/* Modern-soft theme: design tokens up top, everything else derives from
 * them. html[data-theme] is set before this sheet loads (see index.html)
 * and toggled from main.js; the canvas mirrors it via GP.renderer themes.
 */

:root,
html[data-theme="light"] {
  color-scheme: light;
  --bg-app: #eef0f4;
  --surface: #ffffff;
  --surface-2: #f5f6f9;
  --border: rgba(18, 26, 46, 0.08);
  --border-strong: rgba(18, 26, 46, 0.16);
  --text: #1a2233;
  --text-2: #5b6472;
  --text-3: #98a0af;
  --accent: #4c6fff;
  --accent-hover: #3d5ef0;
  --accent-soft: rgba(76, 111, 255, 0.10);
  --row-focus: rgba(76, 111, 255, 0.05);
  --danger: #c74440;
  --shadow-1: 0 1px 2px rgba(18, 26, 46, 0.05), 0 4px 16px rgba(18, 26, 46, 0.07);
  --shadow-2: 0 4px 12px rgba(18, 26, 46, 0.12), 0 16px 40px rgba(18, 26, 46, 0.14);
  --radius: 14px;
  --radius-sm: 8px;
}

html[data-theme="dark"] {
  color-scheme: dark;
  --bg-app: #14161a;
  --surface: #1e2126;
  --surface-2: #262a31;
  --border: rgba(255, 255, 255, 0.08);
  --border-strong: rgba(255, 255, 255, 0.16);
  --text: #e7eaf0;
  --text-2: #a6adbb;
  --text-3: #6d7583;
  --accent: #7c93ff;
  --accent-hover: #92a6ff;
  --accent-soft: rgba(124, 147, 255, 0.14);
  --row-focus: rgba(124, 147, 255, 0.07);
  --danger: #e06561;
  --shadow-1: 0 1px 2px rgba(0, 0, 0, 0.4), 0 4px 16px rgba(0, 0, 0, 0.3);
  --shadow-2: 0 4px 12px rgba(0, 0, 0, 0.5), 0 16px 40px rgba(0, 0, 0, 0.45);
}

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

html, body { height: 100%; }

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

button { font-family: inherit; }

/* ---- Top bar ---- */

#topbar {
  flex: none;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 16px;
}

.tb-left { display: flex; align-items: center; gap: 14px; }
.tb-right { display: flex; align-items: center; gap: 10px; }

.logo {
  font-size: 21px;
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--text);
}
.logo::after { content: "."; color: var(--accent); }

#graph-title {
  background: transparent;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  color: var(--text-2);
  font-size: 14px;
  padding: 6px 10px;
  width: 180px;
  transition: background 0.15s, border-color 0.15s;
}
#graph-title:hover { background: var(--surface); border-color: var(--border); }
#graph-title:focus {
  outline: none;
  background: var(--surface);
  border-color: var(--accent);
  color: var(--text);
}

#theme-btn {
  width: 36px;
  height: 36px;
  border: 1px solid var(--border);
  border-radius: 50%;
  background: var(--surface);
  color: var(--text-2);
  font-size: 16px;
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
}
#theme-btn:hover { background: var(--surface-2); color: var(--text); }

#share-btn {
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 999px;
  padding: 9px 20px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  box-shadow: var(--shadow-1);
  transition: background 0.15s, transform 0.15s;
}
#share-btn:hover { background: var(--accent-hover); transform: translateY(-1px); }
#share-btn:active { transform: none; }

/* ---- Layout: floating cards ---- */

#app {
  flex: 1;
  display: flex;
  min-height: 0;
  gap: 12px;
  padding: 0 12px 12px;
}

#sidebar {
  flex: none;
  width: 340px;
  display: flex;
  flex-direction: column;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-1);
  overflow: hidden;
}
body.collapsed #sidebar { display: none; }

/* ---- Expression toolbar ---- */

#expr-toolbar {
  flex: none;
  height: 46px;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 4px;
  padding: 0 8px;
}

#expr-toolbar button {
  width: 34px;
  height: 32px;
  border: none;
  border-radius: var(--radius-sm);
  background: transparent;
  font-size: 18px;
  color: var(--text-2);
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
}
#expr-toolbar button:hover { background: var(--accent-soft); color: var(--text); }
#expr-toolbar button:disabled {
  opacity: 0.35;
  cursor: default;
  background: transparent;
}
#collapse-btn { margin-left: auto; }

/* ---- Expression rows ---- */

#expr-list { flex: 1; overflow-y: auto; overflow-x: hidden; }

#expr-list::-webkit-scrollbar { width: 8px; }
#expr-list::-webkit-scrollbar-thumb {
  background: var(--border-strong);
  border-radius: 4px;
}

.expr-row {
  position: relative;
  display: flex;
  min-height: 50px;
  border-bottom: 1px solid var(--border);
  transition: background 0.15s;
}
.expr-row:focus-within {
  background: var(--row-focus);
  box-shadow: inset 3px 0 0 var(--accent);
}

.expr-gutter {
  flex: none;
  width: 46px;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 4px 0 8px;
  background: var(--surface-2);
}

.expr-index {
  align-self: flex-start;
  padding-left: 6px;
  font-size: 10px;
  color: var(--text-3);
}

