:root {
  --bg:      #030810;
  --panel:   #050d1a;
  --surface: #071223;
  --border:  #0d2040;
  --border2: #1a3a60;
  --text:    #8ab4d4;
  --bright:  #c8e0f0;
  --muted:   #6090b0;
  --scan:    rgba(0,180,255,0.03);

  --cyan:    #00d4ff;
  --green:   #00ff88;
  --amber:   #ffb400;
  --red:     #ff4060;
  --purple:  #a060ff;
  --teal:    #00e0c0;
  --orange:  #ff7020;
}

*{ margin:0; padding:0; box-sizing:border-box; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Rajdhani', sans-serif;
  min-height: 100vh;
  overflow-x: hidden;
}

/* Scanline overlay */
body::before {
  content:'';
  position:fixed; inset:0;
  background: repeating-linear-gradient(
    0deg,
    transparent,
    transparent 2px,
    var(--scan) 2px,
    var(--scan) 4px
  );
  pointer-events:none; z-index:0;
}

/* Subtle CRT glow */
body::after {
  content:'';
  position:fixed; inset:0;
  background: radial-gradient(ellipse at 50% 50%, rgba(0,100,200,0.06) 0%, transparent 70%);
  pointer-events:none; z-index:0;
}

/* HEADER */
header {
  position:relative; z-index:1;
  padding: 36px 56px 32px;
  border-bottom: 1px solid var(--border2);
  background: linear-gradient(180deg, rgba(0,30,60,0.8) 0%, transparent 100%);
}
.hdr-top {
  display: flex; align-items: flex-start;
  justify-content: space-between; gap: 40px;
}
.hdr-left {}
.signal-badge {
  font-family: 'Share Tech Mono', monospace;
  font-size: 9px; letter-spacing: 3px;
  color: var(--cyan); margin-bottom: 14px;
  display: flex; align-items: center; gap: 8px;
}
.sig-dot {
  width: 6px; height: 6px; border-radius: 50%;
  background: var(--cyan);
  animation: pulse 1.2s ease-in-out infinite;
}
@keyframes pulse {
  0%,100% { opacity:1; box-shadow:0 0 4px var(--cyan); }
  50%      { opacity:0.4; box-shadow:none; }
}
header h1 {
  font-family: 'Orbitron', monospace;
  font-size: clamp(28px, 4vw, 52px);
  font-weight: 900;
  color: var(--bright);
  line-height: 1.1;
  margin-bottom: 8px;
  text-shadow: 0 0 20px rgba(0,212,255,0.3);
}
header h1 span { color: var(--cyan); }
.hdr-sub {
  font-family: 'Share Tech Mono', monospace;
  font-size: 11px; color: var(--muted);
  letter-spacing: 1px; line-height: 1.8;
}

/* Live stats panel */
.stats-panel {
  display: grid; grid-template-columns: repeat(4,1fr);
  gap: 10px; min-width: 400px;
}
.stat-box {
  border: 1px solid var(--border2);
  background: var(--panel);
  padding: 12px 14px;
  text-align: center;
}
.stat-val {
  font-family: 'Orbitron', monospace;
  font-size: 20px; font-weight: 700;
  line-height: 1;
  margin-bottom: 4px;
}
.stat-lbl {
  font-family: 'Share Tech Mono', monospace;
  font-size: 8px; letter-spacing: 1px;
  color: var(--muted);
}

/* Color bar */
.cbar {
  display: flex; height: 3px; margin-top: 20px;
  gap: 2px;
}
.cbar-seg { flex:1; }

/* NAV */
.nav {
  position: sticky; top: 0; z-index: 100;
  background: var(--panel);
  display: flex; overflow-x: auto;
  border-bottom: 1px solid var(--border2);
}
.nav-tab {
  padding: 13px 18px;
  font-family: 'Share Tech Mono', monospace;
  font-size: 10px; letter-spacing: 1.5px;
  text-transform: uppercase;
  color: var(--muted); cursor: pointer;
  border-bottom: 2px solid transparent;
  transition: all 0.15s; white-space: nowrap;
}
.nav-tab:hover { color: var(--text); }
.nav-tab.active { color: var(--cyan); border-bottom-color: var(--cyan); }

