/* ============================================================
   DIAGRAM GENERATOR APP — MAIN STYLESHEET
   Adheres to the project design system & tokens contract.
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Hanken+Grotesk:wght@400;500;600;700;800;900&family=Spectral:ital,wght@0,400;0,500;0,600;1,400;1,500&family=IBM+Plex+Mono:wght@400;500;600&display=swap');

:root {
  /* color theme variables (light theme default) */
  --paper: #EDF1EC;
  --paper-2: #E4EAE3;
  --paper-3: #DBE2D9;
  --card: #F5F8F4;
  --ink: #16201C;
  --ink-soft: #3A463F;
  --ink-mute: #6B756D;

  --accent: #D6452A;
  --accent-soft: #E68A77;
  --good: #2E7D57;
  --good-soft: #6FAF8F;

  /* diagram + heat-map families */
  --nucleus: #D6452A;
  --electron: #2E7D57;
  --shell: rgba(22, 32, 28, 0.35);
  --cool: #3E6FA5;
  --hot: #D6452A;
  --water: #3E6FA5;

  /* structure */
  --grid: rgba(22, 32, 28, 0.02);
  --grid-bold: rgba(22, 32, 28, 0.04);
  --hair: rgba(22, 32, 28, 0.16);
  --hair-soft: rgba(22, 32, 28, 0.09);

  /* type */
  --display: 'Hanken Grotesk', system-ui, sans-serif;
  --serif: 'Spectral', Georgia, serif;
  --mono: 'IBM Plex Mono', ui-monospace, monospace;

  /* Diagram geometry tokens */
  --dia-r-particle: 2;
  --dia-r-atom-sm: 5;
  --dia-r-atom: 7.5;
  --dia-stroke: 1;
  --dia-stroke-bond: 1.2;
  --dia-label-size: 10px;
  --dia-caption-size: 7px;
}

:root.dark {
  --paper: #131A17;
  --paper-2: #18211D;
  --paper-3: #1F2A25;
  --card: #1B2420;
  --ink: #E7EDE6;
  --ink-soft: #C3CCC2;
  --ink-mute: #8A948B;

  --accent: #F26B4E;
  --accent-soft: #9E4636;
  --good: #5FB088;
  --good-soft: #3A6B53;

  --nucleus: #F26B4E;
  --electron: #5FB088;
  --shell: rgba(231, 237, 230, 0.32);
  --cool: #6B9BD0;
  --hot: #F26B4E;
  --water: #6B9BD0;

  --grid: rgba(231, 237, 230, 0.012);
  --grid-bold: rgba(231, 237, 230, 0.025);
  --hair: rgba(231, 237, 230, 0.16);
  --hair-soft: rgba(231, 237, 230, 0.08);
}

/* ============================================================
   BASE SETUP
   ============================================================ */

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

body {
  font-family: var(--serif);
  font-size: 18px;
  line-height: 1.5;
  color: var(--ink);
  background-color: var(--paper);
  background-image:
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 26px 26px, 26px 26px;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow: hidden;
  height: 100vh;
  display: flex;
  flex-direction: column;
  transition: background-color 0.3s ease, color 0.3s ease;
}

/* Scrollbars */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}
::-webkit-scrollbar-track {
  background: var(--paper-2);
}
::-webkit-scrollbar-thumb {
  background: var(--ink-mute);
  border-radius: 4px;
}
::-webkit-scrollbar-thumb:hover {
  background: var(--ink-soft);
}

/* Headings */
h1, h2, h3, h4 {
  font-family: var(--display);
  font-weight: 800;
  color: var(--ink);
}

button, input, select, textarea {
  font-family: inherit;
  font-size: inherit;
  color: inherit;
}

/* ============================================================
   APP LAYOUT
   ============================================================ */

.app-header {
  height: 60px;
  background: var(--paper-2);
  border-bottom: 1px solid var(--hair);
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0 1.5rem;
  z-index: 10;
  box-shadow: 0 2px 8px rgba(0,0,0,0.05);
}

.app-title-group {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.app-title-group h1 {
  font-size: 1.25rem;
  letter-spacing: -0.01em;
  font-weight: 800;
}

.app-title-group span {
  font-family: var(--mono);
  font-size: 0.7rem;
  padding: 0.2rem 0.5rem;
  background: var(--accent);
  color: white;
  border-radius: 4px;
  letter-spacing: 0.05em;
  font-weight: 600;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.theme-toggle {
  background: none;
  border: 1px solid var(--hair);
  cursor: pointer;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s;
}

