:root {
  --bg: #0d1117;
  --panel: #151b24;
  --panel-2: #1b2330;
  --border: #283244;
  --text: #e6edf3;
  --muted: #8b98a9;
  --accent: #58a6ff;
  --accent-2: #1f6feb;
  --esp: #f0883e;
  --ebp: #3fb950;
  --eip: #d2a8ff;
  --ret: #d29922;
  --bad: #f85149;
  --frame: rgba(88, 166, 255, 0.09);
  --changed: rgba(240, 136, 62, 0.28);
  --free: 0.42;
  --mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Consolas, monospace;
  --sans: 'Inter', system-ui, -apple-system, 'Segoe UI', sans-serif;
  color-scheme: dark;
}
:root[data-theme="light"] {
  --bg: #f4f6fa;
  --panel: #ffffff;
  --panel-2: #f0f3f8;
  --border: #d5dce6;
  --text: #1c2430;
  --muted: #5b6878;
  --accent: #0969da;
  --accent-2: #0969da;
  --esp: #bc4c00;
  --ebp: #1a7f37;
  --eip: #8250df;
  --ret: #9a6700;
  --bad: #cf222e;
  --frame: rgba(9, 105, 218, 0.07);
  --changed: rgba(188, 76, 0, 0.18);
  --free: 0.5;
  color-scheme: light;
}

* { box-sizing: border-box; font-variant-ligatures: none !important; font-feature-settings: "calt" 0, "liga" 0 !important; }
[hidden] { display: none !important; }
html, body { margin: 0; }
body {
  background: var(--bg);
  color: var(--text);
  font: 14px/1.45 var(--sans);
  padding: 16px;
}
button, input, select, textarea { font: inherit; color: inherit; }
code, kbd { font-family: var(--mono); font-size: 0.92em; }
kbd { border: 1px solid var(--border); border-bottom-width: 2px; border-radius: 4px; padding: 0 4px; }
.muted { color: var(--muted); font-weight: 400; }

/* header */
.top { display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap; margin-bottom: 14px; }
.brand { display: flex; align-items: center; gap: 12px; }
.logo { font-size: 28px; color: var(--accent); }
h1 { font-size: 20px; margin: 0; letter-spacing: -0.01em; }
.sub { margin: 0; color: var(--muted); font-size: 13px; }
.top-actions { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; }
.sel { display: flex; align-items: center; gap: 6px; color: var(--muted); font-size: 13px; }

select, input {
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 6px 8px;
  min-width: 0;
}
button, .btnlink {
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 6px 12px;
  cursor: pointer;
  text-decoration: none;
  white-space: nowrap;
}
button:hover:not(:disabled), .btnlink:hover { border-color: var(--accent); }
button:disabled { opacity: 0.45; cursor: default; }
button.primary { background: var(--accent-2); border-color: var(--accent-2); color: #fff; font-weight: 600; }
button.ghost, .ghost { background: transparent; }
button.small { padding: 2px 8px; font-size: 12px; }
button.active-run { border-color: var(--esp); color: var(--esp); }

/* layout */
.grid {
  display: grid;
  grid-template-columns: minmax(300px, 1fr) minmax(420px, 1.35fr) minmax(300px, 0.95fr);
  gap: 14px;
  align-items: start;
}
.side { display: flex; flex-direction: column; gap: 14px; min-width: 0; }
.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px;
  min-width: 0;
}
.panel-head { display: flex; align-items: center; justify-content: space-between; gap: 8px; margin-bottom: 10px; }
h2 { font-size: 14px; margin: 0; text-transform: uppercase; letter-spacing: 0.06em; }
h2 .muted { text-transform: none; letter-spacing: 0; font-size: 12px; }