/* CONTENT */
.content { padding: 44px 56px; position: relative; z-index: 1; max-width: 1300px; }
.view { display: none; }
.view.active { display: block; }

/* Section heading */
.sec-hd {
  font-family: 'Share Tech Mono', monospace;
  font-size: 9px; letter-spacing: 3px;
  color: var(--muted); text-transform: uppercase;
  margin-bottom: 14px;
  display: flex; align-items: center; gap: 10px;
}
.sec-hd::after { content:''; flex:1; height:1px; background:var(--border2); }

/* Concept grid — memory model cards */
.concept-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px; margin-bottom: 28px;
}
.concept-card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 18px 20px;
  position: relative; overflow: hidden;
  transition: border-color 0.2s;
}
.concept-card:hover { border-color: var(--border2); }
.concept-card::before {
  content: '';
  position: absolute; top: 0; left: 0; right: 0;
  height: 2px;
}
.cc-num {
  font-family: 'Orbitron', monospace;
  font-size: 9px; letter-spacing: 2px;
  color: var(--muted); margin-bottom: 8px;
}
.cc-name {
  font-family: 'Rajdhani', sans-serif;
  font-size: 16px; font-weight: 700;
  color: var(--bright); margin-bottom: 6px;
}
.cc-desc { font-size: 12px; color: var(--muted); line-height: 1.6; }

/* CODE BLOCKS */
.code-block {
  background: #020609;
  border: 1px solid var(--border2);
  border-radius: 4px;
  overflow: hidden;
  margin: 14px 0;
}
.code-hdr {
  display: flex; justify-content: space-between; align-items: center;
  padding: 7px 14px;
  background: var(--panel);
  border-bottom: 1px solid var(--border);
  font-family: 'Share Tech Mono', monospace;
  font-size: 9px; color: var(--muted); letter-spacing: 1px;
}
.clang { color: var(--cyan); }
pre.code {
  padding: 16px 18px;
  font-family: 'Share Tech Mono', monospace;
  font-size: 11.5px; line-height: 1.85;
  color: #4a7a9a; overflow-x: auto; white-space: pre;
}
.kw  { color: #00b4d4; }
.cls { color: #88c0d0; }
.fn  { color: var(--green); }
.cm  { color: #1a3a50; }
.str { color: var(--amber); }
.ann { color: var(--purple); }
.hl  { color: var(--red); }
.ok  { color: var(--green); }
.num { color: var(--teal); }

/* Primitive comparison table */
.prim-table {
  width: 100%; border-collapse: collapse;
  font-size: 12px; margin: 14px 0;
}
.prim-table th {
  background: var(--surface);
  padding: 9px 13px;
  font-family: 'Share Tech Mono', monospace;
  font-size: 9px; letter-spacing: 1px;
  color: var(--cyan); font-weight: 400;
  text-align: left;
  border-bottom: 1px solid var(--border2);
}
.prim-table td {
  padding: 9px 13px;
  border-bottom: 1px solid var(--border);
  color: var(--muted); vertical-align: top;
  line-height: 1.5;
}
.prim-table td:first-child {
  font-family: 'Share Tech Mono', monospace;
  font-size: 11px; color: var(--cyan);
}
.prim-table tr:hover td { background: rgba(0,100,180,0.04); }
.yes { color: var(--green) !important; }
.no  { color: var(--red)   !important; }

/* Pill */
.pill {
  display: inline-block;
  font-family: 'Share Tech Mono', monospace;
  font-size: 9px; letter-spacing: 0.5px;
  padding: 2px 8px; border-radius: 2px;
  border: 1px solid;
}

/* Diagram boxes */
.flow-row {
  display: flex; align-items: center;
  gap: 0; margin: 16px 0; flex-wrap: wrap;
}
.flow-box {
  padding: 10px 16px;
  border: 1px solid;
  font-family: 'Share Tech Mono', monospace;
  font-size: 11px; text-align: center;
  flex-shrink: 0;
}
.flow-arrow {
  padding: 0 6px;
  color: var(--muted); font-size: 14px;
  font-family: 'Share Tech Mono', monospace;
}
.flow-label {
  font-size: 8px; letter-spacing: 0.5px; margin-top: 3px;
  color: var(--muted);
}

