:root {
  color-scheme: light;
  scrollbar-gutter: stable;
  /* Bit colors */
  --sign: #64748b; /* Gray */
  --time: #3b82f6; /* Blue */
  --worker: #10b981; /* Green */
  --seq: #f59e0b; /* Yellow */

  /* Light theme variables (default) */
  --page-bg: #e2e8f0;
  --card-bg: #ffffff;
  --text: #0f172a;
  --text-muted: #64748b;
  --text-title: #1e293b;
  --label-color: #475569;
  --input-bg: #ffffff;
  --input-border: #cbd5e1;
  --vis-bg: #f1f5f9;
  --panel-bg: #f8fafc;
  --panel-border: #cbd5e1;
  --card-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  
  /* Theme switcher variables */
  --switcher-bg: #f1f5f9;
  --switcher-border: #e2e8f0;
  --switcher-btn-color: #64748b;
  --switcher-btn-hover: #1e293b;
  --switcher-btn-active-bg: #ffffff;
  --switcher-btn-active-color: #0f172a;
  --switcher-btn-active-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

[data-theme="dark"] {
  color-scheme: dark;
  --page-bg: #0b0f19;
  --card-bg: #151d2e;
  --text: #f8fafc;
  --text-muted: #94a3b8;
  --text-title: #f1f5f9;
  --label-color: #cbd5e1;
  --input-bg: #0f172a;
  --input-border: #334155;
  --vis-bg: #0f172a;
  --panel-bg: #0f172a;
  --panel-border: #334155;
  --card-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.5), 0 8px 10px -6px rgba(0, 0, 0, 0.4);
  
  /* Theme switcher variables */
  --switcher-bg: #0f172a;
  --switcher-border: #1e293b;
  --switcher-btn-color: #94a3b8;
  --switcher-btn-hover: #f1f5f9;
  --switcher-btn-active-bg: #1e293b;
  --switcher-btn-active-color: #38bdf8;
  --switcher-btn-active-shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
}

* {
  box-sizing: border-box;
}

body { 
  font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif; 
  background-color: var(--page-bg); 
  color: var(--text); 
  padding: 20px; 
  margin: 0; 
  display: flex; 
  flex-direction: column;
  justify-content: center; 
  align-items: center; 
  min-height: 100vh; 
  transition: background-color 0.25s ease, color 0.25s ease;
}

.card { 
  position: relative;
  background: var(--card-bg); 
  padding: 2.5rem 2rem 2rem 2rem; 
  border-radius: 12px; 
  box-shadow: var(--card-shadow); 
  width: min(840px, 100%);
  max-width: 840px; 
  transition: background-color 0.25s ease, box-shadow 0.25s ease;
}

.header {
  text-align: center;
  margin-bottom: 2rem;
}

.header-info {
  text-align: center;
}

h1 { 
  margin-top: 0; 
  margin-bottom: 0.5rem;
  color: var(--text-title); 
}

p.subtitle { 
  color: var(--text-muted); 
  margin: 0;
}

.header-actions {
  position: absolute;
  top: 1.5rem;
  right: 1.5rem;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  z-index: 20;
}

.github-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 6px;
  background: var(--switcher-bg);
  border: 1px solid var(--switcher-border);
  border-radius: 8px;
  color: var(--switcher-btn-color);
  text-decoration: none;
  transition: all 0.2s ease;
}

.github-link:hover {
  color: var(--switcher-btn-hover);
  border-color: var(--switcher-border);
  background: var(--switcher-btn-active-bg);
  box-shadow: var(--switcher-btn-active-shadow);
}

.theme-switcher {
  display: inline-flex;
  align-items: center;
  background: var(--switcher-bg);
  border: 1px solid var(--switcher-border);
  border-radius: 8px;
  padding: 3px;
  gap: 2px;
}

.theme-btn {
  background: transparent;
  border: none;
  color: var(--switcher-btn-color);
  padding: 6px;
  border-radius: 6px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s ease;
}

.theme-btn:hover {
  color: var(--switcher-btn-hover);
}

.theme-btn.active {
  background: var(--switcher-btn-active-bg);
  color: var(--switcher-btn-active-color);
  box-shadow: var(--switcher-btn-active-shadow);
}

/* --- Bit Configuration Section (Collapsible) --- */
.config-section {
  background: var(--vis-bg);
  border: 1px solid var(--input-border);
  border-radius: 10px;
  margin-bottom: 1.5rem;
  overflow: hidden;
  transition: background-color 0.25s ease, border-color 0.25s ease;
}

.config-header {
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.85rem 1.1rem;
  background: transparent;
  border: none;
  cursor: pointer;
  color: inherit;
  font: inherit;
  text-align: left;
  transition: background-color 0.2s ease;
}