/* code panel */
.tabs { display: flex; gap: 4px; }
.tab { padding: 3px 10px; font-size: 12px; }
.tab.active { border-color: var(--accent); color: var(--accent); }
.editor-wrap, .listing {
  height: 430px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--panel-2);
  font: 13px/20px var(--mono);
}
.editor-wrap { display: flex; overflow: hidden; }
.gutter {
  margin: 0;
  padding: 8px 8px 8px 6px;
  text-align: right;
  color: var(--muted);
  opacity: 0.6;
  user-select: none;
  overflow: hidden;
  min-width: 36px;
  font: inherit;
}
.gutter .err { color: var(--bad); opacity: 1; font-weight: 700; }
textarea {
  flex: 1;
  border: 0;
  outline: none;
  resize: none;
  background: transparent;
  padding: 8px;
  font: inherit;
  tab-size: 4;
  white-space: pre;
  overflow: auto;
}
.listing { overflow: auto; padding: 6px 0; }
.lst-label { padding: 0 10px; color: var(--ebp); }
.lst-row { display: grid; grid-template-columns: 16px 92px 1fr; padding: 0 10px 0 4px; cursor: pointer; border-left: 3px solid transparent; }
.lst-row:hover { background: var(--frame); }
.lst-row .bp { color: var(--bad); text-align: center; }
.lst-row .addr { color: var(--muted); }
.lst-row.cur { background: rgba(210, 168, 255, 0.16); border-left-color: var(--eip); }
.lst-row.cur .addr { color: var(--eip); font-weight: 700; }
.lst-row.prev { background: rgba(139, 152, 169, 0.1); }

.asm-errors { margin-top: 8px; border: 1px solid var(--bad); border-radius: 8px; padding: 8px 10px; color: var(--bad); font: 12px/1.5 var(--mono); max-height: 120px; overflow: auto; }
.asm-errors div { cursor: pointer; }
.controls { display: flex; flex-direction: column; gap: 8px; margin-top: 10px; }
.btn-row { display: grid; grid-template-columns: repeat(4, 1fr); gap: 6px; }
.btn-row button { padding: 6px 4px; }
.speed { display: flex; align-items: center; gap: 8px; color: var(--muted); font-size: 12px; }
.speed input { flex: 1; padding: 0; }
.status { margin-top: 10px; padding: 8px 10px; border-radius: 8px; background: var(--panel-2); font-size: 13px; border-left: 3px solid var(--muted); }
.status.ok { border-left-color: var(--ebp); }
.status.bad { border-left-color: var(--bad); color: var(--bad); }
.status.warn { border-left-color: var(--ret); }

/* stack */
.legend { display: flex; flex-wrap: wrap; gap: 4px 12px; font-size: 12px; color: var(--muted); margin-bottom: 8px; }
.sw { display: inline-block; width: 10px; height: 10px; border-radius: 2px; margin-right: 5px; vertical-align: -1px; border: 1px solid var(--border); }
.sw-frame { background: var(--frame); border-color: var(--accent); }
.sw-ret { background: var(--ret); }
.sw-ebp { background: var(--ebp); }
.sw-free { background: transparent; border-style: dashed; }
.sw-bad { background: var(--bad); }
.stack-cols, .srow {
  display: grid;
  grid-template-columns: 78px 96px 64px 96px 44px minmax(0, 1fr);
  gap: 6px;
  align-items: center;
}
.stack-cols { font-size: 11px; color: var(--muted); text-transform: uppercase; letter-spacing: 0.05em; padding: 0 8px 4px; border-bottom: 1px solid var(--border); }
.stack-view { height: 640px; overflow: auto; font: 12.5px/1 var(--mono); position: relative; }
.srow { padding: 0 8px; height: 30px; border-bottom: 1px solid var(--border); border-left: 3px solid transparent; position: relative; }
.srow.frame { background: var(--frame); }
.srow.free > :not(.ptrs) { opacity: var(--free); }
.srow.free { border-bottom-style: dashed; }
.srow.changed .val { background: var(--changed); border-radius: 4px; }
.srow.k-ret { border-left-color: var(--ret); }
.srow.k-ebp { border-left-color: var(--ebp); }
.srow.corrupt { border-left-color: var(--bad); }
.srow.corrupt .val, .srow.corrupt .note { color: var(--bad); font-weight: 700; }
.srow .addr { color: var(--muted); }
.srow .off { color: var(--muted); font-size: 11.5px; }
.srow .val { padding: 3px 4px; margin-left: -4px; transition: background 0.4s; }
.srow .ascii { color: var(--muted); white-space: pre; }
.srow .note { font-family: var(--sans); font-size: 12px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.srow.k-ret .note { color: var(--ret); }
.srow.k-ebp .note { color: var(--ebp); }
.srow.frame-top { border-top: 2px solid var(--accent); }
.ptrs { display: flex; gap: 3px; }
.ptr { font-size: 10.5px; font-weight: 700; padding: 3px 5px; border-radius: 4px; color: #fff; }
.ptr.esp { background: var(--esp); }
.ptr.ebp { background: var(--ebp); }
:root[data-theme="light"] .ptr { color: #fff; }
.stack-gap { text-align: center; color: var(--muted); font: 11px var(--sans); padding: 6px; border-bottom: 1px dashed var(--border); }

