/* ============================================================
   Memory Visualizer  —  modern dark with segment color coding
   ============================================================ */

:root {
  /* Surface palette */
  --bg:         #0f1115;
  --surface:    #181b22;
  --surface-2:  #1f242d;
  --border:     #2a2e38;
  --text:       #e6e8ee;
  --muted:      #8a93a6;
  --accent:     #6ea8ff;
  --accent-2:   #b78bff;

  /* Segment colors (consistent across all sections) */
  --c-text:     #4ea1ff;   /* .text       */
  --c-rodata:   #38bdf8;   /* .rodata     */
  --c-data:     #fb923c;   /* .data       */
  --c-bss:      #facc15;   /* .bss        */
  --c-heap:     #4ade80;   /* heap        */
  --c-mmap:     #a78bfa;   /* mmap region */
  --c-stack:    #f87171;   /* stack       */
  --c-kernel:   #6b7280;   /* kernel      */

  /* Semantic highlight colors */
  --c-canary:   #eab308;
  --c-retaddr:  #ec4899;
  --c-rbp:      #c084fc;
  --c-clobber:  #ef4444;
  --c-ok:       #22c55e;
  --c-warn:     #f59e0b;

  --mono: ui-monospace, "Cascadia Mono", "JetBrains Mono", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, system-ui, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.55;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
code, pre { font-family: var(--mono); }
code { background: var(--surface-2); padding: 1px 6px; border-radius: 4px; font-size: 0.9em; }
pre code { background: none; padding: 0; }
em { color: var(--accent); font-style: normal; }

/* ---------- Hero ---------- */
.hero {
  border-bottom: 1px solid var(--border);
  background: linear-gradient(180deg, #11141b 0%, var(--bg) 100%);
}
.hero-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 60px 32px 40px;
}
.hero h1 {
  font-size: 2.4rem;
  margin: 0 0 12px;
  letter-spacing: -0.02em;
}
.lede {
  font-size: 1.05rem;
  color: var(--muted);
  max-width: 780px;
}
.toc {
  margin-top: 24px;
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  font-family: var(--mono);
  font-size: 0.9rem;
}
.toc a {
  background: var(--surface);
  padding: 6px 12px;
  border-radius: 6px;
  border: 1px solid var(--border);
}

/* ---------- Section frame ---------- */
.scenario {
  max-width: 1200px;
  margin: 0 auto;
  padding: 56px 32px;
  border-bottom: 1px solid var(--border);
}
.scenario.danger .scenario-header h2::before {
  content: "\26A0  ";
  color: var(--c-clobber);
}
.scenario-header h2 {
  margin: 0 0 10px;
  font-size: 1.6rem;
  letter-spacing: -0.01em;
}
.scenario-header p {
  color: var(--muted);
  max-width: 820px;
  margin: 0;
}

.scenario-body.two-col {
  display: grid;
  grid-template-columns: 1.6fr 1fr;
  gap: 24px;
  margin-top: 28px;
}
@media (max-width: 960px) {
  .scenario-body.two-col { grid-template-columns: 1fr; }
}

.viz, .side-panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 18px;
}
.panel-block + .panel-block { margin-top: 18px; }
.panel-block h3 {
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
  margin: 0 0 10px;
}

.detail-box {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 12px;
  font-size: 0.92rem;
  min-height: 60px;
}
.muted { color: var(--muted); }

.notes {
  margin: 0;
  padding-left: 18px;
  font-size: 0.9rem;
  color: var(--muted);
}
.notes li { margin-bottom: 6px; }

.source-box {
  background: #0b0d12;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 12px 14px;
  margin-bottom: 14px;
  font-size: 0.88rem;
  overflow-x: auto;
}
.source-box pre { margin: 0; }

/* ---------- Controls ---------- */
.controls {
  display: flex;
  gap: 8px;
  align-items: center;
  margin-top: 14px;
}
.controls button {
  background: var(--surface-2);
  border: 1px solid var(--border);
  color: var(--text);
  font-family: var(--mono);
  font-size: 1rem;
  padding: 6px 12px;
  border-radius: 6px;
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s;
}
.controls button:hover:not(:disabled) { background: #262b35; border-color: var(--accent); }
.controls button:active:not(:disabled) { transform: translateY(1px); }
.controls button:disabled { opacity: 0.35; cursor: not-allowed; }
.step-indicator {
  margin-left: auto;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.85rem;
}

.step-status {
  margin-top: 14px;
  font-size: 0.9rem;
  color: var(--text);
  padding: 10px 12px;
  background: var(--surface-2);
  border-left: 3px solid var(--accent);
  border-radius: 4px;
  min-height: 40px;
}

