/* --- Variables --- */
:root {
  --bg: #111113;
  --bg-panel: #18181b;
  --bg-elevated: #1f1f23;
  --bg-input: #1f1f23;
  --border: #27272a;
  --border-focus: #3f3f46;
  --text: #fafafa;
  --text-muted: #d4d4d8;
  --text-dim: #b8b8c0;
  --accent: #f59e0b;
  --accent-hover: #fbbf24;
  --accent-muted: rgba(245, 158, 11, 0.2);
  --error: #f87171;
  --font-sans: 'Plus Jakarta Sans', system-ui, -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', 'Consolas', monospace;
  --space: 1rem;
  --space-sm: 0.5rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --radius: 8px;
  --radius-lg: 12px;
  --radius-full: 9999px;
  --ease: 0.2s ease;
  --content-max: 1600px;
  /* Command colors (hint, input, log): visible but not harsh */
  --cmd-mount: #a78bfa;
  --cmd-mkdir: #34d399;
  --cmd-create: #22d3ee;
  --cmd-ls: #eab308;
  --cmd-cd: #f472b6;
  --cmd-read: #60a5fa;
  --cmd-write: #4ade80;
  --cmd-delete: #fb923c;
  --cmd-resize: #c084fc;
  --cmd-defrag: #2dd4bf;
  --cmd-buffer: #94a3b8;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-mono);
  font-size: 14px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

/* --- Hero --- */
.hero {
  padding: var(--space-lg) var(--space-lg) var(--space-xl);
  max-width: var(--content-max);
  margin: 0 auto;
}

.hero-title {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 1.6rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--text);
}

.hero-title-accent {
  color: var(--accent);
  font-weight: 600;
}

.hero-intro {
  margin: var(--space-sm) 0 0 0;
  font-size: 0.9rem;
  color: var(--text-muted);
  font-family: var(--font-sans);
  font-weight: 500;
}

/* --- Main grid --- */
.main {
  max-width: var(--content-max);
  margin: 0 auto;
  padding: 0 var(--space-lg) var(--space-xl);
  display: grid;
  grid-template-columns: 1fr 1fr;
  grid-template-rows: minmax(0, 1fr);
  gap: var(--space-xl);
  align-items: stretch;
  height: 65vh;
  min-height: 420px;
}

@media (max-width: 640px) {
  .main {
    grid-template-columns: 1fr;
    grid-template-rows: minmax(0, 1fr) minmax(0, 1fr);
    height: 78vh;
    min-height: 480px;
  }
}

/* --- Controls --- */
.controls-panel {
  background: var(--bg-panel);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  display: flex;
  flex-direction: column;
  gap: var(--space);
  min-height: 0;
}

.controls-header {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.controls-label {
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text);
  margin: 0;
}

.controls-hint {
  font-size: 0.75rem;
  color: var(--text-dim);
  letter-spacing: 0.01em;
}

.controls-hint .cmd-hint-mount {
  color: var(--cmd-mount);
}
.controls-hint .cmd-hint-mkdir {
  color: var(--cmd-mkdir);
}
.controls-hint .cmd-hint-create {
  color: var(--cmd-create);
}
.controls-hint .cmd-hint-ls {
  color: var(--cmd-ls);
}
.controls-hint .cmd-hint-cd {
  color: var(--cmd-cd);
}
.controls-hint .cmd-hint-read {
  color: var(--cmd-read);
}
.controls-hint .cmd-hint-write {
  color: var(--cmd-write);
}
.controls-hint .cmd-hint-delete {
  color: var(--cmd-delete);
}
.controls-hint .cmd-hint-resize {
  color: var(--cmd-resize);
}
.controls-hint .cmd-hint-defrag {
  color: var(--cmd-defrag);
}

.cmd-input-wrap {
  position: relative;
  flex: 1;
  min-height: 100px;
  display: flex;
}