/* Deadlock visualiser */
.dl-grid {
  display: grid; grid-template-columns: 1fr 1fr;
  gap: 14px; margin: 14px 0;
}
.dl-card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 4px; overflow: hidden;
}
.dl-hdr {
  padding: 8px 14px;
  font-family: 'Share Tech Mono', monospace;
  font-size: 9px; letter-spacing: 2px;
  border-bottom: 1px solid var(--border);
}
.dl-body { padding: 14px; }

/* Alert / tip box */
.alert {
  margin: 14px 0; padding: 12px 16px;
  border-left: 3px solid;
  background: rgba(0,0,0,0.3);
  font-family: 'Share Tech Mono', monospace;
  font-size: 11px; line-height: 1.7;
}
.alert.warn  { border-color: var(--amber); color: var(--amber); }
.alert.info  { border-color: var(--cyan);  color: var(--cyan);  }
.alert.good  { border-color: var(--green); color: var(--green); }
.alert.error { border-color: var(--red);   color: var(--red);   }
.alert em    { color: var(--bright); font-style: normal; font-family:'Rajdhani',sans-serif; font-weight:600; }

/* Projects */
.proj-grid {
  display: grid; grid-template-columns: 1fr 1fr;
  gap: 14px; margin: 16px 0;
}
.proj-card {
  background: var(--panel);
  border: 1px solid var(--border2);
  border-radius: 4px; overflow: hidden;
}
.proj-hdr {
  padding: 14px 18px;
  border-bottom: 1px solid var(--border);
  display: flex; align-items: center; gap: 12px;
}
.proj-icon { font-size: 22px; }
.proj-name {
  font-family: 'Orbitron', monospace;
  font-size: 13px; color: var(--bright);
}
.proj-type {
  font-family: 'Share Tech Mono', monospace;
  font-size: 9px; color: var(--muted);
  letter-spacing: 1px; margin-top: 2px;
}
.proj-body { padding: 14px 18px; }
.tech-stack {
  display: flex; flex-wrap: wrap; gap: 6px;
  margin-top: 10px;
}
.tech-tag {
  font-family: 'Share Tech Mono', monospace;
  font-size: 9px; padding: 3px 8px;
  border: 1px solid var(--border2);
  color: var(--muted); border-radius: 2px;
}

/* Tasks */
.task-list { display: flex; flex-direction: column; gap: 10px; }
.task-card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 4px; overflow: hidden;
}
.task-hd {
  display: flex; align-items: center; gap: 14px;
  padding: 16px 18px; cursor: pointer;
  transition: background 0.15s;
}
.task-hd:hover { background: var(--surface); }
.t-num {
  font-family: 'Orbitron', monospace;
  font-size: 22px; font-weight: 700;
  color: var(--border2); flex-shrink: 0; line-height: 1;
}
.t-label {
  font-size: 15px; font-weight: 600;
  color: var(--bright); flex: 1;
}
.t-meta {
  font-family: 'Share Tech Mono', monospace;
  font-size: 9px; color: var(--muted); white-space: nowrap;
}
.t-arr { color: var(--muted); font-size: 18px; transition: transform 0.2s; }
.t-arr.open { transform: rotate(90deg); }
.task-bd {
  display: none; padding: 0 18px 18px;
  font-size: 13px; color: var(--muted); line-height: 1.7;
}
.task-bd.open { display: block; }
.task-bd pre {
  background: #020609; border: 1px solid var(--border);
  border-radius: 3px; padding: 12px 14px;
  font-family: 'Share Tech Mono', monospace;
  font-size: 10.5px; line-height: 1.75;
  overflow-x: auto; margin: 10px 0;
  color: #4a7a9a; white-space: pre;
}