/* ---------- Section 1: process layout ---------- */
#layout-viz {
  position: relative;
  display: grid;
  grid-template-columns: 130px 1fr;
  gap: 12px;
  height: 560px;
}
.addr-axis {
  position: relative;
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--muted);
}
.addr-tick {
  position: absolute;
  right: 0;
  white-space: nowrap;
}
.address-space {
  display: flex;
  flex-direction: column;
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: hidden;
}
.segment {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 16px;
  cursor: pointer;
  border-bottom: 1px solid rgba(0,0,0,0.4);
  position: relative;
  transition: filter 0.15s, transform 0.15s;
  color: #0b0d12;
  font-weight: 600;
  font-family: var(--mono);
  font-size: 0.85rem;
}
.segment:last-child { border-bottom: none; }
.segment:hover { filter: brightness(1.1); transform: translateX(4px); }
.segment.active { outline: 2px solid #fff; outline-offset: -2px; }
.segment .seg-arrow {
  font-size: 1.1rem;
  opacity: 0.8;
}

/* Segment colors */
.seg-kernel { background: var(--c-kernel); }
.seg-stack  { background: var(--c-stack); flex: 1.4; }
.seg-gap    { background: #2a2e38; color: var(--muted); flex: 1.2; cursor: default; }
.seg-mmap   { background: var(--c-mmap); }
.seg-heap   { background: var(--c-heap); flex: 1.2; }
.seg-bss    { background: var(--c-bss); }
.seg-data   { background: var(--c-data); }
.seg-rodata { background: var(--c-rodata); }
.seg-text   { background: var(--c-text); }

/* ---------- Section 2: CPU registers primer ---------- */

/* Lock both columns' size so the right panel stays exactly the same on every step.
   Width: by default fr columns have a min-content floor, so a long code line + its
   "◀ RIP (next instruction)" arrow can push the left column wider, squeezing the
   right. minmax(0, ...) removes that floor so columns stay at exact fr ratios.
   primer-viz gets overflow-x:auto so any overflowing code line scrolls within
   itself instead of warping the layout.
   Height: align-self:start stops the grid from stretching the right column;
   the status min-height also pins the left column so it doesn't jitter. */
#registers .scenario-body.two-col {
  grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr);
}
#registers .primer-viz { overflow-x: auto; }
#registers .side-panel { align-self: start; }
#registers .step-status { min-height: 6.5em; }

.primer-viz {
  background: #0b0d12;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 14px 22px;
  font-family: var(--mono);
  font-size: 0.92rem;
  line-height: 1.7;
  min-height: 260px;
}
.primer-col-h {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--muted);
  margin-bottom: 10px;
  padding-bottom: 4px;
  border-bottom: 1px solid var(--border);
}
.primer-code-col {
  padding-right: 110px;   /* room for RIP / RBP labels on the right */
}
.ps-code-line {
  padding: 3px 8px;
  border-radius: 3px;
  white-space: pre;
  color: var(--text);
  position: relative;
  border-left: 2px solid transparent;
  transition: background 0.2s, border-color 0.2s;
}
.ps-code-line.rip-line {
  background: rgba(110, 168, 255, 0.18);
  color: var(--accent);
}
.ps-code-line.rip-line::after {
  content: '  ◀ RIP (next instruction)';
  color: var(--accent);
  font-weight: 700;
  font-size: 0.78rem;
  letter-spacing: 0.02em;
}
.ps-code-line.rbp-line {
  border-left-color: var(--c-rbp);
  background: rgba(192, 132, 252, 0.07);
}
.ps-code-line.rbp-line::after {
  content: '  ◀ RBP (this frame is current)';
  color: var(--c-rbp);
  font-weight: 700;
  font-size: 0.78rem;
  letter-spacing: 0.02em;
}

.primer-regs {
  background: #0b0d12;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 8px;
  display: flex;
  flex-direction: column;
  gap: 2px;
}
.primer-reg {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 6px 8px;
  border-radius: 4px;
  cursor: help;
  transition: background 0.15s;
}
.primer-reg:hover { background: var(--surface-2); }
.primer-reg .rname {
  font-family: var(--mono);
  font-weight: 700;
  color: var(--accent);
  font-size: 0.85rem;
}
.primer-reg .rdesc {
  color: var(--muted);
  font-size: 0.78rem;
  line-height: 1.4;
}
.primer-reg .rdesc strong { color: var(--text); font-weight: 600; }
.primer-reg .rdesc code { font-size: 0.85em; }

.primer-regs-vals {
  background: #0b0d12;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 6px 10px;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 4px 14px;
}
.primer-rval {
  display: flex;
  justify-content: space-between;
  font-family: var(--mono);
  font-size: 0.82rem;
  padding: 2px 4px;
  border-radius: 3px;
}
.primer-rval .rname { color: var(--muted); }
.primer-rval .rval  { color: var(--text); transition: color 0.2s; }
.primer-rval.changed .rval { color: var(--c-warn); }