.cmd-input-highlight {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  padding: var(--space);
  overflow: auto;
  pointer-events: none;
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.6;
  white-space: pre-wrap;
  word-wrap: break-word;
  background: var(--bg-input);
  border: 1px solid transparent;
  border-radius: var(--radius);
  color: var(--text);
}

.cmd-input-highlight .cmd-input-line {
  min-height: 1.6em;
}

.cmd-input-highlight .cmd-input-mount {
  color: var(--cmd-mount);
}
.cmd-input-highlight .cmd-input-mkdir {
  color: var(--cmd-mkdir);
}
.cmd-input-highlight .cmd-input-create {
  color: var(--cmd-create);
}
.cmd-input-highlight .cmd-input-ls {
  color: var(--cmd-ls);
}
.cmd-input-highlight .cmd-input-cd {
  color: var(--cmd-cd);
}
.cmd-input-highlight .cmd-input-read {
  color: var(--cmd-read);
}
.cmd-input-highlight .cmd-input-write {
  color: var(--cmd-write);
}
.cmd-input-highlight .cmd-input-delete {
  color: var(--cmd-delete);
}
.cmd-input-highlight .cmd-input-resize {
  color: var(--cmd-resize);
}
.cmd-input-highlight .cmd-input-defrag {
  color: var(--cmd-defrag);
}
.cmd-input-highlight .cmd-input-buffer {
  color: var(--cmd-buffer);
}

#cmd-input {
  position: relative;
  z-index: 1;
  width: 100%;
  padding: var(--space);
  background: transparent;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: transparent;
  caret-color: var(--text);
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.6;
  resize: vertical;
  min-height: 100px;
  display: block;
  transition:
    border-color var(--ease),
    box-shadow var(--ease);
}

#cmd-input::placeholder {
  color: var(--text-dim);
}

#cmd-input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-muted);
}

.controls-actions {
  display: flex;
  justify-content: flex-end;
  gap: var(--space-sm);
  flex-wrap: wrap;
  padding-top: var(--space-sm);
  border-top: 1px solid var(--border);
}

.btn {
  padding: 0.5rem 1.25rem;
  border-radius: var(--radius);
  font-family: var(--font-sans);
  font-size: 0.875rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition:
    background var(--ease),
    color var(--ease),
    opacity var(--ease),
    transform var(--ease);
  min-height: 36px;
}

.btn-primary {
  background: var(--accent);
  color: #0c0c0d;
}

.btn-primary:hover:not(:disabled) {
  background: var(--accent-hover);
  transform: translateY(-1px);
}

.btn-primary:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  transform: none;
}

.btn-primary.loading {
  position: relative;
  color: transparent;
}

.btn-primary.loading::after {
  content: '';
  position: absolute;
  inset: 0;
  margin: auto;
  width: 1em;
  height: 1em;
  border: 2px solid #0c0c0d;
  border-top-color: transparent;
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

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

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

.samples {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-top: var(--space);
}

.btn-sample {
  background: var(--bg-elevated);
  color: var(--text-muted);
  border: 1px solid var(--border);
  padding: 0.4rem 0.85rem;
  font-size: 0.8rem;
  font-weight: 500;
  border-radius: var(--radius-full);
  font-family: var(--font-sans);
}

.btn-sample:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-muted);
}

/* --- Results --- */
.results-panel {
  background: var(--bg-panel);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  min-height: 0;
  display: flex;
  flex-direction: column;
  min-width: 0;
  overflow: hidden;
}

.tabs-wrap {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-height: 0;
  overflow: hidden;
}

.tabs {
  display: flex;
  gap: var(--space-sm);
  margin-bottom: var(--space);
  flex-shrink: 0;
}

.tab {
  padding: 0.45rem 1rem;
  background: transparent;
  border: none;
  border-radius: var(--radius);
  color: var(--text-muted);
  font-family: var(--font-sans);
  font-size: 0.85rem;
  font-weight: 500;
  cursor: pointer;
  transition:
    color var(--ease),
    background var(--ease);
}

