/* ============================================================
   DEMO CSS – Interactive Demo Page Styles
   ============================================================ */

/* ─── Demo Layout ─── */
.demo-layout {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: var(--sp-6);
  align-items: start;
  margin-top: var(--sp-8);
}

/* ─── Step Sidebar ─── */
.demo-steps-sidebar {
  position: sticky;
  top: calc(var(--nav-height) + var(--sp-6));
  background: var(--bg-glass);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: var(--sp-5);
  backdrop-filter: blur(16px);
}

.demo-steps-title {
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--text-muted);
  margin-bottom: var(--sp-4);
  padding-bottom: var(--sp-3);
  border-bottom: 1px solid var(--border);
}

.demo-step-item {
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  padding: var(--sp-3);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
  margin-bottom: var(--sp-1);
  position: relative;
}

.demo-step-item:hover { background: rgba(255,255,255,0.04); }
.demo-step-item.active { background: rgba(6,182,212,0.08); }

.demo-step-item::before {
  content: '';
  position: absolute;
  left: -1px;
  top: 25%; bottom: 25%;
  width: 3px;
  border-radius: 0 2px 2px 0;
  background: var(--cyan);
  opacity: 0;
  transition: opacity var(--transition-fast);
}

.demo-step-item.active::before { opacity: 1; }

.demo-step-num {
  width: 28px; height: 28px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.75rem;
  font-weight: 700;
  font-family: var(--font-mono);
  flex-shrink: 0;
  border: 2px solid var(--border);
  background: var(--bg-surface);
  color: var(--text-muted);
  transition: all var(--transition-base);
}

.demo-step-item.active .demo-step-num {
  border-color: var(--cyan);
  color: var(--cyan);
  background: rgba(6,182,212,0.12);
  box-shadow: 0 0 12px rgba(6,182,212,0.3);
}

.demo-step-item.done .demo-step-num {
  border-color: var(--green);
  color: var(--green);
  background: rgba(16,185,129,0.12);
}

.demo-step-label {
  font-size: 0.825rem;
  font-weight: 500;
  color: var(--text-muted);
  transition: color var(--transition-fast);
}

.demo-step-item.active .demo-step-label { color: var(--text-primary); }
.demo-step-item.done  .demo-step-label { color: var(--green); }

.demo-connector {
  width: 2px;
  height: 16px;
  background: var(--border);
  margin: 2px 0 2px calc(14px + var(--sp-3));
  border-radius: 1px;
  transition: background var(--transition-base);
}

.demo-connector.done { background: var(--green); opacity: 0.5; }

/* ─── Demo Main Panel ─── */
.demo-panel {
  background: var(--bg-glass);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  overflow: hidden;
  backdrop-filter: blur(16px);
}

.demo-panel-header {
  padding: var(--sp-5) var(--sp-6);
  border-bottom: 1px solid var(--border);
  background: rgba(255,255,255,0.02);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--sp-4);
}

.demo-panel-title {
  display: flex;
  align-items: center;
  gap: var(--sp-3);
}

.demo-panel-title h3 {
  font-size: 1.1rem;
  font-weight: 700;
}

.demo-panel-body { padding: var(--sp-6); }

/* ─── Step Views ─── */
.step-view { display: none; }
.step-view.active { display: block; animation: fadeIn 0.3s ease; }

/* ─── Step 1: Input ─── */
.input-options {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--sp-4);
  margin-bottom: var(--sp-6);
}

.input-option {
  padding: var(--sp-4);
  border: 2px solid var(--border);
  border-radius: var(--radius-lg);
  cursor: pointer;
  transition: all var(--transition-base);
  text-align: center;
  background: var(--bg-surface);
}

.input-option:hover { border-color: rgba(6,182,212,0.3); }
.input-option.selected { border-color: var(--cyan); background: rgba(6,182,212,0.06); }
.input-option-icon { font-size: 2rem; margin-bottom: var(--sp-2); }
.input-option-label { font-size: 0.875rem; font-weight: 600; }

.demo-textarea {
  width: 100%;
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  padding: var(--sp-4);
  font-family: var(--font-sans);
  font-size: 0.9rem;
  resize: vertical;
  min-height: 120px;
  transition: border-color var(--transition-fast);
  outline: none;
}

.demo-textarea:focus { border-color: var(--cyan); box-shadow: 0 0 0 3px rgba(6,182,212,0.1); }

