*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --bg:             #0d1117;
  --bg-surface:     #161b22;
  --bg-elevated:    #1c2128;
  --bg-input:       #21262d;
  --bg-input-hover: #30363d;
  --border:         #30363d;
  --text:           #c9d1d9;
  --text-strong:    #e6edf3;
  --text-muted:     #8b949e;
  --text-dim:       #484f58;
  --accent:         #58a6ff;
  --accent-bg:      rgba(56, 139, 253, 0.1);
  --accent-border:  #388bfd;
  --positive:       #3fb950;
  --positive-bg:    rgba(63, 185, 80, 0.12);
  --negative:       #f85149;
  --negative-bg:    rgba(248, 81, 73, 0.12);
}

[data-theme="light"] {
  --bg:             #ffffff;
  --bg-surface:     #f6f8fa;
  --bg-elevated:    #ffffff;
  --bg-input:       #f6f8fa;
  --bg-input-hover: #eaeef2;
  --border:         #d0d7de;
  --text:           #1f2328;
  --text-strong:    #1f2328;
  --text-muted:     #57606a;
  --text-dim:       #8c959f;
  --accent:         #0969da;
  --accent-bg:      rgba(9, 105, 218, 0.1);
  --accent-border:  #0969da;
  --positive:       #1a7f37;
  --positive-bg:    rgba(26, 127, 55, 0.1);
  --negative:       #cf222e;
  --negative-bg:    rgba(207, 34, 46, 0.1);
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
  display: flex;
  flex-direction: column;
  height: 100dvh;
  overflow: hidden;
}

header {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  padding: 0.6rem 1rem;
  background: var(--bg-surface);
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}

#logo {
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--accent);
  text-transform: lowercase;
  flex-shrink: 0;
}

#controls {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex: 1;
}

select {
  background: var(--bg-input);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.3rem 0.6rem;
  font-size: 0.85rem;
  cursor: pointer;
  min-width: 180px;
}

select:focus {
  outline: none;
  border-color: var(--accent);
}

select:disabled {
  opacity: 0.5;
  cursor: default;
}

#meta {
  font-size: 0.75rem;
  color: var(--text-muted);
}

#hint {
  font-size: 0.7rem;
  color: var(--text-dim);
  flex-shrink: 0;
}

main {
  flex: 1;
  display: flex;
  flex-direction: row;
  overflow: hidden;
  min-height: 0;
}

#chart-wrap {
  flex: 1;
  position: relative;
  overflow: hidden;
  min-width: 0;
}

canvas {
  display: block;
  width: 100%;
  height: 100%;
  cursor: crosshair;
  user-select: none;
}

canvas.dragging {
  cursor: grabbing;
}

#status {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 0.85rem;
  color: var(--text-muted);
  pointer-events: none;
  text-align: center;
}

.spinner {
  width: 28px;
  height: 28px;
  border: 3px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
  margin: 0 auto;
}

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

#tooltip {
  display: none;
  position: fixed;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 13px;
  font-size: 0.8rem;
  pointer-events: none;
  z-index: 100;
  max-width: 300px;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.5);
}

.tip-summary {
  color: var(--text-strong);
  font-weight: 600;
  margin-bottom: 7px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 260px;
}

.tip-row {
  display: flex;
  gap: 8px;
  color: var(--text);
  line-height: 1.7;
}

.tip-label {
  color: var(--text-dim);
  min-width: 44px;
  flex-shrink: 0;
}

.tip-delta {
  font-size: 0.78em;
  font-family: monospace;
  padding: 1px 5px;
  border-radius: 4px;
}

.tip-delta.pos {
  color: var(--positive);
  background: var(--positive-bg);
}

.tip-delta.neg {
  color: var(--negative);
  background: var(--negative-bg);
}

#view-switcher {
  display: flex;
  flex-shrink: 0;
}

.view-btn {
  position: relative;
  background: var(--bg-input);
  color: var(--text-muted);
  border: 1px solid var(--border);
  padding: 0.3rem 0.65rem;
  font-size: 0.8rem;
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
}

.view-btn:first-child {
  border-radius: 6px 0 0 6px;
}

.view-btn:last-child {
  border-radius: 0 6px 6px 0;
}

#view-switcher .view-btn:not(:first-child) {
  margin-left: -1px;
}

.view-btn.active {
  z-index: 1;
  background: var(--accent-bg);
  color: var(--accent);
  border-color: var(--accent-border);
}

.view-btn:hover:not(.active) {
  background: var(--bg-input-hover);
  color: var(--text);
}


#legend {
  width: max-content;
  min-width: 120px;
  flex-shrink: 0;
  display: flex;
  flex-direction: column;
  gap: 3px;
  padding: 10px;
  font-size: 0.75rem;
  overflow-x: hidden;
  overflow-y: auto;
  border-left: 1px solid var(--border);
  background: var(--bg-surface);
  scrollbar-width: thin;
  scrollbar-color: var(--border) transparent;
}

