*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;text-rendering:optimizeLegibility}
:root{
  /* Main-page palette */
  --bg:#0b1220;--bg2:#0b1220;
  --surface:rgba(255,255,255,.03);--surface2:rgba(255,255,255,.05);--surface3:rgba(255,255,255,.06);
  --border:#243246;--border2:#334155;--border3:#263247;
  --text:#e6edf3;--text-muted:#9fb2c9;--text-dim:#9fb2c9;
  --blue:#3b82f6;--blue2:#60a5fa;--blue3:#93c5fd;
  --green:#10b981;--green2:#34d399;
  --yellow:#f59e0b;--yellow2:#fbbf24;
  --red:#ef4444;--red2:#f87171;
  --purple:#8b5cf6;--purple2:#a78bfa;
  --font:system-ui,-apple-system,Segoe UI,Roboto,Ubuntu,Helvetica,Arial,sans-serif;
  --font-humanist:'Nunito Sans','Segoe UI','Gill Sans','Frutiger','Myriad Pro',Arial,sans-serif;
  --mono:'IBM Plex Mono',monospace;
}
html{font-size:16px;scroll-behavior:smooth}
body{background:var(--bg);color:var(--text);font-family:var(--font);line-height:1.5;min-height:100vh}
a{color:var(--blue2);text-decoration:none}
a:hover{color:var(--blue3)}

/* NAV */
.site-nav{
  position:sticky;top:0;z-index:200;
  background:rgba(11,18,32,0.88);
  backdrop-filter:blur(16px);-webkit-backdrop-filter:blur(16px);
  border-bottom:1px solid var(--border);
}
.nav-inner{
  max-width:1200px;
  margin:0 auto;
  height:68px;
  padding:0 24px;
  display:flex;align-items:center;justify-content:space-between;
}
.nav-logo{display:flex;align-items:center;gap:10px;font-size:16px;font-weight:800;color:var(--text);letter-spacing:.02em}
.nav-logo:hover{color:var(--text)}
.nav-logo-icon{display:flex;align-items:center;justify-content:center;width:38px;height:38px;background:transparent;border-radius:8px;border:none;box-shadow:none}
.nav-logo-text{position:relative;top:0.5px}
.nav-links{display:flex;align-items:center;gap:6px}
.nav-links a{font-size:15px;font-weight:600;color:var(--text-muted);padding:8px 12px;border-radius:8px;transition:color .15s,background .15s}
.nav-links a:hover{color:var(--text);background:var(--surface)}
.nav-link-muted{opacity:.8}

/* Mobile hamburger */
.nav-toggle{display:none;align-items:center;justify-content:center;width:48px;height:44px;border-radius:10px;border:1px solid var(--border);background:var(--surface);color:var(--text);cursor:pointer}
.nav-toggle:hover{border-color:var(--border2);background:var(--surface2)}
.nav-toggle-bars{position:relative;display:block;width:18px;height:2px;background:currentColor;border-radius:2px}
.nav-toggle-bars::before,.nav-toggle-bars::after{content:"";position:absolute;left:0;width:18px;height:2px;background:currentColor;border-radius:2px}
.nav-toggle-bars::before{top:-6px}
.nav-toggle-bars::after{top:6px}

.nav-drawer{
  max-width:1200px;
  margin:0 auto;
  padding:10px 24px 14px;
  border-top:1px solid var(--border);
}
.nav-drawer a{display:block;font-size:14px;padding:16px 14px;border-radius:12px;color:var(--text);font-weight:700}
.nav-drawer a:hover{background:var(--surface2)}

/* PAGE */
.page{max-width:1200px;margin:0 auto;padding:32px 24px 96px}

/* HEADER */
.page-header{margin-bottom:40px}
.page-header-inner{
  display:flex;align-items:flex-end;justify-content:space-between;
  gap:24px;flex-wrap:wrap;padding-bottom:28px;
  border-bottom:1px solid var(--border);
}
.page-header-eyebrow{
  font-family:var(--mono);font-size:12px;letter-spacing:.16em;
  text-transform:uppercase;color:var(--blue2);margin-bottom:10px;opacity:.8;
}
.page-header h1{font-family:var(--font-humanist);font-size:clamp(30px,4.2vw,48px);font-weight:800;color:var(--text);letter-spacing:-.02em;line-height:1.1}
.page-header p{font-size:16px;color:var(--text-muted);margin-top:8px;font-weight:500;max-width:520px}
.stat-row{display:flex;gap:24px;flex-shrink:0}
.stat{text-align:right}
.stat-val{font-family:var(--mono);font-size:26px;font-weight:600;color:var(--text);line-height:1}
.stat-label{font-size:12px;color:var(--text-muted);text-transform:uppercase;letter-spacing:.1em;margin-top:4px}