.theme-toggle:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--paper-3);
}

.theme-toggle svg {
  width: 18px;
  height: 18px;
  fill: currentColor;
}

/* Main Grid Layout */
.app-container {
  flex: 1;
  display: grid;
  grid-template-columns: 380px 1fr;
  height: calc(100vh - 60px);
  overflow: hidden;
}

/* ============================================================
   SIDEBAR & CONTROLS
   ============================================================ */

.sidebar {
  background: var(--paper-2);
  border-right: 1px solid var(--hair);
  display: flex;
  flex-direction: column;
  overflow-y: auto;
  box-shadow: 2px 0 8px rgba(0,0,0,0.02);
}

/* Category Tabs */
.tabs-nav {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  background: var(--paper-3);
  border-bottom: 1px solid var(--hair);
}

.tab-btn {
  background: none;
  border: none;
  padding: 0.75rem 0.25rem;
  font-family: var(--display);
  font-weight: 700;
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--ink-mute);
  cursor: pointer;
  text-align: center;
  transition: all 0.2s;
  border-bottom: 2px solid transparent;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.25rem;
}

.tab-btn svg {
  width: 16px;
  height: 16px;
  fill: currentColor;
}

.tab-btn:hover {
  color: var(--accent);
  background: var(--paper-2);
}

.tab-btn.active {
  color: var(--ink);
  background: var(--paper-2);
  border-bottom-color: var(--accent);
}

/* Sidebar Panels content */
.panel-content {
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.form-group label {
  font-family: var(--display);
  font-weight: 700;
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--ink-soft);
}

.form-input {
  width: 100%;
  padding: 0.55rem 0.75rem;
  border: 1px solid var(--hair);
  background: var(--card);
  border-radius: 6px;
  font-size: 0.9rem;
  font-weight: 500;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.form-input:focus {
  border-color: var(--accent);
  outline: none;
  box-shadow: 0 0 0 2px var(--accent-soft);
}

.form-checkbox {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  cursor: pointer;
  font-size: 0.85rem;
  font-weight: 600;
}

.form-checkbox input {
  width: 16px;
  height: 16px;
  accent-color: var(--accent);
}

/* Adjuster row for charge/numbers */
.adjuster {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.adjuster-btn {
  width: 32px;
  height: 32px;
  border-radius: 6px;
  border: 1px solid var(--hair);
  background: var(--card);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
  cursor: pointer;
  transition: all 0.2s;
}

.adjuster-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--paper-3);
}

.adjuster-val {
  font-family: var(--mono);
  font-weight: bold;
  font-size: 1rem;
  width: 40px;
  text-align: center;
}

/* Chip/Selector lists */
.chips-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-top: 0.25rem;
}

.chip {
  font-family: var(--mono);
  font-size: 0.72rem;
  font-weight: 500;
  padding: 0.4rem 0.6rem;
  background: var(--card);
  border: 1px solid var(--hair);
  color: var(--ink-soft);
  cursor: pointer;
  border-radius: 4px;
  transition: all 0.15s ease;
}

.chip:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.chip.active {
  background: var(--ink);
  color: var(--paper);
  border-color: var(--ink);
}

/* JSON Edit Box */
.json-textarea {
  font-family: var(--mono);
  font-size: 0.75rem;
  line-height: 1.4;
  height: 160px;
  resize: vertical;
  background: var(--paper);
  color: var(--ink);
  padding: 0.5rem;
  border: 1px solid var(--hair);
  border-radius: 4px;
}

/* Info pill alerts */
.info-box {
  background: var(--paper-3);
  padding: 0.75rem;
  border-left: 3px solid var(--accent);
  font-size: 0.8rem;
  line-height: 1.45;
  border-radius: 0 6px 6px 0;
  font-family: var(--serif);
}

.info-box.success {
  border-left-color: var(--good);
  background: rgba(46, 125, 87, 0.05);
}

.info-box.warning {
  border-left-color: var(--accent);
  background: rgba(214, 69, 42, 0.05);
}

/* ============================================================
   PREVIEW PANEL & CANVAS
   ============================================================ */

.preview-panel {
  display: flex;
  flex-direction: column;
  overflow: hidden;
  position: relative;
}