/* Hover highlighting from register name → into viz */
.primer-viz.hl-rip .rip-line {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}
.primer-viz.hl-rbp .rbp-line {
  outline: 2px solid var(--c-rbp);
  outline-offset: 1px;
}
/* RSP, RAX, and RDI have no spatial target — highlight their live value row instead */
.primer-regs-vals.hl-rsp .primer-rval[data-reg="rsp"],
.primer-regs-vals.hl-rax .primer-rval[data-reg="rax"],
.primer-regs-vals.hl-rdi .primer-rval[data-reg="rdi"] {
  background: rgba(110, 168, 255, 0.18);
  outline: 1px solid var(--accent);
}

/* ---------- Section 2: stack frames ---------- */
.stack-frame-viz {
  display: flex;
  flex-direction: column-reverse; /* high addresses on top, RSP grows down visually */
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #0b0d12;
  padding: 8px;
  min-height: 380px;
  font-family: var(--mono);
  font-size: 0.85rem;
  gap: 6px;
  position: relative;
}
.frame {
  background: rgba(248, 113, 113, 0.08);
  border: 1px solid var(--c-stack);
  border-radius: 6px;
  padding: 6px 8px;
  position: relative;
  animation: framePush 0.3s ease-out;
}
.frame.current {
  background: rgba(248, 113, 113, 0.18);
  box-shadow: 0 0 0 2px var(--c-stack);
}
.frame-label {
  font-weight: 700;
  color: var(--c-stack);
  margin-bottom: 4px;
  font-size: 0.78rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}
.slot {
  display: flex;
  justify-content: space-between;
  padding: 3px 6px;
  border-radius: 3px;
  margin-bottom: 2px;
}
.slot .lbl { color: var(--muted); }
.slot .val { color: var(--text); }
.slot.retaddr { background: rgba(236, 72, 153, 0.18); }
.slot.retaddr .val { color: var(--c-retaddr); font-weight: 600; }
.slot.rbp { background: rgba(192, 132, 252, 0.12); }
.slot.rbp .val { color: var(--c-rbp); }
.slot.local .val { color: var(--c-bss); }
.slot.arg .val { color: var(--c-data); }
.slot.canary { background: rgba(234, 179, 8, 0.18); }
.slot.canary .val { color: var(--c-canary); font-weight: 600; }
.slot.clobbered { background: rgba(239, 68, 68, 0.25); animation: clobberFlash 0.4s ease-out; }
.slot.clobbered .val { color: var(--c-clobber); font-weight: 700; }

@keyframes framePush {
  from { opacity: 0; transform: translateY(-8px); }
  to   { opacity: 1; transform: translateY(0); }
}
@keyframes clobberFlash {
  from { background: rgba(239, 68, 68, 0.6); }
  to   { background: rgba(239, 68, 68, 0.25); }
}

/* ---------- Section 3: heap ---------- */
.heap-viz {
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #0b0d12;
  padding: 12px;
  min-height: 200px;
  display: flex;
  align-items: stretch;
  gap: 4px;
  font-family: var(--mono);
  font-size: 0.78rem;
  flex-wrap: wrap;
  overflow-x: auto;
}
.chunk {
  display: flex;
  flex-direction: column;
  border-radius: 6px;
  padding: 6px 10px;
  min-width: 90px;
  animation: chunkAppear 0.3s ease-out;
  position: relative;
}
.chunk-header {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  opacity: 0.85;
}
.chunk-meta {
  font-size: 0.7rem;
  opacity: 0.7;
  margin-top: 2px;
}
.chunk-body {
  margin-top: 6px;
  font-weight: 600;
}
.chunk.allocated {
  background: rgba(74, 222, 128, 0.18);
  border: 1px solid var(--c-heap);
  color: var(--c-heap);
}
.chunk.free {
  background: rgba(107, 114, 128, 0.18);
  border: 1px dashed var(--muted);
  color: var(--muted);
}
.chunk.uaf {
  background: rgba(239, 68, 68, 0.25);
  border: 1px solid var(--c-clobber);
  color: var(--c-clobber);
  animation: clobberFlash 0.4s ease-out;
}
.chunk.double-free {
  background: rgba(245, 158, 11, 0.25);
  border: 1px solid var(--c-warn);
  color: var(--c-warn);
}
@keyframes chunkAppear {
  from { opacity: 0; transform: scale(0.92); }
  to   { opacity: 1; transform: scale(1); }
}

