/* ==========================================================================
   Splunk Infrastructure Sizing Calculator
   Aesthetic: dark "infrastructure console / blueprint" - engineered, credible,
   monospace display identity, blueprint-grid backdrop, color-coded storage
   tiers. Fully self-contained (no web fonts) so it renders identically from
   file:// while offline. Motion is limited to hover / focus / button feedback
   because results re-render live on every keystroke.
   ========================================================================== */

:root {
  --font-mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, "Cascadia Code",
    "JetBrains Mono", "Roboto Mono", Consolas, monospace;
  --font-sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue",
    Arial, sans-serif;

  --bg: #0a0e14;
  --panel: #111721;
  --panel-2: #161d29;
  --panel-3: #1b2431;
  --ink: #e7eef6;
  --ink-dim: #b9c4d1;
  --muted: #7d8b9c;
  --faint: #4d5a6b;
  --border: #212c3a;
  --border-bright: #2d3b4d;

  --accent: #ff3d9e;      /* Splunk pink */
  --accent-bright: #ff5caf;
  /* Lighter pink used specifically for button fills. */
  --btn-top: #ff8cc6;
  --btn-bottom: #ff63b3;
  --accent-ink: #1a0d06;

  --tier-high: #ff3d9e;   /* hot - SSD */
  --tier-medium: #4aa3ff; /* cold */
  --tier-low: #7f8da0;

  --vm: #35d29a;
  --physical: #ff3d9e;

  --warn-bg: rgba(230, 168, 45, 0.10);
  --warn-border: #b7891f;
  --warn-ink: #f0c469;
  --error-bg: rgba(224, 78, 54, 0.11);
  --error-border: #b9422d;
  --error-ink: #ff8f78;

  --radius: 12px;
  --radius-sm: 8px;
  --shadow: 0 18px 40px -24px rgba(0, 0, 0, 0.9);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.55;
  color: var(--ink);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

/* --- Blueprint backdrop --------------------------------------------------- */
.grid-backdrop {
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background-color: var(--bg);
  background-image:
    radial-gradient(900px 520px at 78% -8%, rgba(255, 61, 158, 0.14), transparent 60%),
    radial-gradient(760px 460px at 4% 2%, rgba(74, 163, 255, 0.08), transparent 55%),
    linear-gradient(var(--border) 1px, transparent 1px),
    linear-gradient(90deg, var(--border) 1px, transparent 1px);
  background-size: 100% 100%, 100% 100%, 46px 46px, 46px 46px;
  background-position: 0 0, 0 0, -1px -1px, -1px -1px;
  opacity: 0.9;
  mask-image: linear-gradient(180deg, #000 0%, #000 62%, transparent 100%);
  -webkit-mask-image: linear-gradient(180deg, #000 0%, #000 62%, transparent 100%);
}

/* --- Shared site nav -------------------------------------------------------- */
.site-nav {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  max-width: 1240px;
  margin: 0 auto;
  padding: 1.1rem 2rem 0;
}
.nav-link {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  text-decoration: none;
  color: var(--muted);
  padding: 0.4rem 0;
  border-bottom: 2px solid transparent;
  transition: color 0.15s ease, border-color 0.15s ease;
}
.nav-link:hover { color: var(--ink-dim); }
.nav-link.active {
  color: var(--accent-bright);
  border-bottom-color: var(--accent);
}
.nav-link:focus-visible {
  outline: none;
  box-shadow: 0 0 0 3px rgba(255, 61, 158, 0.35);
  border-radius: 3px;
}
@media (max-width: 880px) {
  .site-nav { padding: 1rem 1.25rem 0; }
}

/* --- Header --------------------------------------------------------------- */
.site-header {
  padding: 3.4rem 2rem 2rem;
}
.site-header__inner {
  max-width: 1240px;
  margin: 0 auto;
}
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  margin: 0 0 1rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.34em;
  text-transform: uppercase;
  color: var(--accent-bright);
}
.eyebrow__dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 4px rgba(255, 61, 158, 0.18), 0 0 14px 2px rgba(255, 61, 158, 0.6);
  animation: pulse 2.6s ease-in-out infinite;
}
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.45; }
}
.site-header h1 {
  margin: 0;
  font-family: var(--font-mono);
  font-size: clamp(1.9rem, 4.4vw, 3.1rem);
  font-weight: 600;
  line-height: 1.04;
  letter-spacing: -0.02em;
  color: var(--ink);
}
.tagline {
  margin: 0.9rem 0 0;
  color: var(--muted);
  font-size: 1.02rem;
}