#legend::-webkit-scrollbar {
  width: 4px;
}

#legend::-webkit-scrollbar-track {
  background: transparent;
}

#legend::-webkit-scrollbar-thumb {
  background: var(--border);
  border-radius: 2px;
}

#legend::-webkit-scrollbar-thumb:hover {
  background: var(--text-dim);
}

#legend-handle {
  flex-shrink: 0;
  width: 4px;
  cursor: col-resize;
  background: var(--border);
  transition: background 0.15s;
}

#legend-handle:hover,
#legend-handle.dragging {
  background: var(--accent);
}

#legend-handle[hidden] { display: none; }

#legend[hidden] { display: none; }

.legend-item {
  display: flex;
  align-items: center;
  gap: 6px;
  line-height: 1.4;
  border-radius: 3px;
  padding: 1px 3px;
  margin: 0 -3px;
  transition: opacity 0.15s;
}

.legend-item:hover {
  background: var(--bg-input-hover);
}

.legend-item--hidden {
  opacity: 0.45;
}

.legend-item--hidden .legend-label {
  text-decoration: line-through;
  color: var(--text-muted);
}

.legend-swatch {
  display: inline-block;
  width: 10px;
  height: 10px;
  border-radius: 2px;
  flex-shrink: 0;
}

.legend-label {
  color: var(--text);
  white-space: nowrap;
}

#settings-wrap {
  position: relative;
  flex-shrink: 0;
}

#settings-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-input);
  color: var(--text-muted);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.3rem 0.5rem;
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
}

#settings-btn:hover,
#settings-btn.open {
  background: var(--bg-input-hover);
  color: var(--text);
}

#settings-panel {
  position: absolute;
  top: calc(100% + 6px);
  right: 0;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px 14px;
  z-index: 200;
  min-width: 220px;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.5);
  display: flex;
  flex-direction: column;
  gap: 10px;
}

#settings-panel[hidden] { display: none; }

.settings-row {
  display: flex;
  align-items: center;
  gap: 10px;
}

.settings-label {
  font-size: 0.78rem;
  color: var(--text-muted);
  min-width: 46px;
}

.settings-row select {
  min-width: unset;
  flex: 1;
  font-size: 0.8rem;
  padding: 0.25rem 0.5rem;
}

.view-switcher-inline {
  display: flex;
  flex: 1;
}

.view-switcher-inline .view-btn {
  flex: 1;
  font-size: 0.78rem;
  position: relative;
}

.view-switcher-inline .view-btn:first-child {
  border-radius: 6px 0 0 6px;
}

.view-switcher-inline .view-btn:last-child {
  border-radius: 0 6px 6px 0;
}

.view-switcher-inline .view-btn:not(:first-child) {
  border-radius: 0;
  margin-left: -1px;
}

.view-switcher-inline .view-btn.active {
  z-index: 1;
}

footer {
  flex-shrink: 0;
  padding: 0.35rem 1rem;
  background: var(--bg-surface);
  border-top: 1px solid var(--border);
  font-size: 0.72rem;
  text-align: center;
}

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

footer a:hover {
  color: var(--text-muted);
}

/* ── Responsive layout ────────────────────────────────────────────────────── */

@media (max-width: 640px) {
  header {
    flex-wrap: wrap;
    gap: 0.5rem 0.75rem;
    padding: 0.5rem 0.75rem;
  }

  /* Row 1: logo (expands) + settings button */
  #logo {
    order: 1;
    flex: 1;
  }

  #settings-wrap {
    order: 2;
  }

  /* Row 2: controls */
  #controls {
    order: 3;
    width: 100%;
    flex: none;
    flex-wrap: wrap;
    gap: 0.4rem;
  }

  main {
    flex-direction: column;
  }

  #legend-handle {
    width: 100%;
    height: 4px;
    cursor: row-resize;
  }

  #legend {
    width: 100%;
    max-width: none;
    flex-direction: row;
    flex-wrap: wrap;
    border-left: none;
    border-top: none;
    max-height: 130px;
    overflow-x: hidden;
    overflow-y: auto;
    gap: 6px 14px;
  }

  #hint {
    display: none;
  }

  select {
    min-width: 0;
    flex: 1;
  }

  #meta {
    width: 100%;
    font-size: 0.72rem;
  }

  /* Larger tap targets */
  .view-btn {
    padding: 0.45rem 0.7rem;
    min-height: 36px;
  }

  #settings-btn {
    padding: 0.45rem 0.6rem;
    min-height: 36px;
  }
}

@media (max-width: 400px) {
  #meta {
    display: none;
  }
}