/* ---------- Section 4: overflow ---------- */
.mit-intro {
  margin: 0 0 10px;
  color: var(--muted);
  font-size: 0.88rem;
}
.mitigations {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin-bottom: 14px;
}
@media (max-width: 1100px) {
  .mitigations { grid-template-columns: 1fr; }
}
.mit-row {
  position: relative;
  display: flex;
  align-items: center;
  gap: 8px;
  background: #0b0d12;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 10px 12px;
  transition: border-color 0.15s;
}
.mit-row:has(input:checked) {
  border-color: var(--c-ok);
  box-shadow: 0 0 0 1px var(--c-ok) inset;
}
.mit-row label {
  flex: 1;
  display: flex;
  align-items: center;
  cursor: pointer;
  font-family: var(--mono);
  font-size: 0.92rem;
  color: var(--text);
}
.mit-row label input { margin-right: 6px; vertical-align: middle; }
.mit-row label strong { color: var(--accent); font-weight: 600; margin-right: 4px; }

.help-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 20px;
  height: 20px;
  flex-shrink: 0;
  border-radius: 50%;
  background: var(--surface-2);
  border: 1px solid var(--border);
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.78rem;
  font-weight: 700;
  cursor: help;
  user-select: none;
  transition: background 0.15s, color 0.15s, border-color 0.15s;
}
.help-icon:hover,
.help-icon:focus {
  background: var(--accent);
  color: #0b0d12;
  border-color: var(--accent);
  outline: none;
}

.help-popover {
  display: none;
  position: absolute;
  top: calc(100% - 1px);
  left: 0;
  right: 0;
  padding: 12px 14px;
  background: #0b0d12;
  border: 1px solid var(--accent);
  border-radius: 6px;
  color: var(--text);
  font-family: -apple-system, system-ui, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  font-size: 0.85rem;
  line-height: 1.5;
  z-index: 100;
  box-shadow: 0 8px 24px rgba(0,0,0,0.6);
}
.help-popover code { font-size: 0.85em; }
.help-icon:hover ~ .help-popover,
.help-icon:focus ~ .help-popover,
.help-popover:hover {
  display: block;
}

.overflow-viz {
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #0b0d12;
  padding: 12px;
  font-family: var(--mono);
  font-size: 0.8rem;
  display: grid;
  grid-template-columns: 100px 1fr 1fr;
  gap: 0;
  min-height: 360px;
}
.overflow-viz .col-head {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--muted);
  padding: 4px 8px;
  border-bottom: 1px solid var(--border);
}
.overflow-row {
  display: contents;
}
.overflow-row > div {
  padding: 4px 8px;
  border-bottom: 1px solid rgba(255,255,255,0.04);
}
.overflow-row .addr { color: var(--muted); }
.overflow-row .label { color: var(--text); }
.overflow-row .bytes {
  letter-spacing: 0.06em;
  color: var(--muted);
}
.overflow-row.region-buf .label { color: var(--c-bss); }
.overflow-row.region-secret .label { color: var(--c-data); }
.overflow-row.region-canary .label { color: var(--c-canary); }
.overflow-row.region-rbp .label { color: var(--c-rbp); }
.overflow-row.region-ret .label { color: var(--c-retaddr); }
.overflow-row.written .bytes { color: #fff; font-weight: 600; }
.overflow-row.clobbered .bytes,
.overflow-row.clobbered .label {
  color: var(--c-clobber);
  font-weight: 700;
}
.overflow-row.clobbered { background: rgba(239, 68, 68, 0.12); }

/* ---------- Asm panel + registers ---------- */
.asm {
  background: #0b0d12;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 10px;
  font-size: 0.82rem;
  margin: 0;
  line-height: 1.5;
  max-height: 240px;
  overflow-y: auto;
}
.asm .line { padding: 1px 6px; border-radius: 3px; }
.asm .line.current {
  background: rgba(110, 168, 255, 0.18);
  color: var(--accent);
  font-weight: 600;
  border-left: 2px solid var(--accent);
  padding-left: 4px;
}
.asm .mnem { color: var(--accent-2); }
.asm .reg { color: var(--c-data); }
.asm .imm { color: var(--c-heap); }
.asm .addr { color: var(--muted); }

.regs {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 4px 10px;
  font-family: var(--mono);
  font-size: 0.85rem;
  background: #0b0d12;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 10px;
}
.regs .rname { color: var(--muted); }
.regs .rval { color: var(--text); }
.regs .rval.changed { color: var(--c-warn); animation: clobberFlash 0.4s ease-out; }

/* ---------- Footer ---------- */
footer {
  text-align: center;
  padding: 30px 20px 60px;
  color: var(--muted);
  font-size: 0.85rem;
  border-top: 1px solid var(--border);
  margin-top: 20px;
}