.config-header:hover {
  background: rgba(0, 0, 0, 0.03);
}

[data-theme="dark"] .config-header:hover {
  background: rgba(255, 255, 255, 0.03);
}

.config-title {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 700;
  font-size: 0.92rem;
  color: var(--text-title);
  flex-wrap: wrap;
}

.config-title svg {
  color: var(--time);
  flex-shrink: 0;
}

.config-summary {
  font-size: 0.78rem;
  font-family: monospace;
  font-weight: 600;
  color: var(--text-muted);
  background: var(--card-bg);
  border: 1px solid var(--input-border);
  padding: 1px 6px;
  border-radius: 4px;
  margin-left: 0.25rem;
}

.config-header-right {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  flex-shrink: 0;
}

.chevron-icon {
  color: var(--text-muted);
  transition: transform 0.25s ease;
  flex-shrink: 0;
}

.config-section.open .chevron-icon {
  transform: rotate(180deg);
}

.config-status-badge {
  font-size: 0.78rem;
  font-family: monospace;
  font-weight: 700;
  padding: 3px 8px;
  border-radius: 6px;
  border: 1px solid var(--input-border);
  background: var(--card-bg);
  color: var(--text-muted);
  transition: all 0.2s ease;
}

.config-status-badge.valid {
  background: rgba(16, 185, 129, 0.12);
  color: #10b981;
  border-color: rgba(16, 185, 129, 0.3);
}

.config-status-badge.invalid {
  background: rgba(239, 68, 68, 0.12);
  color: #ef4444;
  border-color: rgba(239, 68, 68, 0.3);
}

.config-body {
  display: none;
  flex-direction: column;
  gap: 1rem;
  padding: 0 1.1rem 1.1rem 1.1rem;
  border-top: 1px solid var(--input-border);
  padding-top: 1rem;
}

.config-section.open .config-body {
  display: flex;
}

.bit-inputs-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 200px), 1fr));
  gap: 1rem;
}

.bit-input-item {
  background: var(--card-bg);
  border: 1px solid var(--input-border);
  border-radius: 8px;
  padding: 0.75rem 0.9rem;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  transition: background-color 0.25s ease, border-color 0.25s ease;
}

.bit-label-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 0.25rem;
  flex-wrap: wrap;
}

.bit-label-row label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--label-color);
}

.bit-capacity {
  font-size: 0.75rem;
  font-family: monospace;
  font-weight: 600;
  color: var(--text-muted);
}

.bit-input-wrapper {
  position: relative;
  display: flex;
  align-items: center;
}

.bit-input-wrapper input[type="number"] {
  padding: 0.45rem 2.5rem 0.45rem 0.65rem;
  font-size: 1.1rem;
  font-weight: 700;
  height: 38px;
}

.bit-unit {
  position: absolute;
  right: 0.75rem;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-muted);
  pointer-events: none;
}

.bit-hint {
  font-size: 0.72rem;
  color: var(--text-muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* --- Worker Segments Section --- */
.worker-segments-section {
  background: var(--card-bg);
  border: 1px solid var(--input-border);
  border-radius: 8px;
  padding: 0.85rem 0.9rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  min-width: 0;
  overflow: hidden;
}

.worker-segments-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.worker-segments-title {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.segments-title-text {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--label-color);
}

.btn-add-segment {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 0.75rem;
  font-weight: 600;
  padding: 3px 8px;
  border-radius: 5px;
  background: var(--vis-bg);
  color: var(--time);
  border: 1px solid var(--input-border);
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn-add-segment:hover {
  background: var(--time);
  color: #ffffff;
  border-color: var(--time);
}

.worker-segments-list {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.worker-segment-row {
  display: grid;
  grid-template-columns: auto 1fr 80px auto;
  align-items: center;
  gap: 0.5rem;
  background: var(--vis-bg);
  border: 1px solid var(--input-border);
  border-radius: 6px;
  padding: 0.4rem 0.5rem;
  transition: border-color 0.2s ease;
}

.segment-color-dot {
  width: 10px;
  height: 10px;
  border-radius: 2px;
  flex-shrink: 0;
}

.segment-name-input {
  font-size: 0.88rem !important;
  padding: 0.35rem 0.5rem !important;
  height: 32px !important;
  font-family: inherit !important;
  min-width: 0;
}

.segment-bits-wrapper {
  position: relative;
  display: flex;
  align-items: center;
}

.segment-bits-wrapper input[type="number"] {
  font-size: 0.95rem !important;
  padding: 0.35rem 2rem 0.35rem 0.5rem !important;
  height: 32px !important;
  text-align: right;
}