.tab:hover {
  color: var(--text);
  background: var(--bg-elevated);
}

.tab.active {
  color: var(--accent);
  background: var(--accent-muted);
}

.tab-panel {
  display: none;
  flex: 1;
  min-height: 0;
  overflow: hidden;
  flex-direction: column;
}

.tab-panel.active {
  display: flex;
  animation: fadeIn 0.2s ease;
}

@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

.tab-panel[hidden] {
  display: none !important;
}

.tab-panel-body {
  flex: 1;
  min-height: 0;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.tab-panel-body > .empty-state {
  flex: 1 1 0%;
  min-height: 0;
  align-self: stretch;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
}

.tab-panel-body > [data-content][hidden] {
  flex: none;
  display: none !important;
}

.empty-state {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: var(--space-xl);
  min-height: 0;
  font-family: var(--font-sans);
}

.empty-state-icon {
  font-size: 2rem;
  line-height: 1;
  margin-bottom: var(--space);
  opacity: 0.6;
}

.empty-state-title {
  margin: 0 0 var(--space-sm) 0;
  font-size: 1rem;
  font-weight: 600;
  color: var(--text);
}

.empty-state-hint {
  margin: 0;
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.5;
  max-width: 20em;
}

.empty-state[hidden] {
  display: none;
}

.tree-view,
.inodes-view,
.blocks-view {
  padding: var(--space-sm) 0;
  flex: 1;
  min-height: 0;
  overflow: auto;
}

.log-caption {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin: 0 0 var(--space) 0;
  line-height: 1.5;
  flex-shrink: 0;
  font-family: var(--font-sans);
}

.log-caption[hidden] {
  display: none;
}

.log-caption code {
  background: var(--bg-elevated);
  padding: 0.15em 0.4em;
  border-radius: 4px;
  font-size: 0.85em;
}

.log-view {
  flex: 1;
  min-height: 0;
  overflow: auto;
  padding: var(--space-sm) 0;
  font-size: 12px;
  font-family: var(--font-mono);
  line-height: 1.6;
}

.log-line {
  padding: 0.3em 0;
  white-space: pre-wrap;
  word-break: break-word;
}

.log-line.log-cmd {
  color: var(--text-muted);
}

.log-view .log-line .log-cmd-mount {
  color: var(--cmd-mount) !important;
}
.log-view .log-line .log-cmd-mkdir {
  color: var(--cmd-mkdir) !important;
}
.log-view .log-line .log-cmd-create {
  color: var(--cmd-create) !important;
}
.log-view .log-line .log-cmd-ls {
  color: var(--cmd-ls) !important;
}
.log-view .log-line .log-cmd-cd {
  color: var(--cmd-cd) !important;
}
.log-view .log-line .log-cmd-read {
  color: var(--cmd-read) !important;
}
.log-view .log-line .log-cmd-write {
  color: var(--cmd-write) !important;
}
.log-view .log-line .log-cmd-delete {
  color: var(--cmd-delete) !important;
}
.log-view .log-line .log-cmd-resize {
  color: var(--cmd-resize) !important;
}
.log-view .log-line .log-cmd-defrag {
  color: var(--cmd-defrag) !important;
}
.log-view .log-line .log-cmd-buffer {
  color: var(--cmd-buffer) !important;
}

.log-line.log-err {
  color: var(--error);
  font-weight: 500;
}

.log-line.log-out {
  color: var(--text);
}

/* --- Tree --- */
.tree-view {
  font-size: 13px;
}

.tree-root {
  padding: 0;
}

.tree-root > .tree-item {
  font-weight: 600;
  padding: 0.5rem 0.6rem;
  border-radius: var(--radius);
  margin-bottom: 0.25rem;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
}

.tree-list {
  list-style: none;
  margin: 0;
  padding-left: 1.25rem;
  margin-left: 0.5rem;
  border-left: 1px solid var(--border);
  position: relative;
}