.file-drop-zone {
  border: 2px dashed var(--border);
  border-radius: var(--radius-lg);
  padding: var(--sp-10);
  text-align: center;
  cursor: pointer;
  transition: all var(--transition-base);
  background: rgba(255,255,255,0.01);
}

.file-drop-zone:hover,
.file-drop-zone.drag-over {
  border-color: var(--cyan);
  background: rgba(6,182,212,0.04);
}

.file-drop-icon { font-size: 2.5rem; margin-bottom: var(--sp-3); }
.file-drop-zone p { margin-bottom: var(--sp-3); }
.file-drop-zone input[type="file"] { display: none; }

.file-selected {
  background: rgba(16,185,129,0.06);
  border: 1px solid rgba(16,185,129,0.2);
  border-radius: var(--radius-md);
  padding: var(--sp-4);
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  margin-top: var(--sp-4);
}

.file-selected-icon { font-size: 1.5rem; }
.file-name { font-weight: 500; font-size: 0.9rem; }
.file-size { font-size: 0.8rem; color: var(--text-muted); font-family: var(--font-mono); }

/* ─── Step 2: Key Exchange ─── */
.key-exchange-cols {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: var(--sp-4);
  align-items: start;
  margin-bottom: var(--sp-6);
}

.party-col {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.party-col-header {
  padding: var(--sp-4) var(--sp-5);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: var(--sp-3);
}

.party-avatar {
  width: 36px; height: 36px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  font-weight: 700;
  font-family: var(--font-mono);
}

.avatar-sender   { background: rgba(6,182,212,0.15);  color: var(--cyan);         border: 2px solid rgba(6,182,212,0.3); }
.avatar-receiver { background: rgba(139,92,246,0.15); color: var(--purple-light); border: 2px solid rgba(139,92,246,0.3); }

.party-name { font-weight: 700; font-size: 0.95rem; }
.party-role { font-size: 0.75rem; color: var(--text-muted); }

.party-col-body { padding: var(--sp-4) var(--sp-5); }

.key-field {
  margin-bottom: var(--sp-4);
}

.key-field-label {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: var(--sp-1);
}

.key-field-value {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--cyan-light);
  background: #0a1628;
  border: 1px solid rgba(6,182,212,0.12);
  border-radius: var(--radius-sm);
  padding: var(--sp-2) var(--sp-3);
  word-break: break-all;
  line-height: 1.6;
  min-height: 38px;
  display: flex;
  align-items: center;
  transition: all var(--transition-base);
}

.key-field-value.empty { color: var(--text-muted); font-style: italic; }
.key-field-value.purple-val { color: var(--purple-light); background: #0d0a1e; border-color: rgba(139,92,246,0.12); }
.key-field-value.green-val  { color: var(--green); background: #071612; border-color: rgba(16,185,129,0.12); }

.exchange-mid {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--sp-4);
  min-width: 80px;
  padding-top: var(--sp-10);
}

.exchange-arrow {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--sp-1);
}

.arrow-line {
  width: 2px;
  height: 40px;
  background: linear-gradient(to bottom, var(--cyan), var(--purple));
  opacity: 0.5;
  position: relative;
}

.arrow-line::before {
  content: '⟵  ⟶';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 0.7rem;
  color: var(--text-muted);
  white-space: nowrap;
  background: var(--bg-primary);
  padding: 2px 4px;
  border-radius: 4px;
}

.exchange-icon { font-size: 1.5rem; }

/* ─── LWE Matrix Display ─── */
.lwe-section {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--sp-5);
  margin-bottom: var(--sp-4);
}

.lwe-section-title {
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--cyan);
  margin-bottom: var(--sp-4);
  display: flex;
  align-items: center;
  gap: var(--sp-2);
}

.matrix-wrap {
  display: flex;
  align-items: center;
  gap: var(--sp-4);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  overflow-x: auto;
  padding-bottom: var(--sp-2);
}

.matrix-label {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-muted);
}

.demo-matrix {
  display: inline-flex;
  align-items: stretch;
  gap: 2px;
}

.demo-matrix-bracket {
  display: flex;
  flex-direction: column;
  justify-content: stretch;
}

.demo-matrix-bracket span {
  flex: 1;
  width: 10px;
  border: 2px solid var(--cyan);
  opacity: 0.5;
}