.color-btn {
  width: 22px;
  height: 22px;
  margin-top: 2px;
  border-radius: 50%;
  border: 3px solid #888;
  background: #888;
  cursor: pointer;
  padding: 0;
  transition: transform 0.12s;
}
.color-btn:hover { transform: scale(1.12); }

.expr-main {
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 5px 24px 5px 8px;
}

math-field.expr-input {
  width: 100%;
  border: none;
  font-size: 17px;
  padding: 7px 4px;
  background: transparent;
  color: var(--text);
  --caret-color: var(--accent);
  --selection-background-color: var(--accent-soft);
}
math-field.expr-input:focus,
math-field.expr-input:focus-within {
  outline: none;
}
/* The row supplies its own chrome; hide MathLive's built-in toggles. */
math-field.expr-input::part(menu-toggle),
math-field.expr-input::part(virtual-keyboard-toggle) {
  display: none;
}

.expr-error {
  color: var(--danger);
  font-size: 11px;
  padding: 0 4px 5px;
}
.expr-error:empty { display: none; }

.expr-value {
  color: var(--text-2);
  font-size: 13px;
  padding: 0 6px 7px;
}
.expr-value:empty { display: none; }

.expr-slider {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 0 4px 10px;
}
.expr-slider[hidden] { display: none; }
.expr-slider input[type="range"] { flex: 1; min-width: 60px; }

.slider-play {
  flex: none;
  width: 26px;
  height: 26px;
  border: none;
  border-radius: 50%;
  background: var(--accent);
  color: #fff;
  font-size: 10px;
  line-height: 1;
  cursor: pointer;
  padding: 0;
  transition: background 0.15s;
}
.slider-play:hover { background: var(--accent-hover); }

.slider-bound-input {
  flex: none;
  width: 44px;
  border: none;
  background: transparent;
  font-size: 12px;
  color: var(--text-3);
  text-align: center;
  padding: 3px 2px;
  border-radius: var(--radius-sm);
  transition: background 0.15s;
}
.slider-bound-input:hover { background: var(--surface-2); }
.slider-bound-input:focus {
  outline: 1px solid var(--accent);
  background: var(--surface);
  color: var(--text);
}

.expr-delete {
  position: absolute;
  top: 4px;
  right: 6px;
  border: none;
  background: none;
  color: var(--text-3);
  font-size: 17px;
  line-height: 1;
  cursor: pointer;
  opacity: 0;
  transition: opacity 0.12s, color 0.12s;
}
.expr-row:hover .expr-delete,
.expr-row:focus-within .expr-delete { opacity: 1; }
.expr-delete:hover { color: var(--text); }

/* ---- Color chooser popover ---- */

.color-popover {
  position: fixed;
  z-index: 20;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  box-shadow: var(--shadow-2);
  padding: 12px;
}

.color-swatches {
  display: grid;
  grid-template-columns: repeat(3, 28px);
  gap: 9px;
}

.color-swatch {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  border: 2px solid var(--border);
  cursor: pointer;
  padding: 0;
  transition: transform 0.12s;
}
.color-swatch:hover { transform: scale(1.14); }
.color-swatch.selected {
  border-color: var(--accent);
  box-shadow: 0 0 0 2px var(--surface) inset;
}

.color-custom {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-top: 12px;
  font-size: 12px;
  color: var(--text-2);
  cursor: pointer;
}
.color-custom input[type="color"] {
  width: 28px;
  height: 28px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 1px;
  background: none;
  cursor: pointer;
}

/* ---- Graph area ---- */

#graph-wrap {
  flex: 1;
  position: relative;
  min-width: 0;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-1);
  overflow: hidden;
}

#graph {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  touch-action: none;
  cursor: grab;
}
#graph:active { cursor: grabbing; }

#graph-controls {
  position: absolute;
  top: 14px;
  right: 14px;
  display: flex;
  flex-direction: column;
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  box-shadow: var(--shadow-1);
  background: var(--surface); /* fallback for no color-mix */
  background: color-mix(in srgb, var(--surface) 80%, transparent);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

#graph-controls button {
  width: 38px;
  height: 38px;
  border: none;
  background: transparent;
  font-size: 18px;
  color: var(--text-2);
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
}
#graph-controls button:hover { background: var(--accent-soft); color: var(--text); }

#expand-btn {
  position: absolute;
  top: 14px;
  left: 14px;
  width: 38px;
  height: 38px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--surface); /* fallback for no color-mix */
  background: color-mix(in srgb, var(--surface) 80%, transparent);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  font-size: 16px;
  color: var(--text-2);
  cursor: pointer;
  box-shadow: var(--shadow-1);
  transition: background 0.15s, color 0.15s;
}
#expand-btn:hover { background: var(--accent-soft); color: var(--text); }

/* ---- Toast ---- */

#toast {
  position: fixed;
  bottom: 28px;
  left: 50%;
  transform: translateX(-50%);
  background: rgba(20, 22, 28, 0.92);
  color: #fff;
  font-size: 14px;
  padding: 10px 22px;
  border-radius: 999px;
  box-shadow: var(--shadow-2);
  z-index: 10;
}

/* ---- Narrow screens ---- */

@media (max-width: 640px) {
  #sidebar { width: 270px; }
  .logo { display: none; }
  #app { padding: 0 8px 8px; gap: 8px; }
}