.tree-entry {
  margin: 0;
  padding: 0;
  position: relative;
}

.tree-entry::before {
  content: '';
  position: absolute;
  left: -1.25rem;
  top: 0.75em;
  width: 1.25rem;
  height: 0;
  border-top: 1px solid var(--border);
}

.tree-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 0.6rem;
  margin: 0.15rem 0;
  border-radius: var(--radius);
  transition: background var(--ease);
}

.tree-item:hover {
  background: var(--accent-muted);
}

.tree-icon {
  flex-shrink: 0;
  width: 1.1em;
  text-align: center;
  font-size: 1em;
  opacity: 0.9;
}

.tree-item.tree-dir .tree-icon::before {
  content: '📁';
}

.tree-item.tree-file .tree-icon::before {
  content: '📄';
}

.tree-name {
  font-family: var(--font-mono);
  font-weight: 500;
  min-width: 0;
}

.tree-item.tree-dir .tree-name {
  color: var(--accent);
}

.tree-item.tree-file .tree-name {
  color: var(--text);
}

.tree-meta {
  color: var(--text-muted);
  font-size: 0.8rem;
  font-family: var(--font-mono);
  margin-left: auto;
}

.tree-item.tree-dir .tree-meta {
  color: var(--text-dim);
}

/* --- Inodes --- */
.inodes-view table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
}

.inodes-view th,
.inodes-view td {
  padding: 0.5rem var(--space);
  text-align: left;
  border-bottom: 1px solid var(--border);
}

.inodes-view th {
  color: var(--text-muted);
  font-weight: 600;
  font-size: 0.75rem;
  font-family: var(--font-sans);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.inodes-view tr:hover td {
  background: var(--accent-muted);
}

/* --- Blocks --- */
.blocks-view {
  display: flex;
  flex-direction: column;
  min-height: 0;
  padding-left: 0.6rem;
  padding-right: 0.6rem;
}

.blocks-legend {
  display: flex;
  align-items: center;
  gap: var(--space);
  flex-wrap: wrap;
  margin-bottom: var(--space);
  font-size: 0.8rem;
  color: var(--text-muted);
  font-family: var(--font-sans);
}

.blocks-legend-title {
  font-weight: 600;
  margin-right: 0.25rem;
}

.blocks-legend-free i,
.blocks-legend-used i {
  display: inline-block;
  width: 0.75rem;
  height: 0.75rem;
  border-radius: 3px;
  margin-right: 0.35rem;
  vertical-align: middle;
}

.blocks-legend-free i {
  background: var(--border);
}

.blocks-legend-used i {
  background: var(--accent);
}

.blocks-view .blocks-grid {
  display: grid;
  grid-template-columns: repeat(13, minmax(0, 1fr));
  grid-auto-rows: minmax(24px, 1fr);
  gap: 6px;
  flex: 1;
  min-height: 200px;
}

.blocks-view .block-cell {
  border-radius: 6px;
  background: var(--border);
  transition:
    background var(--ease),
    transform var(--ease);
  min-height: 24px;
}

.blocks-view .block-cell:hover {
  transform: scale(1.06);
}

.blocks-view .block-cell.used {
  background: var(--accent);
}

.blocks-view .block-cell.used:hover {
  filter: brightness(1.15);
}

/* --- How it works --- */
.how-it-works {
  max-width: var(--content-max);
  margin: 0 auto;
  padding: var(--space-xl) var(--space-lg);
  border-top: 1px solid var(--border);
}

.how-it-works details {
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  background: var(--bg-panel);
}

.how-it-works summary {
  padding: var(--space) var(--space-lg);
  cursor: pointer;
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--text);
  user-select: none;
  transition: background var(--ease);
}

.how-it-works summary:hover {
  background: var(--bg-elevated);
}

.how-intro {
  padding: var(--space) var(--space-lg);
  margin: 0;
  color: var(--text-muted);
  font-size: 0.9rem;
  font-family: var(--font-sans);
}