/* FILTER */
.filter-bar{display:flex;flex-wrap:wrap;gap:6px;margin-bottom:36px}
.filter-btn{
  font-family:var(--font);font-size:12.5px;font-weight:500;
  padding:6px 14px;border-radius:6px;border:1px solid var(--border);
  background:var(--surface);color:var(--text);cursor:pointer;
  transition:all .15s;letter-spacing:.01em;
  display:flex;align-items:center;gap:6px;
}
.filter-btn:hover{border-color:var(--border2);color:var(--text);background:var(--surface2)}
.filter-btn.active{background:rgba(59,130,246,.13);border-color:rgba(59,130,246,.38);color:var(--blue2)}
.filter-btn.active[data-filter="vol"]{background:rgba(245,158,11,.1);border-color:rgba(245,158,11,.35);color:var(--yellow2)}
.filter-btn.active[data-filter="timing"]{background:rgba(16,185,129,.1);border-color:rgba(16,185,129,.35);color:var(--green2)}
.filter-btn.active[data-filter="struct"]{background:rgba(139,92,246,.1);border-color:rgba(139,92,246,.35);color:var(--purple2)}
.filter-btn.active[data-filter="risk"]{background:rgba(239,68,68,.1);border-color:rgba(239,68,68,.35);color:var(--red2)}
.filter-btn.active[data-filter="strategy"]{background:rgba(96,165,250,.1);border-color:rgba(96,165,250,.35);color:var(--blue3)}
.filter-btn.active[data-filter="basics"]{background:rgba(100,120,150,.1);border-color:rgba(100,120,150,.35);color:var(--text)}
.filter-dot{width:5px;height:5px;border-radius:50%;background:currentColor;opacity:.7}

/* SECTION */
.section{margin-top:40px}
.section:first-of-type{margin-top:0}
.section-title{
  display:flex;align-items:center;gap:12px;
  font-family:var(--mono);font-size:11px;font-weight:500;
  text-transform:uppercase;letter-spacing:.15em;color:var(--text-dim);margin-bottom:14px;
}
.section-title::after{content:'';flex:1;height:1px;background:linear-gradient(90deg,var(--border) 0%,transparent 100%)}
.section-num{font-family:var(--mono);font-size:10px;color:var(--text-dim);opacity:.5}

/* GRID */
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(290px,1fr));gap:14px}

/* CARD */
.card{
  background:var(--surface);border:1px solid var(--border);border-radius:10px;
  padding:22px 22px 20px 26px;
  display:flex;flex-direction:column;gap:14px;
  position:relative;overflow:hidden;
  transition:transform .2s ease,box-shadow .2s ease,border-color .2s ease,background .2s ease;
  cursor:default;
  opacity:0;animation:cardIn .4s ease forwards;
}
.card:nth-child(1){animation-delay:.04s}
.card:nth-child(2){animation-delay:.08s}
.card:nth-child(3){animation-delay:.12s}
.card:nth-child(4){animation-delay:.16s}
.card:nth-child(5){animation-delay:.2s}
.card:nth-child(6){animation-delay:.24s}
@keyframes cardIn{from{opacity:0;transform:translateY(10px)}to{opacity:1;transform:translateY(0)}}
.card::before{
  content:'';position:absolute;top:14px;left:0;bottom:14px;
  width:3px;border-radius:0 2px 2px 0;transition:opacity .2s;
}
.card::after{
  content:'';position:absolute;inset:0;
  opacity:0;transition:opacity .25s;pointer-events:none;border-radius:10px;
}
.card:hover{transform:translateY(-3px);border-color:var(--border2);background:var(--surface2)}
.card:hover::after{opacity:1}

.card.basics::before{background:var(--text-dim)}
.card.basics:hover{box-shadow:0 10px 36px rgba(0,0,0,.4)}
.card.basics::after{box-shadow:inset 0 1px 0 rgba(120,140,170,.08)}

.card.greek::before{background:linear-gradient(180deg,var(--blue2),var(--blue))}
.card.greek:hover{box-shadow:0 10px 36px rgba(0,0,0,.4),0 0 0 1px rgba(59,130,246,.1) inset}
.card.greek::after{box-shadow:inset 0 1px 0 rgba(59,130,246,.14)}