.segment-unit {
  position: absolute;
  right: 0.5rem;
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--text-muted);
  pointer-events: none;
}

.btn-remove-segment {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  padding: 0;
  border: none;
  background: transparent;
  color: var(--text-muted);
  border-radius: 5px;
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn-remove-segment:hover:not(:disabled) {
  color: #ef4444;
  background: rgba(239, 68, 68, 0.1);
}

.btn-remove-segment:disabled {
  opacity: 0.25;
  cursor: not-allowed;
}

.bit-allocation-bar {
  display: flex;
  height: 8px;
  width: 100%;
  border-radius: 999px;
  overflow: hidden;
  background: var(--input-border);
  box-shadow: inset 0 1px 2px rgba(0, 0, 0, 0.1);
}

.bar-segment {
  height: 100%;
  transition: width 0.3s ease;
}

.bar-segment.sign { background-color: var(--sign); }
.bar-segment.time { background-color: var(--time); }
.bar-segment.worker { background-color: var(--worker); }
.bar-segment.seq { background-color: var(--seq); }
.bar-segment.unused { background-color: #94a3b8; opacity: 0.3; }

.bit.unused {
  background-color: var(--input-border);
  color: var(--text-muted);
  opacity: 0.4;
}

.controls { 
  display: flex; 
  flex-direction: column; 
  gap: 1.25rem; 
  margin-bottom: 2rem; 
}

.time-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 280px), 1fr));
  gap: 1.5rem;
}

.sliders-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 240px), 1fr));
  gap: 1.5rem;
}

.input-group { 
  display: flex; 
  flex-direction: column; 
  gap: 0.5rem; 
  min-width: 0;
}

.label-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  min-height: 24px;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.epoch-presets {
  display: inline-flex;
  gap: 4px;
  flex-wrap: wrap;
}

.preset-btn {
  font-size: 0.75rem;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: 6px;
  background: var(--vis-bg);
  color: var(--text-muted);
  border: 1px solid var(--input-border);
  cursor: pointer;
  transition: all 0.2s ease;
}

.preset-btn:hover {
  color: var(--text);
  border-color: var(--time);
}

.preset-btn.active {
  background: var(--time);
  color: #ffffff;
  border-color: var(--time);
}

.now-btn {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-size: 0.8rem;
  font-weight: 600;
  padding: 3px 10px;
  border-radius: 6px;
  background: var(--vis-bg);
  color: var(--time);
  border: 1px solid var(--input-border);
  cursor: pointer;
  transition: all 0.2s ease;
}

.now-btn:hover {
  background: var(--time);
  color: #ffffff;
  border-color: var(--time);
}

.now-btn:active {
  transform: scale(0.95);
}

.date-preview {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.82rem;
  color: var(--text-muted);
  font-family: monospace;
  margin-top: 2px;
}

.date-preview svg {
  color: var(--time);
  flex-shrink: 0;
}

label { 
  font-weight: 600; 
  font-size: 0.9rem; 
  color: var(--label-color); 
}

.value-badge {
  font-size: 0.85rem;
  font-family: monospace;
  font-weight: 700;
  padding: 2px 8px;
  border-radius: 6px;
  background: var(--vis-bg);
  border: 1px solid var(--input-border);
  color: var(--text);
  transition: all 0.2s ease;
}

.value-badge.worker-badge {
  color: var(--worker);
}

.value-badge.seq-badge {
  color: var(--seq);
}

input[type="number"],
input[type="date"],
input[type="datetime-local"] { 
  width: 100%;
  min-width: 0;
  padding: 0.75rem; 
  background-color: var(--input-bg);
  color: var(--text);
  border: 1px solid var(--input-border); 
  border-radius: 6px; 
  font-size: 1rem; 
  transition: border-color 0.2s, background-color 0.25s, color 0.25s; 
  font-family: monospace; 
}

input[type="number"]:focus,
input[type="date"]:focus,
input[type="datetime-local"]:focus { 
  outline: none; 
  border-color: var(--time); 
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.2); 
}

input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 8px;
  background: var(--vis-bg);
  border: 1px solid var(--input-border);
  border-radius: 999px;
  outline: none;
  padding: 0;
  margin: 14px 0 10px 0;
  cursor: pointer;
  transition: background-color 0.25s, border-color 0.25s;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--thumb-color, var(--time));
  border: 3px solid var(--card-bg);
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.25);
  cursor: pointer;
  transition: transform 0.15s ease;
}

input[type="range"]::-moz-range-thumb {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--thumb-color, var(--time));
  border: 3px solid var(--card-bg);
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.25);
  cursor: pointer;
  transition: transform 0.15s ease;
}

input[type="range"]:hover::-webkit-slider-thumb,
input[type="range"]:active::-webkit-slider-thumb {
  transform: scale(1.2);
}

input[type="range"]:hover::-moz-range-thumb,
input[type="range"]:active::-moz-range-thumb {
  transform: scale(1.2);
}