/* registers */
.regs { display: grid; grid-template-columns: 1fr 1fr; gap: 6px; }
.reg { background: var(--panel-2); border: 1px solid var(--border); border-radius: 7px; padding: 6px 8px; font-family: var(--mono); transition: border-color 0.3s, background 0.3s; min-width: 0; }
.reg .n { font-size: 11px; font-weight: 700; color: var(--muted); text-transform: uppercase; display: flex; justify-content: space-between; gap: 4px; }
.reg .n em { font-style: normal; font-weight: 400; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.reg .v { font-size: 14px; }
.reg.changed { background: var(--changed); border-color: var(--esp); }
.reg.r-esp .n b { color: var(--esp); }
.reg.r-ebp .n b { color: var(--ebp); }
.reg.r-eip { grid-column: 1 / -1; }
.reg.r-eip .n b { color: var(--eip); }
.flags { display: flex; gap: 6px; margin-top: 8px; flex-wrap: wrap; }
.flag { font: 12px var(--mono); padding: 3px 8px; border-radius: 12px; border: 1px solid var(--border); color: var(--muted); }
.flag.on { color: var(--text); border-color: var(--accent); background: var(--frame); }

/* playground */
.hint { margin: -4px 0 8px; color: var(--muted); font-size: 12px; }
.pg-row { display: flex; gap: 6px; margin-bottom: 6px; }
.pg-row input, .pg-row select { flex: 1; font-family: var(--mono); font-size: 13px; }
.pg-row button { width: 64px; font-family: var(--mono); }

/* explanation */
.explain-now { background: var(--panel-2); border-radius: 8px; padding: 10px; min-height: 60px; font-size: 13.5px; border-left: 3px solid var(--eip); }
.explain-now .ins { display: block; font-family: var(--mono); color: var(--eip); font-weight: 700; margin-bottom: 4px; }
.explain-now.fault { border-left-color: var(--bad); }
.log { margin: 8px 0 0; padding: 0 0 0 30px; max-height: 260px; overflow: auto; font-size: 12px; color: var(--muted); }
.log li { margin-bottom: 4px; }
.log code { color: var(--text); }
.log li.fault code, .log li.fault { color: var(--bad); }

/* reference */
.ref { margin-top: 14px; }
.ref summary { cursor: pointer; font-weight: 600; }
.ref-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 18px; margin-top: 10px; }
.ref h3 { font-size: 13px; margin: 8px 0; }
.ref table { border-collapse: collapse; width: 100%; font-size: 12.5px; }
.ref td { border-bottom: 1px solid var(--border); padding: 4px 6px; vertical-align: top; }
.ref ul { padding-left: 18px; margin: 0; font-size: 12.5px; }
.ref li { margin-bottom: 4px; }
.foot { text-align: center; color: var(--muted); font-size: 12px; margin-top: 14px; }

@media (max-width: 1200px) {
  .grid { grid-template-columns: minmax(0, 1fr) minmax(0, 1.3fr); }
  .side { grid-column: 1 / -1; display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .stack-view { height: 560px; }
}
@media (max-width: 820px) {
  body { padding: 16px; }
  .grid, .side, .ref-grid { grid-template-columns: minmax(0, 1fr); }
  .side { display: flex; }
  .editor-wrap, .listing { height: 320px; }
  .stack-view { height: 460px; }
  .stack-cols, .srow { grid-template-columns: 64px 88px 56px 88px minmax(0, 1fr); }
  .stack-cols span:nth-child(5), .srow .ascii { display: none; }
  .stack-cols span:nth-child(3), .srow .off { font-size: 10.5px; }
}
@media (max-width: 480px) {
  .stack-cols, .srow { grid-template-columns: 58px 84px 84px minmax(0, 1fr); font-size: 11.5px; }
  .stack-cols span:nth-child(3), .srow .off { display: none; }
  .btn-row { grid-template-columns: repeat(2, 1fr); }
}

/* ---------------------------------------------------------- beginner-friendly additions */
:root { --arg: #a371f7; --local: #58a6ff; }
:root[data-theme="light"] { --arg: #8250df; --local: #0969da; }
.c-esp { color: var(--esp); } .c-ebp { color: var(--ebp); } .c-eip { color: var(--eip); }
.c-ret { color: var(--ret); } .c-arg { color: var(--arg); } .c-local { color: var(--local); }

