* {
  box-sizing: border-box;
}

:root {
  --bg: #0a0a0a;
  --border: 1px solid rgba(255, 255, 255, 0.12);
  --text: rgba(255, 255, 255, 0.9);
  --muted: rgba(255, 255, 255, 0.5);
  --font: "IBM Plex Mono", "SF Mono", "Consolas", monospace;
  --base: 15px;
}

html, body {
  margin: 0;
  width: 100vw;
  height: 100vh;
  overflow: hidden;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: var(--base);
  -webkit-font-smoothing: antialiased;
}

.header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.85rem 1.15rem;
  border-bottom: var(--border);
  flex-shrink: 0;
}

.header h1 {
  margin: 0;
  font-size: 1.1rem;
  font-weight: 400;
  letter-spacing: 0.05em;
}

.btn {
  background: transparent;
  color: var(--text);
  border: var(--border);
  padding: 0.5rem 0.9rem;
  font-family: inherit;
  font-size: 0.9rem;
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
}

.btn:hover {
  background: rgba(255, 255, 255, 0.06);
}

.btn-ghost:hover {
  background: rgba(255, 255, 255, 0.04);
}

.main {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 0;
  height: calc(100vh - 3.2rem - 3rem);
  border-bottom: var(--border);
}

.panel {
  border-right: var(--border);
  padding: 0.85rem 1.15rem;
  display: flex;
  flex-direction: column;
  min-height: 0;
}

.panel:last-child {
  border-right: none;
}

.panel h2 {
  margin: 0 0 0.6rem 0;
  font-size: 0.8rem;
  font-weight: 400;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--muted);
}

/* Third column: Instructions on top, Output on bottom; each block scrolls only when content overflows */
.panel-right {
  flex-direction: column;
  padding: 0;
  gap: 0;
}

.panel-right .panel-block {
  display: flex;
  flex-direction: column;
  min-height: 0;
  padding: 0.85rem 1.15rem;
  border-bottom: var(--border);
}

.panel-right .panel-block:first-child {
  flex: 0 1 30%;
}

.panel-right .panel-block:nth-child(2) {
  flex: 0 1 30%;
  border-bottom: var(--border);
}

.panel-right .panel-block:last-child {
  border-bottom: none;
  flex: 1 1 40%;
}

.zk-controls {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  margin-bottom: 0.6rem;
}

.zk-status {
  font-size: 0.85rem;
  color: var(--muted);
}

.witness-view {
  font-size: 0.82rem;
  background: rgba(255, 255, 255, 0.02);
  border: var(--border);
  flex: 1;
}

.proof-cert {
  padding: 1rem;
}

.cert-header {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: #88c0d0;
  margin-bottom: 0.8rem;
  border-bottom: 1px solid rgba(136, 192, 208, 0.2);
  padding-bottom: 0.4rem;
}

.cert-row {
  display: flex;
  justify-content: space-between;
  margin-bottom: 0.4rem;
  font-family: var(--font);
}

.cert-row span:first-child {
  color: var(--muted);
}

.cert-section-title {
  font-size: 0.75rem;
  color: var(--muted);
  margin: 1rem 0 0.5rem 0;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.muted {
  color: var(--muted) !important;
}

.panel-right .panel-block h2 {
  flex-shrink: 0;
}

/* Scrollable areas: overflow only when content exceeds size */
.scrollable {
  overflow: auto;
  min-height: 0;
}

.instr-history.scrollable {
  flex: 1;
  font-size: 0.88rem;
  color: var(--muted);
  line-height: 1.55;
}

.output-content {
  flex: 1;
  margin: 0;
  min-height: 0;
  font-size: 0.95rem;
  line-height: 1.5;
  color: var(--text);
  white-space: pre-wrap;
  word-break: break-all;
}

/* Themed scrollbars: thin, dark, only when needed */
.scrollable::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}

.scrollable::-webkit-scrollbar-track {
  background: transparent;
}

.scrollable::-webkit-scrollbar-thumb {
  background: rgba(255, 255, 255, 0.15);
  border-radius: 3px;
}