.card.vol::before{background:linear-gradient(180deg,var(--yellow2),var(--yellow))}
.card.vol:hover{box-shadow:0 10px 36px rgba(0,0,0,.4),0 0 0 1px rgba(245,158,11,.09) inset}
.card.vol::after{box-shadow:inset 0 1px 0 rgba(245,158,11,.12)}

.card.timing::before{background:linear-gradient(180deg,var(--green2),var(--green))}
.card.timing:hover{box-shadow:0 10px 36px rgba(0,0,0,.4),0 0 0 1px rgba(16,185,129,.09) inset}
.card.timing::after{box-shadow:inset 0 1px 0 rgba(16,185,129,.12)}

.card.struct::before{background:linear-gradient(180deg,var(--purple2),var(--purple))}
.card.struct:hover{box-shadow:0 10px 36px rgba(0,0,0,.4),0 0 0 1px rgba(139,92,246,.09) inset}
.card.struct::after{box-shadow:inset 0 1px 0 rgba(139,92,246,.12)}

.card.risk::before{background:linear-gradient(180deg,var(--red2),var(--red))}
.card.risk:hover{box-shadow:0 10px 36px rgba(0,0,0,.4),0 0 0 1px rgba(239,68,68,.09) inset}
.card.risk::after{box-shadow:inset 0 1px 0 rgba(239,68,68,.12)}

.card.strategy::before{background:linear-gradient(180deg,var(--blue3),var(--blue2))}
.card.strategy:hover{box-shadow:0 10px 36px rgba(0,0,0,.4),0 0 0 1px rgba(96,165,250,.09) inset}
.card.strategy::after{box-shadow:inset 0 1px 0 rgba(96,165,250,.12)}

/* CARD HEAD */
.card-head{display:flex;align-items:flex-start;justify-content:space-between;gap:10px}
.card-title{font-size:16.5px;font-weight:600;color:var(--text);letter-spacing:-.015em;line-height:1.25}

/* BADGE */
.badge{
  flex-shrink:0;font-family:var(--mono);font-size:10px;font-weight:500;
  letter-spacing:.08em;text-transform:uppercase;
  padding:3px 9px;border-radius:5px;border:1px solid;white-space:nowrap;margin-top:1px;
}
.badge.basics{color:var(--text);border-color:rgba(100,120,150,.25);background:rgba(100,120,150,.07)}
.badge.greek{color:var(--blue2);border-color:rgba(59,130,246,.3);background:rgba(59,130,246,.07)}
.badge.vol{color:var(--yellow2);border-color:rgba(245,158,11,.3);background:rgba(245,158,11,.07)}
.badge.timing{color:var(--green2);border-color:rgba(16,185,129,.3);background:rgba(16,185,129,.07)}
.badge.struct{color:var(--purple2);border-color:rgba(139,92,246,.3);background:rgba(139,92,246,.07)}
.badge.risk{color:var(--red2);border-color:rgba(239,68,68,.3);background:rgba(239,68,68,.07)}
.badge.strategy{color:var(--blue3);border-color:rgba(96,165,250,.3);background:rgba(96,165,250,.07)}

/* BULLETS */
.bullets{display:flex;flex-direction:column;gap:6px}
.bullets li{
  list-style:none;display:flex;align-items:baseline;gap:8px;
  font-size:13.75px;color:var(--text);line-height:1.5;font-weight:450;
}
.bullet-dot{width:4px;height:4px;border-radius:50%;flex-shrink:0;margin-top:5px;opacity:.85}
.card.basics .bullet-dot{background:var(--text)}
.card.greek .bullet-dot{background:var(--blue2)}
.card.vol .bullet-dot{background:var(--yellow2)}
.card.timing .bullet-dot{background:var(--green2)}
.card.struct .bullet-dot{background:var(--purple2)}
.card.risk .bullet-dot{background:var(--red2)}
.card.strategy .bullet-dot{background:var(--blue3)}

/* RULE */
.rule{border:none;border-top:1px solid var(--border);margin:0}

/* DESC */
.card-desc{font-size:13.5px;line-height:1.75;color:var(--text);font-weight:450;letter-spacing:.005em}

/* WATERMARK */
.sym{
  position:absolute;bottom:12px;right:16px;
  font-family:var(--mono);font-size:34px;font-weight:500;
  opacity:.03;user-select:none;pointer-events:none;line-height:1;
  color:var(--text);letter-spacing:-.02em;
}