/* segmented toggles */
.seg { display: inline-flex; border: 1px solid var(--border); border-radius: 7px; overflow: hidden; }
.seg button { border: 0; border-radius: 0; background: transparent; padding: 6px 10px; font-size: 13px; color: var(--muted); }
.seg button + button { border-left: 1px solid var(--border); }
.seg button.on { background: var(--accent-2); color: #fff; font-weight: 600; }

/* intro */
.intro { margin-bottom: 14px; }
.intro-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 10px; }
.card { background: var(--panel-2); border: 1px solid var(--border); border-radius: 8px; padding: 10px 12px; }
.card h3 { margin: 0 0 6px; font-size: 14px; }
.card p { margin: 0; font-size: 13px; color: var(--text); }
.frame-card { grid-row: span 2; }
.frame-card pre { margin: 0; font: 12.5px/1.65 var(--mono); white-space: pre; overflow-x: auto; }

/* tooltip */
.tip {
  position: fixed; z-index: 50; max-width: 300px; pointer-events: none;
  background: var(--text); color: var(--bg); font-size: 12.5px; line-height: 1.45;
  padding: 7px 10px; border-radius: 7px; box-shadow: 0 6px 20px rgba(0, 0, 0, 0.3);
}
[data-tip] { cursor: help; }
button[data-tip], .seg[data-tip] { cursor: pointer; }

/* stack: slot kinds */
.sw-arg { background: var(--arg); }
.srow.k-arg { border-left-color: var(--arg); }
.srow.k-arg .note { color: var(--arg); }
.srow.k-local .note { color: var(--local); }
.srow.k-data .note, .srow.k-push .note { color: var(--muted); }
.srow.corrupt .note { color: var(--bad); }

/* floating ESP / EBP arrows */
.stack-view { position: relative; }
.stack-view .ptr { position: absolute; left: 6px; top: 0; z-index: 2; transition: top 0.4s cubic-bezier(0.3, 0.7, 0.3, 1); box-shadow: 0 2px 6px rgba(0, 0, 0, 0.25); }
.stack-view .ptr.ebp.shift { left: 50px; }
body.beginner .stack-view .ptr.ebp.shift { left: 56px; }
.stack-view .ptr.no-anim { transition: none; }

/* animations */
@keyframes slideIn { from { transform: translateX(-30px); opacity: 0; } to { transform: none; opacity: 1; } }
@keyframes popFlash { 0% { background: var(--changed); } 100% { background: transparent; } }
@keyframes valFlash { 0% { background: var(--esp); color: #fff; } 100% { background: var(--changed); } }
@keyframes regFlash { 0% { transform: scale(1.04); } 100% { transform: none; } }
@keyframes fadeIn { from { opacity: 0; transform: translateY(4px); } to { opacity: 1; transform: none; } }
.srow.anim-push { animation: slideIn 0.4s ease-out; }
.srow.anim-pop { animation: popFlash 0.9s ease-out; }
.srow.anim-pop .note { color: var(--esp) !important; }
.srow.changed .val { animation: valFlash 0.7s ease-out; }
.reg.changed { animation: regFlash 0.35s ease-out; }
.explain-now.fresh { animation: fadeIn 0.3s ease-out; }
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; }
}

/* beginner mode: fewer columns, plainer view */
body.beginner .expert-only,
body.beginner .srow .off, body.beginner .srow .ascii,
body.beginner .stack-cols .col-off, body.beginner .stack-cols .col-ascii { display: none; }
body.beginner .stack-cols, body.beginner .srow { grid-template-columns: 104px 100px 110px minmax(0, 1fr); }
body.beginner .srow { height: auto; min-height: 34px; padding-top: 4px; padding-bottom: 4px; }
body.beginner .srow .note { white-space: normal; line-height: 1.3; }
body.beginner .srow .val { font-size: 13.5px; font-weight: 500; }
body.beginner .srow .note { font-size: 12.5px; }
body.beginner .explain-now { font-size: 14.5px; line-height: 1.55; }
body:not(.beginner) .stack-cols, body:not(.beginner) .srow { grid-template-columns: 96px 96px 64px 96px 44px minmax(0, 1fr); }

@media (max-width: 1200px) {
  .intro-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 820px) {
  .intro-grid { grid-template-columns: minmax(0, 1fr); }
  .frame-card { grid-row: auto; }
  body:not(.beginner) .stack-cols, body:not(.beginner) .srow { grid-template-columns: 92px 88px 56px 88px minmax(0, 1fr); }
  body.beginner .stack-cols, body.beginner .srow { grid-template-columns: 100px 88px 96px minmax(0, 1fr); }
}
@media (max-width: 480px) {
  body:not(.beginner) .stack-cols, body:not(.beginner) .srow,
  body.beginner .stack-cols, body.beginner .srow { grid-template-columns: 96px 84px 84px minmax(0, 1fr); font-size: 11.5px; }
  .top-actions { gap: 6px; }
}