/* --- Layout --------------------------------------------------------------- */
.layout {
  display: grid;
  grid-template-columns: minmax(320px, 400px) 1fr;
  gap: 1.75rem;
  max-width: 1240px;
  margin: 0 auto;
  padding: 1.25rem 2rem 3rem;
  align-items: start;
}

/* --- Inputs panel --------------------------------------------------------- */
.inputs-panel {
  position: sticky;
  top: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}
.inputs-panel fieldset {
  position: relative;
  margin: 0;
  padding: 1.15rem 1.25rem 1.3rem;
  background: linear-gradient(180deg, var(--panel-2), var(--panel));
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}
.inputs-panel legend {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0;
  margin-left: -0.1rem;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-dim);
}
.legend-idx {
  font-size: 0.68rem;
  color: var(--accent-bright);
  border: 1px solid rgba(255, 61, 158, 0.4);
  border-radius: 5px;
  padding: 0.12rem 0.36rem;
  background: rgba(255, 61, 158, 0.08);
}

/* Field (number inputs) */
.field {
  display: block;
  margin-top: 1rem;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--ink-dim);
}
.field .unit {
  float: right;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--faint);
  background: var(--panel-3);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 0.12rem 0.55rem;
}
.field input[type="number"] {
  clear: both;
  display: block;
  width: 100%;
  margin-top: 0.5rem;
  padding: 0.62rem 0.75rem;
  font-family: var(--font-mono);
  font-size: 1.05rem;
  color: var(--ink);
  background: var(--bg);
  border: 1px solid var(--border-bright);
  border-radius: var(--radius-sm);
  transition: border-color 0.15s ease, box-shadow 0.15s ease, background 0.15s ease;
  -moz-appearance: textfield;
  appearance: textfield;
}
.field input[type="number"]::-webkit-outer-spin-button,
.field input[type="number"]::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}
.field input[type="number"]::placeholder { color: var(--faint); }
.field input[type="number"]:focus {
  outline: none;
  border-color: var(--accent);
  background: #0c1119;
  box-shadow: 0 0 0 3px rgba(255, 61, 158, 0.18);
}
.field input[type="number"]:disabled {
  background: var(--panel);
  color: var(--faint);
  border-color: var(--border);
  cursor: not-allowed;
  opacity: 0.65;
}
.inputs-panel small {
  display: block;
  margin-top: 0.5rem;
  font-size: 0.78rem;
  font-weight: 400;
  color: var(--muted);
}
#rf-sf-hint {
  margin-top: 0.85rem;
  padding: 0.45rem 0.65rem;
  border-left: 2px solid var(--accent);
  background: rgba(255, 61, 158, 0.07);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--ink-dim);
}
#rf-sf-hint[hidden] { display: none; }

.field-pair {
  display: flex;
  gap: 0.9rem;
}
.field-pair .field { flex: 1; min-width: 0; }

/* Segmented control (environment) */
.radio-row.segmented {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.4rem;
  margin-top: 1rem;
  padding: 0.3rem;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
}
.seg {
  position: relative;
  cursor: pointer;
}
.seg input { position: absolute; opacity: 0; inset: 0; cursor: pointer; }
.seg span {
  display: block;
  text-align: center;
  padding: 0.55rem 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  letter-spacing: 0.04em;
  color: var(--muted);
  border-radius: 6px;
  border: 1px solid transparent;
  transition: color 0.15s ease, background 0.15s ease, border-color 0.15s ease;
}
.seg:hover span { color: var(--ink-dim); }
.seg input:checked + span {
  color: var(--accent-ink);
  background: linear-gradient(180deg, var(--accent-bright), var(--accent));
  border-color: var(--accent-bright);
  font-weight: 600;
  box-shadow: 0 4px 14px -6px rgba(255, 61, 158, 0.7);
}
.seg input:focus-visible + span {
  box-shadow: 0 0 0 3px rgba(255, 61, 158, 0.35);
}