.preview-bar {
  height: 48px;
  background: var(--paper-2);
  border-bottom: 1px solid var(--hair);
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0 1.25rem;
}

.preview-title {
  font-family: var(--display);
  font-weight: 700;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--ink-soft);
}

.preview-actions {
  display: flex;
  gap: 0.5rem;
}

.action-btn {
  font-family: var(--display);
  font-weight: 700;
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 0.4rem 0.75rem;
  border: 1px solid var(--hair);
  border-radius: 4px;
  background: var(--card);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  transition: all 0.15s;
}

.action-btn svg {
  width: 14px;
  height: 14px;
  fill: currentColor;
}

.action-btn:hover {
  background: var(--paper-3);
  border-color: var(--ink);
}

.action-btn.primary {
  background: var(--accent);
  color: white;
  border-color: var(--accent);
}

.action-btn.primary:hover {
  background: #b5331b;
  border-color: #b5331b;
}

/* Live Canvas Area */
.canvas-area {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2rem;
  overflow-y: auto;
  position: relative;
}

/* Background graph grid */
.canvas-bg-grid {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  background-image:
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 26px 26px, 26px 26px;
  z-index: 0;
}

/* Main Graphic Frame wrapper */
.graphic-frame {
  background: var(--card);
  border: 1px solid var(--hair);
  border-radius: 8px;
  padding: 1.5rem;
  box-shadow: 0 10px 25px rgba(0,0,0,0.03);
  max-width: 90%;
  max-height: 90%;
  min-width: 320px;
  z-index: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  transition: all 0.3s ease;
}

.graphic-frame svg {
  max-width: 100%;
  max-height: 550px;
  display: block;
}

/* Legend styled elements in the graphic frame */
.legend {
  margin-top: 1rem;
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  justify-content: center;
  font-family: var(--mono);
  font-size: 0.72rem;
}

.swatch {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  color: var(--ink-soft);
}

.chip-swatch {
  width: 10px;
  height: 10px;
  border: 1px solid var(--ink);
  flex-shrink: 0;
}

/* Custom molecule builder row inputs */
.builder-row {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr auto;
  gap: 0.4rem;
  align-items: center;
}

.delete-row-btn {
  background: none;
  border: none;
  color: var(--accent);
  cursor: pointer;
  padding: 0.2rem;
  display: flex;
  align-items: center;
}

.delete-row-btn:hover {
  color: #b5331b;
}

/* ============================================================
   DIAGRAM CLASSES (Matching DIAGRAM_CONTRACT.md / components.css)
   ============================================================ */

.atom-shell {
  fill: none;
  stroke: var(--shell);
  stroke-width: 1;
}

.atom-e {
  fill: var(--electron);
  stroke: var(--ink);
  stroke-width: 0.6;
}

.atom-e-val {
  fill: var(--accent);
  stroke: var(--ink);
  stroke-width: 0.6;
}

.atom-nucleus {
  fill: var(--nucleus);
}

.atom-nuc-label {
  fill: #ffffff;
  font-family: var(--mono);
  font-weight: 600;
}

/* SVG geometry attributes cannot take var() — a circle written as
   r="var(--dia-r-*)" fails attribute parsing and collapses to r=0.
   The CSS r property DOES accept var() and wins over the attribute.
   Tokens are unitless; in SVG, 1px = 1 user unit. (Same fix as
   components.css, commit 0b98f03 — this file doesn't load that.) */
circle[r="var(--dia-r-particle)"] { r: calc(var(--dia-r-particle) * 1px); }
circle[r="var(--dia-r-atom-sm)"] { r: calc(var(--dia-r-atom-sm) * 1px); }
circle[r="var(--dia-r-atom)"] { r: calc(var(--dia-r-atom) * 1px); }

.d-particle {
  stroke: var(--ink);
  stroke-width: 1.2;
}

.d-metal {
  stroke: var(--ink);
  stroke-width: 1.2;
}

.d-shell {
  fill: none;
  stroke: var(--shell);
  stroke-width: 0.8;
}

.d-nuc {
  fill: var(--nucleus);
}

.d-nuc-t {
  fill: #fff;
  font-family: var(--mono);
  font-weight: 600;
  font-size: 9px;
}

.d-frame {
  fill: none;
  stroke: var(--ink-mute);
  stroke-width: 1.5;
  stroke-dasharray: 6 4;
}

.d-wall {
  fill: none;
  stroke: var(--ink);
  stroke-width: 2.2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.d-water {
  fill: none;
  stroke: var(--water);
  stroke-width: 1.8;
}