/* ---------------------------------------------------------- graph mode */
:root { --g-true: #3fb950; --g-false: #f85149; --g-jmp: #58a6ff; }
:root[data-theme="light"] { --g-true: #1a7f37; --g-false: #cf222e; --g-jmp: #0969da; }
.graph { height: 520px; display: flex; flex-direction: column; border: 1px solid var(--border); border-radius: 8px; background: var(--panel-2); overflow: hidden; }
.gbar { display: flex; align-items: center; gap: 6px; padding: 6px 8px; border-bottom: 1px solid var(--border); }
.gbar select { padding: 3px 6px; font: 12.5px var(--mono); }
.gfollow { font-size: 12px; color: var(--muted); display: flex; align-items: center; gap: 4px; }
.gspacer { flex: 1; }
.gbar .gz { min-width: 30px; }
.glegend { display: flex; flex-wrap: wrap; gap: 4px 12px; padding: 4px 10px; font-size: 11.5px; color: var(--muted); border-bottom: 1px solid var(--border); }
.gl { display: inline-block; width: 16px; height: 0; border-top: 2px solid; vertical-align: 3px; margin-right: 5px; }
.gl-true { border-color: var(--g-true); } .gl-false { border-color: var(--g-false); } .gl-jmp { border-color: var(--g-jmp); }
.gscroll { flex: 1; overflow: auto; position: relative; }
.gsizer { position: relative; margin: 0 auto; }
.gcanvas { position: absolute; left: 0; top: 0; transform-origin: 0 0; }
.gempty { padding: 20px; color: var(--muted); }
.gsvg { position: absolute; left: 0; top: 0; overflow: visible; pointer-events: none; }
.gblock {
  position: absolute; background: var(--panel); border: 1.5px solid var(--border); border-radius: 7px;
  font: 12px/18px var(--mono); white-space: nowrap; min-width: 120px; box-shadow: 0 2px 8px rgba(0, 0, 0, 0.18);
  transition: border-color 0.25s, box-shadow 0.25s;
}
.gblock.gcur { border-color: var(--eip); box-shadow: 0 0 0 3px rgba(210, 168, 255, 0.22); }
.ghead { padding: 3px 10px; color: var(--ebp); font-weight: 700; border-bottom: 1px solid var(--border); background: var(--panel-2); border-radius: 6px 6px 0 0; }
.gline { display: flex; gap: 8px; padding: 0 10px 0 4px; cursor: pointer; border-left: 3px solid transparent; }
.gline:hover { background: var(--frame); }
.gline .gbp { width: 8px; color: var(--bad); font-size: 10px; }
.gline .ga { color: var(--muted); }
.gline.cur { background: rgba(210, 168, 255, 0.18); border-left-color: var(--eip); }
.gline.cur .ga { color: var(--eip); font-weight: 700; }
.gline.prev { background: rgba(139, 152, 169, 0.12); }
.gcall { color: var(--accent); cursor: pointer; font-weight: 700; padding: 0 2px; border-radius: 3px; }
.gcall:hover { background: var(--frame); }
.gedge { fill: none; stroke-width: 1.8; opacity: 0.85; transition: stroke-width 0.2s, opacity 0.2s; }
.ge-true { stroke: var(--g-true); } .ge-false { stroke: var(--g-false); } .ge-jmp { stroke: var(--g-jmp); }
.gm-true { fill: var(--g-true); } .gm-false { fill: var(--g-false); } .gm-jmp { fill: var(--g-jmp); }
.gedge.hot { stroke-width: 3.5; opacity: 1; stroke-dasharray: 8 5; animation: gflow 0.6s linear infinite; }
@keyframes gflow { to { stroke-dashoffset: -13; } }
.glabel { font: 600 11px var(--mono); paint-order: stroke; stroke: var(--panel-2); stroke-width: 4px; stroke-linejoin: round; }
.glabel.gl-true { fill: var(--g-true); } .glabel.gl-false { fill: var(--g-false); }
.glabel.hot { font-size: 12px; text-decoration: underline; }
@media (max-width: 820px) { .graph { height: 440px; } }