
  padding-left: 1.5em;
  margin-bottom: 0.75em;
}

.markdown-body li {
  margin-bottom: 0.25em;
}

.markdown-body blockquote {
  border-left: 3px solid var(--color-border-light);
  padding-left: 1em;
  margin: 0.75em 0;
  color: var(--color-text-muted);
  font-style: italic;
}

.markdown-body pre {
  background: var(--color-bg-tertiary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 0.75em 1em;
  overflow-x: auto;
  margin: 0.75em 0;
}

.markdown-body pre code {
  background: none;
  padding: 0;
  color: var(--color-text);
}

.markdown-body code {
  background: var(--color-bg-tertiary);
  padding: 0.15em 0.4em;
  border-radius: var(--radius-sm);
  color: var(--color-link);
  font-size: 0.875em;
}

.markdown-body hr {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: 1em 0;
}

.markdown-body table {
  border-collapse: collapse;
  width: 100%;
  margin: 0.75em 0;
  font-size: 0.875em;
}

.markdown-body th,
.markdown-body td {
  border: 1px solid var(--color-border);
  padding: 0.4em 0.75em;
  text-align: left;
}

.markdown-body th {
  background: var(--color-bg-tertiary);
  font-weight: 600;
  color: var(--color-text);
}

/* ===========================
   Responsive
   =========================== */
@media (max-width: 768px) {
  .mobile-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 1rem;
    height: 52px;
    background: var(--color-bg-secondary);
    border-bottom: 1px solid var(--color-border);
    position: sticky;
    top: 0;
    z-index: 100;
  }

  .path-layout {
    flex-direction: column;
  }

  .sidebar {
    width: 100%;
    min-width: 100%;
    height: auto;
    position: static;
    border-right: none;
    border-bottom: 1px solid var(--color-border);
  }

  .sidebar-brand,
  .sidebar-user {
    display: none;
  }

  .path-main {
    padding: 1.25rem;
  }

  .auth-card {
    padding: 1.75rem;
  }
}

@media (max-width: 480px) {
  .landing {
    padding: 2rem 1rem;
  }

  .example-path {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.25rem;
  }

  .example-path.child,
  .example-path.child-2 {
    padding-left: 0.75rem;
    border-left: 2px solid var(--color-border);
  }

  .add-buttons {
    flex-direction: column;
  }

  .add-buttons .btn {
    width: 100%;
  }
}