.scrollable::-webkit-scrollbar-thumb:hover {
  background: rgba(255, 255, 255, 0.22);
}

.scrollable::-webkit-scrollbar-corner {
  background: transparent;
}

/* Firefox */
.scrollable {
  scrollbar-width: thin;
  scrollbar-color: rgba(255, 255, 255, 0.15) transparent;
}

.cpu-grid {
  display: grid;
  gap: 0.2rem;
  overflow: auto;
  min-height: 0;
}

.cpu-grid::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}

.cpu-grid::-webkit-scrollbar-track {
  background: transparent;
}

.cpu-grid::-webkit-scrollbar-thumb {
  background: rgba(255, 255, 255, 0.15);
  border-radius: 3px;
}

.cpu-grid::-webkit-scrollbar-thumb:hover {
  background: rgba(255, 255, 255, 0.22);
}

.cpu-grid {
  scrollbar-width: thin;
  scrollbar-color: rgba(255, 255, 255, 0.15) transparent;
}

.cpu-row {
  display: grid;
  grid-template-columns: 3.2rem 1fr;
  gap: 0.6rem;
}

.label {
  color: var(--muted);
}

.value {
  word-break: break-all;
  font-size: 0.9rem;
}

.regs {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.2rem 1.2rem;
  margin-top: 0.3rem;
}

.regs .cpu-row {
  grid-template-columns: 2.2rem 1fr;
}

.mem-view {
  flex: 1;
  overflow: auto;
  min-height: 0;
  font-size: 0.88rem;
  line-height: 1.45;
  color: var(--muted);
}

.mem-view::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}

.mem-view::-webkit-scrollbar-track {
  background: transparent;
}

.mem-view::-webkit-scrollbar-thumb {
  background: rgba(255, 255, 255, 0.15);
  border-radius: 3px;
}

.mem-view::-webkit-scrollbar-thumb:hover {
  background: rgba(255, 255, 255, 0.22);
}

.mem-view {
  scrollbar-width: thin;
  scrollbar-color: rgba(255, 255, 255, 0.15) transparent;
}

.mem-line {
  display: flex;
  gap: 0.6rem;
}

.mem-addr {
  flex-shrink: 0;
  width: 9ch;
}

.mem-line-highlight {
  background: rgba(255, 255, 255, 0.04);
}

.instr-current {
  flex-shrink: 0;
  padding: 0.5rem 0;
  border-bottom: var(--border);
  margin-bottom: 0.6rem;
  font-size: 0.95rem;
}

.controls {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.5rem 1.15rem;
  border-top: var(--border);
  flex-shrink: 0;
}

.status {
  margin-left: 0.6rem;
  font-size: 0.88rem;
  color: var(--muted);
}

.overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.7);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
}

.overlay[hidden] {
  display: none;
}

.modal {
  background: var(--bg);
  border: var(--border);
  padding: 1.4rem;
  width: 92%;
  max-width: 560px;
}

.modal h2 {
  margin: 0 0 0.85rem 0;
  font-size: 1rem;
  font-weight: 400;
}

.hint {
  font-size: 0.8rem;
  color: var(--muted);
  margin: 0 0 0.85rem 0;
  line-height: 1.5;
}

.hint code {
  font-size: 0.75rem;
  padding: 0.12rem 0.25rem;
  background: rgba(255, 255, 255, 0.06);
}

.modal textarea {
  width: 100%;
  padding: 0.7rem;
  margin-bottom: 0.85rem;
  background: transparent;
  border: var(--border);
  color: var(--text);
  font-family: var(--font);
  font-size: 0.88rem;
  resize: vertical;
  min-height: 140px;
}

.modal textarea::placeholder {
  color: var(--muted);
}

.modal textarea:focus {
  outline: none;
  border-color: rgba(255, 255, 255, 0.25);
}

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

.error {
  margin-top: 0.6rem;
  font-size: 0.88rem;
  color: #e07070;
}

.error:empty {
  display: none;
}