/* Toggle switch (e.g. Search Head Clustering) */
.toggle-field {
  display: grid;
  grid-template-columns: auto 1fr;
  align-items: center;
  column-gap: 0.6rem;
  margin-top: 0.9rem;
  cursor: pointer;
}
.toggle-field input { position: absolute; opacity: 0; width: 0; height: 0; }
.toggle-track {
  position: relative;
  width: 40px;
  height: 22px;
  border-radius: 999px;
  background: var(--panel-3);
  border: 1px solid var(--border-bright);
  transition: background 0.15s ease, border-color 0.15s ease;
}
.toggle-track::after {
  content: "";
  position: absolute;
  top: 2px;
  left: 2px;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--ink-dim);
  transition: transform 0.15s ease, background 0.15s ease;
}
.toggle-field input:checked + .toggle-track {
  background: linear-gradient(180deg, var(--accent-bright), var(--accent));
  border-color: var(--accent-bright);
}
.toggle-field input:checked + .toggle-track::after {
  transform: translateX(18px);
  background: var(--accent-ink);
}
.toggle-field input:focus-visible + .toggle-track {
  box-shadow: 0 0 0 3px rgba(255, 61, 158, 0.35);
}
.toggle-field input:disabled + .toggle-track { opacity: 0.45; }
.toggle-label { font-size: 0.92rem; color: var(--ink); }
.toggle-field small { grid-column: 2; color: var(--muted); }
.toggle-field input:disabled ~ .toggle-label { color: var(--muted); }

/* Usage radio stack */
.radio-stack {
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
  margin-top: 1rem;
}
.usage-opt {
  position: relative;
  display: flex;
  gap: 0.7rem;
  padding: 0.75rem 0.85rem;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: border-color 0.15s ease, background 0.15s ease;
}
.usage-opt:hover { border-color: var(--border-bright); }
.usage-opt input {
  margin: 0.2rem 0 0;
  accent-color: var(--accent);
  width: 1rem;
  height: 1rem;
  flex-shrink: 0;
}
.usage-opt:has(input:checked) {
  border-color: var(--accent);
  background: rgba(255, 61, 158, 0.07);
}
.usage-body {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
}
.usage-body strong {
  font-family: var(--font-mono);
  font-size: 0.86rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink);
}
.usage-opt:has(input:checked) .usage-body strong { color: var(--accent-bright); }
.usage-desc {
  font-size: 0.8rem;
  color: var(--muted);
  line-height: 1.4;
}

/* --- Results panel -------------------------------------------------------- */
.results-panel { min-width: 0; }
.results-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1.1rem;
  padding-bottom: 0.9rem;
  border-bottom: 1px solid var(--border);
}
.results-header h2 {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 1.1rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink);
}
.results-actions {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}
#copy-btn,
#download-json-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  letter-spacing: 0.04em;
  color: var(--accent-ink);
  background: linear-gradient(180deg, var(--btn-top), var(--btn-bottom));
  border: 1px solid var(--btn-top);
  border-radius: var(--radius-sm);
  padding: 0.55rem 1rem;
  cursor: pointer;
  white-space: nowrap;
  transition: transform 0.12s ease, box-shadow 0.15s ease, filter 0.15s ease;
  box-shadow: 0 6px 18px -8px rgba(255, 61, 158, 0.75);
}
#copy-btn::before {
  content: "";
  width: 12px;
  height: 12px;
  border: 1.6px solid currentColor;
  border-radius: 3px;
  box-shadow: 3px 3px 0 -1.6px var(--accent-ink), 3px 3px 0 currentColor;
}
#copy-btn:hover,
#download-json-btn:hover { filter: brightness(1.06); transform: translateY(-1px); }
#copy-btn:active,
#download-json-btn:active { transform: translateY(0); }
#copy-btn:focus-visible,
#download-json-btn:focus-visible { outline: none; box-shadow: 0 0 0 3px rgba(255, 61, 158, 0.4); }
#copy-btn[hidden],
#download-json-btn[hidden] { display: none; }

/* Banners */
.banner {
  position: relative;
  margin-bottom: 0.65rem;
  padding: 0.75rem 1rem 0.75rem 2.5rem;
  font-size: 0.9rem;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
}
.banner::before {
  position: absolute;
  left: 0.9rem;
  top: 0.72rem;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 0.95rem;
}
.banner-warning {
  background: var(--warn-bg);
  border-color: var(--warn-border);
  color: var(--warn-ink);
}
.banner-warning::before { content: "\26A0"; color: var(--warn-ink); }
.banner-error {
  background: var(--error-bg);
  border-color: var(--error-border);
  color: var(--error-ink);
}
.banner-error::before { content: "\2715"; color: var(--error-ink); }

