:root {
  --bg:        #070a0f;
  --bg2:       #0c121b;
  --panel:     #0f1722;
  --panel2:    #132030;
  --line:      #1c2c40;
  --text:      #c9d6e6;
  --dim:       #6a7d94;
  --cyan:      #22d3ee;
  --pink:      #f471b5;
  --amber:     #fbbf24;
  --danger:    #ff5470;
  --ok:        #38ef7d;
  --mono: ui-monospace, "SFMono-Regular", "JetBrains Mono", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }

html, body { margin: 0; padding: 0; }

body {
  background:
    radial-gradient(1200px 700px at 50% -10%, #122033 0%, transparent 60%),
    linear-gradient(180deg, #070a0f 0%, #05070b 100%);
  color: var(--text);
  font-family: var(--mono);
  font-size: 15px;
  line-height: 1.55;
  min-height: 100vh;
  overflow-x: hidden;
}

/* subtle grid + scanlines */
body::before {
  content: "";
  position: fixed; inset: 0;
  background-image:
    linear-gradient(rgba(34,211,238,0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(34,211,238,0.04) 1px, transparent 1px);
  background-size: 42px 42px;
  pointer-events: none;
  z-index: 0;
  mask-image: radial-gradient(circle at 50% 30%, #000 30%, transparent 85%);
}
body::after {
  content: "";
  position: fixed; inset: 0;
  background: repeating-linear-gradient(180deg, rgba(0,0,0,0) 0 3px, rgba(0,0,0,0.18) 3px 4px);
  pointer-events: none;
  z-index: 1;
  opacity: .35;
}

.wrap { position: relative; z-index: 2; max-width: 1180px; margin: 0 auto; padding: 0 22px 90px; }

/* ---------- branding ---------- */
.topbar {
  position: relative; z-index: 3;
  max-width: 1180px; margin: 0 auto; padding: 16px 22px 0;
  display: flex; align-items: center; justify-content: space-between; gap: 16px; flex-wrap: wrap;
}
.brandbar { display: flex; align-items: center; gap: 12px; }
.logo {
  height: 34px; width: auto; display: block;
  background: #f5f8fc; border: 1px solid var(--line); border-radius: 8px;
  padding: 6px 12px; box-shadow: 0 4px 14px rgba(0,0,0,.35);
}
.course-id { text-align: right; line-height: 1.3; }
.course-id .course-name { display: block; font-size: 11px; letter-spacing: .22em; text-transform: uppercase; color: var(--cyan); }
.course-id .course-who { display: block; font-size: 12px; color: var(--dim); }
@media (max-width: 560px) {
  .topbar { justify-content: center; }
  .course-id { text-align: center; }
}

/* ---------- header ---------- */
header.hero { text-align: center; padding: 70px 0 34px; }
.kicker {
  letter-spacing: .42em; text-transform: uppercase; font-size: 11px;
  color: var(--cyan); opacity: .85; margin-bottom: 18px;
}
.glitch {
  font-size: clamp(30px, 6vw, 62px);
  font-weight: 800; letter-spacing: .04em; line-height: 1.05;
  text-transform: uppercase; margin: 0;
  color: #eaf4ff; position: relative; display: inline-block;
  text-shadow: 0 0 24px rgba(34,211,238,.25);
}
.glitch::before, .glitch::after {
  content: attr(data-text);
  position: absolute; left: 0; top: 0; width: 100%;
  clip-path: inset(0 0 0 0); opacity: .8;
}
.glitch::before { color: var(--pink); animation: gl1 3.4s infinite steps(2); }
.glitch::after  { color: var(--cyan); animation: gl2 2.7s infinite steps(2); }
@keyframes gl1 { 0%,92%,100%{transform:translate(0,0);clip-path:inset(0 0 100% 0)} 93%{transform:translate(-2px,1px);clip-path:inset(0 0 55% 0)} 96%{transform:translate(2px,-1px);clip-path:inset(40% 0 20% 0)} }
@keyframes gl2 { 0%,90%,100%{transform:translate(0,0);clip-path:inset(100% 0 0 0)} 91%{transform:translate(2px,-1px);clip-path:inset(60% 0 0 0)} 95%{transform:translate(-2px,1px);clip-path:inset(20% 0 50% 0)} }

.sub { color: var(--dim); max-width: 720px; margin: 18px auto 0; font-size: 14px; }
.sub b { color: var(--text); font-weight: 600; }