.d-arrow {
  stroke: var(--ink);
  stroke-width: 1.6;
}

.d-label {
  font-family: var(--display);
  font-weight: 600;
  fill: var(--ink);
}

.d-sub {
  font-family: var(--mono);
  fill: var(--ink-mute);
}

/* Bracket wrapper labels for Lewis structures of ions */
.lewis-bracket {
  stroke: var(--ink);
  stroke-width: 1.5;
  fill: none;
}

.lewis-bracket-charge {
  font-family: var(--mono);
  font-weight: 600;
  font-size: 11px;
  fill: var(--ink);
}

/* Vertical stack modifiers and options styling */
.chips-grid.vertical {
  flex-direction: column;
  align-items: stretch;
}

.chips-grid.vertical .chip {
  text-align: center;
  font-weight: 600;
  padding: 0.5rem;
}

.options-stack {
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
  margin-top: 0.45rem;
}

.tab-panel {
  display: flex;
  flex-direction: column;
  gap: 1.2rem;
}

@media print {
  body {
    background: #ffffff;
    color: #000000;
  }
  .app-header,
  .sidebar,
  .preview-bar,
  .theme-toggle,
  .canvas-bg-grid {
    display: none !important;
  }
  .app-container {
    display: block;
    height: auto;
    width: 100%;
    margin: 0;
    padding: 0;
  }
  .preview-panel {
    background: none;
    border: none;
    box-shadow: none;
    width: 100%;
    height: auto;
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: center;
    align-items: center;
  }
  .canvas-area {
    background: none;
    border: none;
    box-shadow: none;
    padding: 0;
    margin: 0;
    width: 100%;
    height: auto;
    display: flex;
    justify-content: center;
    align-items: center;
  }
  .graphic-frame {
    box-shadow: none;
    border: none;
    background: #ffffff;
    max-width: 100%;
    max-height: 100%;
  }
}

/* Back Link pointing to home dashboard */
.back-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-family: var(--display);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--ink-soft);
  text-decoration: none;
  margin-right: 1rem;
  border: 1px solid var(--hair);
  border-radius: 6px;
  padding: 0.35rem 0.6rem;
  transition: all 0.15s ease;
  white-space: nowrap;
  flex-shrink: 0;
}
.back-link:hover {
  background: var(--paper-3);
  color: var(--ink);
  border-color: var(--ink-soft);
}

.action-btn {
  white-space: nowrap;
  flex-shrink: 0;
}

.action-btn svg, .back-link svg {
  flex-shrink: 0;
}

/* Responsive Mobile Rules */
@media (max-width: 860px) {
  body {
    height: auto;
    min-height: 100dvh;
    overflow-y: auto;
  }

  .app-header {
    height: auto;
    padding: 0.65rem 1rem;
    flex-wrap: wrap;
    gap: 0.5rem;
  }

  .app-title-group h1 {
    font-size: 1.05rem;
  }

  .header-actions {
    gap: 0.4rem;
  }

  .back-link {
    margin-right: 0;
    padding: 0.3rem 0.5rem;
    font-size: 0.78rem;
  }

  .app-container {
    display: flex;
    flex-direction: column;
    height: auto;
    overflow: visible;
  }

  .sidebar {
    order: 2;
    width: 100%;
    border-right: none;
    border-top: 1px solid var(--hair);
  }

  .preview-panel {
    order: 1;
    width: 100%;
    position: sticky;
    top: 0;
    z-index: 5;
    background: var(--paper);
    border-bottom: 1px solid var(--hair);
  }

  .preview-bar {
    height: auto;
    padding: 0.5rem 1rem;
    flex-wrap: nowrap;
    gap: 0.5rem;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
  }

  .preview-actions {
    overflow-x: auto;
    flex-wrap: nowrap;
    padding-bottom: 2px;
  }

  .canvas-area {
    padding: 1rem;
    min-height: 260px;
    max-height: 420px;
  }

  .graphic-frame {
    padding: 1rem;
    min-width: 0;
    width: 100%;
  }

  .builder-row {
    grid-template-columns: 1fr 1fr;
    gap: 0.4rem;
  }
}

@media (max-width: 520px) {
  .back-link-label {
    display: none;
  }
  .back-link {
    padding: 0.35rem;
  }
  .app-title-group span {
    display: none;
  }
}