/* Empty state */
#results-empty {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  margin: 2rem 0;
  padding: 1.5rem;
  color: var(--muted);
  font-size: 0.98rem;
  border: 1px dashed var(--border-bright);
  border-radius: var(--radius);
  background: rgba(255, 255, 255, 0.012);
}
#results-empty[hidden] { display: none; }
.empty-mark {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  border: 2px solid var(--faint);
  flex-shrink: 0;
}

/* Headline */
.headline {
  margin: 0 0 1.25rem;
  font-family: var(--font-mono);
  font-size: 1.15rem;
  color: var(--ink-dim);
}
.headline strong {
  font-size: 1.5rem;
  color: var(--accent-bright);
}

/* Machine cards */
.machine-card {
  position: relative;
  margin-bottom: 0.9rem;
  padding: 1.15rem 1.35rem 1.25rem;
  background: linear-gradient(180deg, var(--panel-2), var(--panel));
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  transition: border-color 0.15s ease, transform 0.15s ease;
}
.machine-card:hover {
  border-color: var(--border-bright);
  border-left-color: var(--accent-bright);
  transform: translateX(2px);
}
.machine-card header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 0.75rem;
  flex-wrap: wrap;
}
.machine-card h3 {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 1.02rem;
  font-weight: 600;
  letter-spacing: 0.01em;
  color: var(--ink);
}
.machine-card .count {
  color: var(--accent-bright);
  font-weight: 600;
}
.machine-type {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 0.2rem 0.6rem;
  border-radius: 999px;
  white-space: nowrap;
}
.type-vm {
  color: var(--vm);
  background: rgba(53, 210, 154, 0.12);
  border: 1px solid rgba(53, 210, 154, 0.4);
}
.type-physical {
  color: var(--physical);
  background: rgba(255, 61, 158, 0.12);
  border: 1px solid rgba(255, 61, 158, 0.45);
}
.spec-line {
  margin: 0.7rem 0 0.85rem;
  font-family: var(--font-mono);
  font-size: 0.95rem;
  color: var(--ink-dim);
  letter-spacing: 0.02em;
}
.drives {
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--border);
}
.drives li {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.75rem;
  flex-wrap: wrap;
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--border);
  font-size: 0.88rem;
}
.drives code {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--ink-dim);
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 5px;
  padding: 0.1rem 0.45rem;
}
.drives li strong {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  color: var(--ink);
  white-space: nowrap;
}
.note {
  margin: 0.75rem 0 0;
  padding-left: 0.85rem;
  border-left: 2px solid var(--border-bright);
  font-size: 0.82rem;
  color: var(--muted);
  font-style: italic;
}

/* Storage summary */
#compute-summary,
#storage-summary { margin-top: 1.75rem; }
#compute-summary h3,
#storage-summary h3 {
  margin: 0 0 0.9rem;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-dim);
}
.storage-table {
  width: 100%;
  border-collapse: collapse;
  background: linear-gradient(180deg, var(--panel-2), var(--panel));
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}
.storage-table td {
  padding: 0.72rem 1.1rem;
  border-bottom: 1px solid var(--border);
  font-size: 0.92rem;
  color: var(--ink-dim);
}
.storage-table td:first-child {
  position: relative;
  padding-left: 2rem;
}
.storage-table td:first-child::before {
  content: "";
  position: absolute;
  left: 1.1rem;
  top: 50%;
  transform: translateY(-50%);
  width: 9px;
  height: 9px;
  border-radius: 2px;
}
.storage-table tr:nth-child(1) td:first-child::before { background: var(--tier-high); box-shadow: 0 0 8px 0 rgba(255, 61, 158, 0.6); }
.storage-table tr:nth-child(2) td:first-child::before { background: var(--tier-medium); }
.storage-table tr:nth-child(3) td:first-child::before { background: var(--tier-low); }
.storage-table td:last-child {
  text-align: right;
  font-family: var(--font-mono);
  font-weight: 600;
  color: var(--ink);
}
.total-row td {
  border-bottom: none;
  background: rgba(255, 61, 158, 0.08);
  font-weight: 700;
  color: var(--ink);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-size: 0.86rem;
}
.total-row td:first-child::before { display: none; }
.total-row td:last-child { color: var(--accent-bright); font-size: 1rem; }
.per-day {
  margin: 0.85rem 0 0;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--muted);
}