/* Checklist */
.chk-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; }
.chk {
  display: flex; align-items: flex-start; gap: 12px;
  padding: 11px 14px;
  background: var(--panel); border: 1px solid var(--border);
  border-radius: 3px; cursor: pointer; transition: all 0.15s;
}
.chk:hover { border-color: var(--border2); }
.chk.done { border-color: rgba(0,255,136,0.25); }
.chk-box {
  width: 14px; height: 14px;
  border: 1px solid var(--border2);
  flex-shrink: 0; margin-top: 2px;
  display: flex; align-items: center; justify-content: center;
  font-size: 9px; transition: all 0.15s;
  font-family: 'Share Tech Mono', monospace;
}
.chk.done .chk-box { background: var(--green); border-color: var(--green); color: #000; }
.chk-lbl { font-size: 12px; color: var(--muted); line-height: 1.5; }
.chk.done .chk-lbl { color: var(--green); text-decoration: line-through; text-decoration-color: rgba(0,255,136,0.4); }

.prog-row {
  display: flex; justify-content: space-between;
  font-family: 'Share Tech Mono', monospace;
  font-size: 10px; margin-bottom: 8px;
}
.prog-track {
  height: 2px; background: var(--border);
  margin-bottom: 24px; overflow: hidden;
}
.prog-fill {
  height: 100%; background: var(--cyan);
  transition: width 0.3s;
  width: 0%;
  box-shadow: 0 0 8px var(--cyan);
}

/* Animation — thread race */
.thread-demo {
  background: var(--panel);
  border: 1px solid var(--border2);
  border-radius: 4px; padding: 20px;
  margin: 16px 0; overflow: hidden;
}
.thread-row {
  display: flex; align-items: center; gap: 10px;
  margin: 8px 0;
  font-family: 'Share Tech Mono', monospace;
  font-size: 11px;
}
.thread-lbl { width: 80px; color: var(--muted); flex-shrink: 0; }
.thread-track {
  flex: 1; height: 20px;
  background: var(--surface);
  border: 1px solid var(--border);
  position: relative; overflow: hidden;
}
.thread-bar {
  position: absolute; top: 0; height: 100%;
  display: flex; align-items: center;
  padding: 0 8px;
  font-size: 9px; letter-spacing: 0.5px;
  color: #000; font-weight: 700;
  animation-timing-function: ease-in-out;
  animation-iteration-count: infinite;
  animation-direction: alternate;
}
.t1-bar { background: var(--cyan);   animation-name: t1; animation-duration: 3.2s; }
.t2-bar { background: var(--purple); animation-name: t2; animation-duration: 3.2s; }
.t3-bar { background: var(--green);  animation-name: t3; animation-duration: 3.2s; }
@keyframes t1 { 0%{left:0;width:30%}  50%{left:20%;width:45%} 100%{left:55%;width:40%} }
@keyframes t2 { 0%{left:5%;width:25%} 50%{left:40%;width:35%} 100%{left:30%;width:50%} }
@keyframes t3 { 0%{left:10%;width:40%}50%{left:60%;width:30%} 100%{left:20%;width:45%} }
.thread-val { width: 60px; text-align: right; color: var(--amber); font-family:'Share Tech Mono',monospace; font-size:10px; }

@media(max-width:900px){
  .content { padding:28px 20px; }
  header { padding:28px 20px; }
  .hdr-top { flex-direction:column; }
  .stats-panel { grid-template-columns:repeat(2,1fr); min-width:unset; }
  .concept-grid { grid-template-columns:1fr 1fr; }
  .dl-grid { grid-template-columns:1fr; }
  .proj-grid { grid-template-columns:1fr; }
  .chk-grid { grid-template-columns:1fr; }
}

/* ── BOTTOM NAV ── */
.m5-bottom-nav {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  justify-content: center;
  padding: 2rem 1.5rem;
  border-top: 1px solid var(--border2, #1a3a60);
  margin-top: 2rem;
}
.m5-nav-footer-btn {
  padding: 0.6rem 1.2rem;
  border: 1px solid var(--border2, #1a3a60);
  border-radius: 6px;
  color: var(--text, #8ab4d4);
  text-decoration: none;
  font-size: 0.85rem;
  font-weight: 600;
  transition: border-color 0.2s, color 0.2s;
}
.m5-nav-footer-btn:hover { border-color: var(--cyan, #00d4ff); color: var(--cyan, #00d4ff); }