.card.hidden{display:none}

/* FOOTER */
footer{
  max-width:1200px;margin:72px auto 0;padding:28px 24px;
  border-top:1px solid var(--border);
  display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:12px;
}
.footer-left{font-size:14px;color:var(--text-dim)}
.footer-left a{color:var(--text-muted)}
.footer-left a:hover{color:var(--text)}
.footer-right{font-family:var(--mono);font-size:11px;color:var(--text-dim);letter-spacing:.08em}


/* RESPONSIVE */
@media(max-width:640px){
  .nav-inner{padding:0 16px}
  .page{padding:24px 16px 72px}
  .page-header h1{font-size:clamp(26px,7vw,36px)}
  .stat-row{display:none}
  .grid{grid-template-columns:1fr}
  footer{flex-direction:column;align-items:flex-start;gap:8px;padding:20px 16px}
}

@media(max-width:820px){
  .nav-links{display:none}
  .nav-toggle{display:flex}
}

.nav-logo-img{width:38px;height:38px;display:block}

/* ── Shared components (tool-card, disclaimer, help) ── */
.tool-card{
  background:rgba(255,255,255,.025);
  border:1px solid var(--border);
  border-radius:12px;
  padding:24px 28px;
  position:relative;
  overflow:hidden;
  margin-bottom:16px;
}
.tool-card::before{
  content:'';position:absolute;left:0;top:0;bottom:0;width:4px;
  background:var(--blue2);border-radius:0;
}
.tool-card h2{
  font-family:var(--font-humanist);font-size:20px;font-weight:800;
  color:var(--text);letter-spacing:-.01em;line-height:1.2;
}
details.help{margin-top:16px;border:1px dashed rgba(36,50,70,.8);border-radius:10px;padding:12px 16px}
details.help[open]{background:rgba(255,255,255,.015)}
details.help summary{font-size:14px;font-weight:600;color:var(--text-muted);cursor:pointer;list-style:none;display:flex;align-items:center;gap:8px}
details.help summary::marker,details.help summary::-webkit-details-marker{display:none}
details.help summary::before{content:"▸";font-size:11px;transition:transform .15s;display:inline-block}
details.help[open] summary::before{transform:rotate(90deg)}
details.help .help-body{margin-top:12px;padding-left:4px}
details.help ul{margin:0;padding:0 0 0 18px;display:flex;flex-direction:column;gap:8px}
details.help li{font-size:14px;color:var(--text-muted);line-height:1.6}
.disclaimer{
  margin-top:20px;padding:14px 18px;border-radius:8px;
  background:rgba(255,255,255,.02);border:1px solid rgba(36,50,70,.6);
  font-size:14px;color:var(--text-muted);line-height:1.6;
}
.disclaimer strong{color:rgba(251,191,36,.85)}

/* Tool card */
.tool-card{
  background:rgba(255,255,255,.025);
  border:1px solid var(--border);
  border-radius:12px;
  padding:24px 28px;
  position:relative;
  overflow:hidden;
  margin-bottom:16px;
}
.tool-card::before{
  content:"";position:absolute;left:0;top:0;bottom:0;width:4px;
  background:var(--blue2);border-radius:0;
}
.tool-card h2{
  font-family:var(--font-humanist);font-size:20px;font-weight:800;
  color:var(--text);letter-spacing:-.01em;line-height:1.2;
}

/* Help accordion */
details.help{margin-top:16px;border:1px dashed rgba(36,50,70,.8);border-radius:10px;padding:12px 16px}
details.help[open]{background:rgba(255,255,255,.015)}
details.help summary{font-size:14px;font-weight:600;color:var(--text-muted);cursor:pointer;list-style:none;display:flex;align-items:center;gap:8px}
details.help summary::marker,details.help summary::-webkit-details-marker{display:none}
details.help summary::before{content:"▸";font-size:11px;transition:transform .15s;display:inline-block}
details.help[open] summary::before{transform:rotate(90deg)}
details.help .help-body{margin-top:12px;padding-left:4px}
details.help ul{margin:0;padding:0 0 0 18px;display:flex;flex-direction:column;gap:8px}
details.help li{font-size:14px;color:var(--text-muted);line-height:1.6}

/* Disclaimer */
.disclaimer{
  margin-top:20px;padding:14px 18px;border-radius:8px;
  background:rgba(255,255,255,.02);border:1px solid rgba(36,50,70,.6);
  font-size:14px;color:var(--text-muted);line-height:1.6;
}
.disclaimer strong{color:rgba(251,191,36,.85)}