/* --- Footer --------------------------------------------------------------- */
.site-footer {
  max-width: 1240px;
  margin: 0 auto;
  padding: 1.5rem 2rem 3rem;
  border-top: 1px solid var(--border);
}
.site-footer p {
  margin: 1.25rem 0 0;
  color: var(--faint);
  font-size: 0.82rem;
}

/* --- Responsive ----------------------------------------------------------- */
@media (max-width: 880px) {
  .layout {
    grid-template-columns: 1fr;
    gap: 1.5rem;
    padding: 1rem 1.25rem 2.5rem;
  }
  .inputs-panel { position: static; top: auto; }
  .site-header { padding: 2.4rem 1.25rem 1.5rem; }
  .site-footer { padding: 1.5rem 1.25rem 2.5rem; }
}
@media (max-width: 460px) {
  .results-header { flex-direction: column; align-items: flex-start; }
  .field-pair { flex-direction: column; gap: 0; }
}

/* --- Architecture page ---------------------------------------------------- */
.arch-layout {
  max-width: 1240px;
  margin: 0 auto;
  padding: 1.25rem 2rem 3rem;
}
.arch-toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1.1rem;
  padding-bottom: 0.9rem;
  border-bottom: 1px solid var(--border);
}
/* Show/hide toggles for diagram elements. */
.diagram-toggles {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 1rem;
  margin-left: auto;
}
.diagram-toggles[hidden] { display: none; }
.diagram-toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  cursor: pointer;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.02em;
  color: var(--ink-dim);
}
.diagram-toggle input { position: absolute; opacity: 0; width: 0; height: 0; }
.diagram-toggle .tg {
  position: relative;
  width: 34px;
  height: 18px;
  border-radius: 999px;
  background: var(--panel-3);
  border: 1px solid var(--border-bright);
  transition: background 0.15s ease, border-color 0.15s ease;
}
.diagram-toggle .tg::after {
  content: "";
  position: absolute;
  top: 2px;
  left: 2px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--ink-dim);
  transition: transform 0.15s ease, background 0.15s ease;
}
.diagram-toggle input:checked + .tg {
  background: linear-gradient(180deg, var(--btn-top), var(--btn-bottom));
  border-color: var(--btn-top);
}
.diagram-toggle input:checked + .tg::after { transform: translateX(16px); background: var(--accent-ink); }
.diagram-toggle input:focus-visible + .tg { box-shadow: 0 0 0 3px rgba(255, 61, 158, 0.35); }
/* All buttons across both pages share one look (Splunk-pink gradient). */
.upload-btn,
#download-png-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  letter-spacing: 0.04em;
  color: var(--accent-ink);
  background: linear-gradient(180deg, var(--btn-top), var(--btn-bottom));
  border: 1px solid var(--btn-top);
  border-radius: var(--radius-sm);
  padding: 0.55rem 1rem;
  cursor: pointer;
  white-space: nowrap;
  transition: transform 0.12s ease, box-shadow 0.15s ease, filter 0.15s ease;
  box-shadow: 0 6px 18px -8px rgba(255, 61, 158, 0.75);
}
.upload-btn:hover,
#download-png-btn:hover { filter: brightness(1.06); transform: translateY(-1px); }
.upload-btn:active,
#download-png-btn:active { transform: translateY(0); }
.upload-btn:focus-within,
#download-png-btn:focus-visible { outline: none; box-shadow: 0 0 0 3px rgba(255, 61, 158, 0.4); }
#download-png-btn[hidden] { display: none; }

#arch-empty {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  margin: 2rem 0;
  padding: 1.5rem;
  color: var(--muted);
  font-size: 0.98rem;
  border: 1px dashed var(--border-bright);
  border-radius: var(--radius);
  background: rgba(255, 255, 255, 0.012);
}
#arch-empty[hidden] { display: none; }

#arch-canvas-wrap {
  overflow-x: auto;
  border-radius: var(--radius);
}
#arch-svg {
  display: block;
  max-width: 100%;
  height: auto;
  margin: 0 auto;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg);
  box-shadow: var(--shadow);
}

@media (max-width: 880px) {
  .arch-layout { padding: 1rem 1.25rem 2.5rem; }
}

/* --- Reduced motion ------------------------------------------------------- */
@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; scroll-behavior: auto !important; }
}