.progress-bar {
  margin: 30px auto 0; display: inline-flex; gap: 10px; align-items: center;
  padding: 9px 16px; border: 1px solid var(--line); border-radius: 999px;
  background: rgba(15,23,34,.6); font-size: 12px; color: var(--dim);
}
.progress-bar .dot { width: 11px; height: 11px; border-radius: 50%; border: 1px solid var(--line); background: #0a0f17; transition: .3s; }
.progress-bar .dot.done { background: var(--ok); border-color: var(--ok); box-shadow: 0 0 12px var(--ok); }
.progress-bar #count { color: var(--text); }

/* ---------- cards ---------- */
.grid { display: grid; grid-template-columns: 1fr; gap: 26px; margin-top: 48px; }
@media (min-width: 880px) { .grid { grid-template-columns: 1fr 1fr 1fr; } }

.card {
  --accent: var(--cyan);
  position: relative; background: linear-gradient(180deg, var(--panel) 0%, var(--bg2) 100%);
  border: 1px solid var(--line); border-radius: 14px; overflow: hidden;
  display: flex; flex-direction: column;
  transition: transform .25s, box-shadow .25s, border-color .25s;
}
.card:hover { transform: translateY(-4px); border-color: var(--accent); box-shadow: 0 18px 50px -20px var(--accent); }
.card.solved { border-color: var(--ok); box-shadow: 0 0 0 1px var(--ok), 0 18px 50px -22px var(--ok); }

.card .topglow { height: 3px; background: linear-gradient(90deg, transparent, var(--accent), transparent); opacity: .9; }

.art {
  height: 200px; display: flex; align-items: center; justify-content: center;
  background:
    radial-gradient(420px 220px at 50% 120%, color-mix(in srgb, var(--accent) 22%, transparent), transparent 70%),
    repeating-linear-gradient(135deg, rgba(255,255,255,.015) 0 8px, transparent 8px 16px);
  border-bottom: 1px solid var(--line);
}
.art svg { width: 168px; height: 168px; filter: drop-shadow(0 6px 16px rgba(0,0,0,.5)); }
.art svg .accent { color: var(--accent); }

.card .body { padding: 20px 20px 22px; display: flex; flex-direction: column; gap: 13px; flex: 1; }

.meta-row { display: flex; align-items: center; justify-content: space-between; gap: 10px; }
.brand { font-size: 11px; letter-spacing: .26em; text-transform: uppercase; color: var(--accent); }
.lvl { font-size: 10px; letter-spacing: .2em; color: var(--dim); border: 1px solid var(--line); border-radius: 4px; padding: 3px 7px; }
.model { font-size: 21px; font-weight: 800; color: #eef5ff; margin: -4px 0 0; letter-spacing: .01em; }
.category { font-size: 12px; color: var(--dim); margin-top: -6px; }

.tags { display: flex; flex-wrap: wrap; gap: 6px; }
.tag { font-size: 10px; letter-spacing: .08em; text-transform: uppercase; padding: 3px 8px; border-radius: 4px;
  background: color-mix(in srgb, var(--accent) 14%, transparent); color: var(--accent);
  border: 1px solid color-mix(in srgb, var(--accent) 35%, transparent); }
.tag.cve { background: rgba(255,84,112,.1); color: var(--danger); border-color: rgba(255,84,112,.4); }

.teaser { font-size: 13px; color: var(--dim); }

.linkbtn { background: none; border: none; color: var(--accent); cursor: pointer; font-family: var(--mono);
  font-size: 12px; padding: 0; text-align: left; letter-spacing: .04em; }
.linkbtn:hover { text-decoration: underline; }

.dl {
  display: flex; align-items: center; gap: 10px; text-decoration: none;
  border: 1px solid var(--line); border-radius: 8px; padding: 11px 13px;
  color: var(--text); background: var(--panel2); transition: .2s; font-size: 13px;
}
.dl:hover { border-color: var(--accent); background: #16273a; }
.dl .ic { color: var(--accent); }
.dl .fname { font-weight: 700; }
.dl .fsize { color: var(--dim); margin-left: auto; font-size: 11px; }
.dl .hint { display:block; color: var(--dim); font-size: 10.5px; margin-top: 2px; }

.solve label { font-size: 11px; letter-spacing: .14em; text-transform: uppercase; color: var(--dim); display:block; margin-bottom: 6px; }
.solve .ipt { display: flex; gap: 8px; }
.solve input {
  flex: 1; background: #080d14; border: 1px solid var(--line); border-radius: 7px;
  color: var(--text); padding: 11px 12px; font-family: var(--mono); font-size: 13px; outline: none;
}
.solve input:focus { border-color: var(--accent); box-shadow: 0 0 0 2px color-mix(in srgb, var(--accent) 25%, transparent); }
.solve button.go {
  background: var(--accent); color: #04121a; border: none; border-radius: 7px; padding: 0 16px;
  font-family: var(--mono); font-weight: 800; letter-spacing: .08em; cursor: pointer; font-size: 12px;
  text-transform: uppercase; transition: filter .15s;
}
.solve button.go:hover { filter: brightness(1.12); }
.solve button.go:disabled { opacity: .5; cursor: default; }