.visualization { 
  margin-bottom: 2rem; 
  background: var(--vis-bg); 
  padding: 1.5rem; 
  border-radius: 8px; 
  transition: background-color 0.25s ease;
}

.bits-grid { 
  display: grid; 
  grid-template-columns: repeat(32, minmax(0, 1fr)); 
  gap: 4px; 
  justify-content: center; 
  align-items: center;
}

.bit { 
  width: 100%; 
  height: 32px; 
  display: flex; 
  align-items: center; 
  justify-content: center; 
  font-size: 13px; 
  font-weight: 700;
  font-family: monospace; 
  color: #ffffff; 
  border-radius: 4px; 
  transition: transform 0.15s ease, filter 0.15s ease; 
}

/* Colors based on sections */
.bit.sign { background-color: var(--sign); }
.bit.time { background-color: var(--time); }
.bit.worker { background-color: var(--worker); }
.bit.seq { background-color: var(--seq); }

/* Effect when value changes */
.bit.highlight { 
  transform: scale(1.2); 
  filter: brightness(1.25); 
  z-index: 10; 
}

.legend { 
  display: flex; 
  flex-wrap: wrap; 
  gap: 1.5rem; 
  justify-content: center; 
  margin-top: 1.5rem; 
}

.legend-item { 
  display: flex; 
  align-items: center; 
  gap: 0.5rem; 
  font-size: 0.85rem; 
  font-weight: 500; 
  color: var(--text-muted);
}

.dot { 
  width: 14px; 
  height: 14px; 
  border-radius: 3px; 
}

.result-panel { 
  background: var(--panel-bg); 
  border: 2px dashed var(--panel-border); 
  border-radius: 8px; 
  padding: 1.25rem 1.5rem; 
  text-align: center; 
  transition: background-color 0.25s ease, border-color 0.25s ease;
}

.result-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.25rem;
}

.result-label { 
  font-size: 0.875rem; 
  color: var(--text-muted); 
  text-transform: uppercase; 
  letter-spacing: 0.05em; 
  font-weight: 600; 
}

.copy-btn {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-size: 0.78rem;
  font-weight: 600;
  padding: 3px 8px;
  border-radius: 5px;
  background: var(--vis-bg);
  color: var(--text-muted);
  border: 1px solid var(--input-border);
  cursor: pointer;
  transition: all 0.2s ease;
}

.copy-btn:hover {
  color: var(--text);
  border-color: var(--time);
}

.copy-btn:active {
  transform: scale(0.95);
}

.final-id-container {
  margin: 0.25rem 0;
}

.final-id-input { 
  width: 100%;
  min-width: 0;
  text-align: center;
  background: transparent;
  border: 1px solid transparent;
  border-radius: 8px;
  padding: 0.25rem 0.5rem;
  font-size: 2rem; 
  font-weight: 700; 
  color: var(--time); 
  font-family: monospace; 
  transition: border-color 0.2s, background-color 0.2s, box-shadow 0.2s;
}

.final-id-input:hover {
  border-color: var(--input-border);
  background: var(--vis-bg);
}

.final-id-input:focus { 
  outline: none; 
  border-color: var(--time); 
  background: var(--input-bg);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.2); 
}

.decode-hint {
  margin-top: 0.25rem;
  font-size: 0.78rem;
  color: var(--text-muted);
}

@media (max-width: 768px) {
  .bits-grid {
    grid-template-columns: repeat(16, minmax(0, 1fr));
    gap: 5px;
  }
  .bit {
    height: 30px;
    font-size: 12px;
  }
}

@media (max-width: 480px) {
  .card {
    padding: 4.25rem 1.25rem 1.5rem 1.25rem;
  }
  .header-actions {
    top: 1rem;
    right: 1rem;
  }
  .bits-grid {
    grid-template-columns: repeat(8, minmax(0, 1fr));
    gap: 6px;
  }
  .bit {
    height: 34px;
    font-size: 14px;
  }
  .config-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.75rem;
  }
  .config-header-right {
    width: 100%;
    justify-content: space-between;
  }
  .bit-inputs-grid {
    grid-template-columns: 1fr;
  }
  .worker-segment-row {
    grid-template-columns: auto 1fr auto;
    row-gap: 0.5rem;
  }
  .segment-bits-wrapper {
    grid-column: 1 / -1;
  }
}

input:disabled, button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}