.demo-matrix-bracket.left span:first-child  { border-right: none; border-bottom: none; border-radius: 3px 0 0 0; }
.demo-matrix-bracket.left span:last-child   { border-right: none; border-top: none; border-radius: 0 0 0 3px; }
.demo-matrix-bracket.left span:not(:first-child):not(:last-child) { border-right: none; border-top: none; border-bottom: none; }
.demo-matrix-bracket.right span:first-child  { border-left: none; border-bottom: none; border-radius: 0 3px 0 0; }
.demo-matrix-bracket.right span:last-child   { border-left: none; border-top: none; border-radius: 0 0 3px 0; }
.demo-matrix-bracket.right span:not(:first-child):not(:last-child) { border-left: none; border-top: none; border-bottom: none; }

.demo-matrix-cells {
  display: grid;
  gap: var(--sp-2) var(--sp-4);
  padding: var(--sp-2) var(--sp-3);
}

.demo-matrix-cell {
  text-align: right;
  color: var(--text-code);
  min-width: 28px;
}

.matrix-op {
  font-size: 1.1rem;
  color: var(--text-muted);
  padding: 0 var(--sp-1);
}

.matrix-result {
  color: var(--cyan-light) !important;
}

/* ─── Hybrid Key Section ─── */
.hybrid-key-display {
  background: linear-gradient(135deg, rgba(6,182,212,0.06), rgba(139,92,246,0.06));
  border: 1px solid;
  border-image: linear-gradient(135deg, rgba(6,182,212,0.4), rgba(139,92,246,0.4)) 1;
  border-radius: var(--radius-lg);
  padding: var(--sp-5);
  text-align: center;
}

.hybrid-key-label {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-bottom: var(--sp-3);
  background: linear-gradient(90deg, var(--cyan), var(--purple));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hybrid-key-value {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-primary);
  word-break: break-all;
  line-height: 1.8;
  letter-spacing: 0.05em;
}

.hybrid-key-value span {
  padding: 2px 4px;
  border-radius: 3px;
}
.hybrid-key-value .k-cyan   { color: var(--cyan-light);   background: rgba(6,182,212,0.1); }
.hybrid-key-value .k-purple { color: var(--purple-light); background: rgba(139,92,246,0.1); }

/* ─── Step 3: Encryption ─── */
.encrypt-flow {
  display: flex;
  flex-direction: column;
  gap: var(--sp-4);
}

.encrypt-step {
  display: flex;
  gap: var(--sp-4);
  align-items: flex-start;
}

.encrypt-step-dot {
  width: 10px; height: 10px;
  border-radius: 50%;
  flex-shrink: 0;
  margin-top: 5px;
}

.encrypt-step-dot-cyan   { background: var(--cyan);   box-shadow: 0 0 8px var(--cyan); }
.encrypt-step-dot-purple { background: var(--purple); box-shadow: 0 0 8px var(--purple); }
.encrypt-step-dot-green  { background: var(--green);  box-shadow: 0 0 8px var(--green); }

.encrypt-step-content h5 { margin-bottom: var(--sp-1); font-size: 0.9rem; }
.encrypt-step-content p  { font-size: 0.85rem; margin-bottom: var(--sp-2); }

.cipher-preview {
  background: #050b15;
  border: 1px solid rgba(6,182,212,0.12);
  border-radius: var(--radius-md);
  padding: var(--sp-3) var(--sp-4);
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: rgba(6,182,212,0.7);
  word-break: break-all;
  line-height: 1.7;
  max-height: 120px;
  overflow-y: auto;
  position: relative;
}

.cipher-preview::before {
  content: 'CIPHERTEXT';
  position: absolute;
  top: var(--sp-2); right: var(--sp-3);
  font-size: 0.6rem;
  letter-spacing: 0.15em;
  color: var(--text-muted);
}

/* ─── Step 4: Download ─── */
.download-card {
  text-align: center;
  padding: var(--sp-10);
  background: var(--bg-surface);
  border: 2px dashed rgba(16,185,129,0.3);
  border-radius: var(--radius-xl);
}

.download-icon {
  font-size: 3.5rem;
  margin-bottom: var(--sp-4);
  display: block;
}

.download-card h4 { margin-bottom: var(--sp-2); }
.download-card p  { margin-bottom: var(--sp-6); }

/* ─── Step 5: Decrypt ─── */
.decrypt-panel {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--sp-6);
}