.status { font-size: 12.5px; min-height: 18px; letter-spacing: .03em; }
.status.err { color: var(--danger); }
.status.ok { color: var(--ok); }
.shake { animation: shake .4s; }
@keyframes shake { 0%,100%{transform:translateX(0)} 20%{transform:translateX(-8px)} 40%{transform:translateX(7px)} 60%{transform:translateX(-5px)} 80%{transform:translateX(4px)} }

.writeup-slot { border-top: 1px dashed var(--line); padding-top: 13px; margin-top: 2px; }
.locked { color: var(--dim); font-size: 12.5px; display: flex; align-items: center; gap: 8px; }
.unlocked { display: none; }
.card.solved .locked { display: none; }
.card.solved .unlocked { display: block; }

/* ---------- modal ---------- */
.modal-bg {
  position: fixed; inset: 0; background: rgba(3,6,10,.82); backdrop-filter: blur(4px);
  display: none; align-items: center; justify-content: center; z-index: 50; padding: 24px;
}
.modal-bg.open { display: flex; }
.modal {
  --accent: var(--cyan);
  background: linear-gradient(180deg, var(--panel) 0%, var(--bg2) 100%);
  border: 1px solid var(--accent); border-radius: 14px; max-width: 760px; width: 100%;
  max-height: 86vh; overflow: auto; box-shadow: 0 30px 80px -20px var(--accent);
}
.modal .mhead { position: sticky; top: 0; display: flex; align-items: center; justify-content: space-between;
  padding: 16px 22px; border-bottom: 1px solid var(--line); background: var(--panel);
  backdrop-filter: blur(2px); }
.modal .mhead .t { font-size: 13px; letter-spacing: .18em; text-transform: uppercase; color: var(--accent); }
.modal .x { background: none; border: 1px solid var(--line); color: var(--text); border-radius: 6px;
  width: 30px; height: 30px; cursor: pointer; font-size: 16px; line-height: 1; }
.modal .x:hover { border-color: var(--accent); }
.mcontent { padding: 22px 26px 30px; }
.mcontent h1, .mcontent h2 { color: #eaf4ff; letter-spacing: .01em; }
.mcontent h1 { font-size: 22px; margin-top: 0; }
.mcontent h2 { font-size: 15px; margin-top: 26px; border-left: 3px solid var(--accent); padding-left: 10px; }
.mcontent p, .mcontent li { color: var(--text); font-size: 14px; }
.mcontent code { background: #060b12; border: 1px solid var(--line); border-radius: 4px; padding: 1px 5px; color: var(--cyan); font-size: 12.5px; }
.mcontent pre { background: #060b12; border: 1px solid var(--line); border-radius: 8px; padding: 14px; overflow: auto; }
.mcontent pre code { border: none; background: none; padding: 0; color: #bfe9f4; }
.mcontent table { border-collapse: collapse; width: 100%; font-size: 13px; margin: 10px 0; }
.mcontent th, .mcontent td { border: 1px solid var(--line); padding: 6px 10px; text-align: left; }
.mcontent th { background: var(--panel2); color: var(--accent); }
.mcontent blockquote { border-left: 3px solid var(--accent); margin: 14px 0; padding: 6px 14px; color: var(--dim);
  background: rgba(255,255,255,.02); }
.mcontent .lead { color: var(--dim); font-size: 13px; letter-spacing: .04em; text-transform: uppercase; margin-bottom: 4px; }

/* fireworks overlay */
#fx { position: fixed; inset: 0; pointer-events: none; z-index: 60; }

footer { text-align: center; color: var(--dim); font-size: 12px; margin-top: 64px;
  border-top: 1px solid var(--line); padding-top: 30px; }
footer a { color: var(--cyan); text-decoration: none; }
footer a:hover { text-decoration: underline; }
.foot-logos { display: flex; align-items: center; justify-content: center; gap: 14px; margin-bottom: 16px; }
.foot-logos .logo { height: 40px; }
.credits { font-size: 13px; color: var(--text); line-height: 1.7; margin-bottom: 18px; }
.credits b { color: #eaf4ff; }
.banner { margin-top: 14px; font-size: 11px; color: #4a5a70; letter-spacing: .05em; }