.timeline {
  list-style: none;
  margin: 0;
  padding: var(--space-lg);
  padding-left: var(--space-xl);
  border-left: 2px solid var(--border);
  margin-left: var(--space);
}

.timeline-step {
  position: relative;
  padding: var(--space) 0;
  padding-left: var(--space);
}

.timeline-step::before {
  content: '';
  position: absolute;
  left: calc(-1 * var(--space-xl) - 5px);
  top: 1.35em;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--accent);
}

.timeline-step strong {
  font-weight: 600;
}

.timeline-step > strong:first-child {
  display: block;
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 600;
  color: var(--accent);
  letter-spacing: 0.01em;
  margin-bottom: 0.5em;
  padding-bottom: 0.25em;
  border-bottom: 1px solid var(--border);
}

.timeline-step code {
  background: var(--bg-elevated);
  padding: 0.15em 0.4em;
  border-radius: 4px;
  font-size: 0.88em;
}

/* --- FAB group (LinkedIn, GitHub, About) --- */
.fab-group {
  position: fixed;
  bottom: calc(var(--space-lg) + 2.25rem + 0.5rem);
  right: var(--space-lg);
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  z-index: 10;
}

.fab-link {
  width: 2.25rem;
  height: 2.25rem;
  padding: 0;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: var(--bg-panel);
  color: var(--text-muted);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition:
    color var(--ease),
    border-color var(--ease),
    background var(--ease);
}

.fab-link-linkedin:hover {
  color: #0a66c2;
  border-color: #0a66c2;
  background: rgba(10, 102, 194, 0.2);
}

.fab-link-github:hover {
  color: #3fb950;
  border-color: #3fb950;
  background: rgba(63, 185, 80, 0.2);
}

.fab-icon {
  width: 1.2rem;
  height: 1.2rem;
}

.about-fab {
  position: fixed;
  bottom: var(--space-lg);
  right: var(--space-lg);
  width: 2.25rem;
  height: 2.25rem;
  padding: 0;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: var(--bg-panel);
  color: var(--text-muted);
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 700;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition:
    color var(--ease),
    border-color var(--ease),
    background var(--ease);
  z-index: 10;
}

.about-fab:hover {
  color: var(--accent);
  border-color: var(--accent);
  background: var(--accent-muted);
}

/* --- About dialog --- */
.about-dialog {
  background: var(--bg-panel);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  color: var(--text);
  max-width: 440px;
}

.about-dialog::backdrop {
  background: rgba(0, 0, 0, 0.6);
}

.about-dialog h2 {
  margin: 0 0 var(--space) 0;
  font-size: 1.25rem;
  font-family: var(--font-sans);
  font-weight: 700;
}

.about-dialog p {
  margin: 0 0 var(--space) 0;
  color: var(--text-muted);
  font-size: 0.9rem;
  line-height: 1.65;
  font-family: var(--font-sans);
}

.about-dialog form {
  margin-top: var(--space);
}

/* --- Tree stagger --- */
.tree-view .tree-item.stagger {
  animation: staggerIn 0.2s ease backwards;
}

.tree-view .tree-entry:nth-child(1) .tree-item.stagger {
  animation-delay: 0.02s;
}
.tree-view .tree-entry:nth-child(2) .tree-item.stagger {
  animation-delay: 0.04s;
}
.tree-view .tree-entry:nth-child(3) .tree-item.stagger {
  animation-delay: 0.06s;
}
.tree-view .tree-entry:nth-child(4) .tree-item.stagger {
  animation-delay: 0.08s;
}
.tree-view .tree-entry:nth-child(5) .tree-item.stagger {
  animation-delay: 0.1s;
}
.tree-view .tree-entry:nth-child(n + 6) .tree-item.stagger {
  animation-delay: 0.12s;
}

@keyframes staggerIn {
  from {
    opacity: 0;
    transform: translateY(-4px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}