.decrypt-upload-zone {
  border: 2px dashed rgba(139,92,246,0.3);
  border-radius: var(--radius-lg);
  padding: var(--sp-8);
  text-align: center;
  cursor: pointer;
  transition: all var(--transition-base);
  background: rgba(139,92,246,0.03);
}

.decrypt-upload-zone:hover {
  border-color: var(--purple);
  background: rgba(139,92,246,0.06);
}

.decrypt-result {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--sp-5);
  min-height: 200px;
  display: flex;
  flex-direction: column;
}

.decrypt-result-label {
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  margin-bottom: var(--sp-3);
}

.decrypt-result-content {
  flex: 1;
  font-size: 0.9rem;
  color: var(--text-secondary);
  white-space: pre-wrap;
  word-break: break-word;
  overflow-y: auto;
  font-family: var(--font-sans);
}

.decrypt-result-content.success { color: var(--green); }
.decrypt-result-content.error   { color: var(--red); }

/* ─── Computation Log ─── */
.computation-log {
  background: #020810;
  border: 1px solid rgba(6,182,212,0.1);
  border-radius: var(--radius-lg);
  padding: var(--sp-4);
  max-height: 300px;
  overflow-y: auto;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  margin-top: var(--sp-6);
}

.log-entry {
  display: flex;
  gap: var(--sp-3);
  margin-bottom: var(--sp-2);
  animation: fadeIn 0.3s ease;
}

.log-ts {
  color: var(--text-muted);
  flex-shrink: 0;
  font-size: 0.72rem;
  margin-top: 2px;
}

.log-msg { line-height: 1.5; }
.log-msg.info    { color: var(--text-secondary); }
.log-msg.success { color: var(--green); }
.log-msg.key     { color: var(--cyan); }
.log-msg.lwe     { color: var(--purple-light); }
.log-msg.error   { color: var(--red); }

/* ─── Noise slider ─── */
.noise-control {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--sp-4) var(--sp-5);
  margin-top: var(--sp-4);
}

.noise-control-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--sp-3);
}

.noise-label { font-size: 0.875rem; font-weight: 600; }
.noise-value {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--cyan);
  background: rgba(6,182,212,0.1);
  padding: 2px 10px;
  border-radius: var(--radius-full);
}

input[type="range"] {
  width: 100%;
  -webkit-appearance: none;
  appearance: none;
  height: 4px;
  border-radius: 4px;
  background: var(--bg-elevated);
  outline: none;
  cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 18px; height: 18px;
  border-radius: 50%;
  background: var(--cyan);
  box-shadow: 0 0 8px var(--cyan-glow);
  cursor: pointer;
  transition: transform var(--transition-fast);
}

input[type="range"]::-webkit-slider-thumb:hover { transform: scale(1.2); }

.noise-warning {
  margin-top: var(--sp-3);
  padding: var(--sp-3) var(--sp-4);
  background: rgba(239,68,68,0.08);
  border: 1px solid rgba(239,68,68,0.2);
  border-radius: var(--radius-sm);
  font-size: 0.8rem;
  color: var(--red);
  display: none;
}

.noise-warning.show { display: block; }

/* ─── Demo Navigation ─── */
.demo-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: var(--sp-5);
  margin-top: var(--sp-5);
  border-top: 1px solid var(--border);
}

.demo-quick-run {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: var(--sp-5) var(--sp-6);
  margin-bottom: var(--sp-6);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--sp-4);
}

.demo-quick-run p { margin: 0; font-size: 0.9rem; }
.demo-quick-run h4 { margin-bottom: var(--sp-1); }

/* ─── Responsive demo ─── */
@media (max-width: 1100px) {
  .demo-layout { grid-template-columns: 1fr; }
  .demo-steps-sidebar { position: static; }
  .demo-steps-sidebar { display: flex; overflow-x: auto; gap: var(--sp-2); flex-direction: row; padding: var(--sp-4); }
  .demo-step-item { flex-direction: column; text-align: center; min-width: 80px; }
  .demo-connector { display: none; }
  .demo-step-item::before { display: none; }
}

@media (max-width: 768px) {
  .key-exchange-cols { grid-template-columns: 1fr; }
  .exchange-mid { display: none; }
  .decrypt-panel { grid-template-columns: 1fr; }
  .input-options { grid-template-columns: 1fr; }
}