/* ==========================================================================
   Variables & global reset
   ========================================================================== */
   *, *::before, *::after { box-sizing:border-box; margin:0; padding:0; }

   :root {
     /* Light */
     --clr-bg:#FCFCFD; --clr-fg:#111;
     --clr-accent:#6366F1; --clr-accent-2:#06B6D4;
     --clr-card-bg:#F1F5F9; --clr-card-fg:#111;
     --clr-muted:#4B5563;
     --shadow-soft:0 4px 12px rgba(0,0,0,.08);
     --shadow-hover:0 8px 18px rgba(0,0,0,.12);
   }
   
   [data-theme="dark"]{
     --clr-bg:#09090B; --clr-fg:#F3F4F6;
     --clr-accent:#818CF8; --clr-accent-2:#22D3EE;
     --clr-card-bg:#1F1F22; --clr-card-fg:#F3F4F6;
     --clr-muted:#9CA3AF;
     --shadow-soft:0 4px 12px rgba(0,0,0,.5);
     --shadow-hover:0 8px 18px rgba(0,0,0,.7);
   }
   
   html,body{height:100%;scroll-behavior:smooth;font-family:'Inter',sans-serif;}
   body{background:var(--clr-bg);color:var(--clr-fg);line-height:1.6;scroll-padding-top:4.2rem;padding-top:4.2rem;}
   .container{width:min(1200px,92%);margin-inline:auto;}
   a{color:var(--clr-accent);text-underline-offset:2px;} img,svg{max-width:100%;display:block;}
   button{border:none;cursor:pointer;background:none;color:inherit;}
   
   /* Header */
   .site-header{
     position:fixed;
     top:0;left:0;right:0;
     width:100%;
     margin-inline:0;
     padding-left:4%;
     padding-right:4%;
     display:flex; justify-content:space-between; align-items:center;
     padding:.9rem 0; transition:box-shadow .25s ease, background .25s ease;
     background:rgba(var(--clr-bg-rgb,252,252,253),.75);
     backdrop-filter:saturate(180%) blur(12px);
     z-index:50;
   }
   [data-theme="dark"] .site-header{background:rgba(9,9,11,.55);}
   .site-header[data-scrolled]{box-shadow:0 1px 4px rgba(0,0,0,.06);}

   .brand{display:flex;align-items:center;gap:.5rem;text-decoration:none;color:inherit}
   .brand svg{width:28px;height:28px}
   .brand__name{font-weight:900;letter-spacing:-.3px;font-size:1.15rem}

   .main-nav{display:flex;gap:1.2rem;align-items:center;}
   .main-nav a{position:relative;font-weight:600;text-decoration:none;}
   .main-nav a::after{content:'';position:absolute;inset-inline:0;bottom:-2px;height:2px;background:currentColor;transform:scaleX(0);transform-origin:left;transition:transform .2s;}
   .main-nav a:hover::after{transform:scaleX(1);}
   #themeToggle{font-size:1.1rem;line-height:0;}
   
   /* Hero */
   .hero{
     position:relative;
     padding:4.5rem 0 2.5rem;
     overflow:hidden;                 /* hide the off‑edge ring */
   }
   .hero__inner{position:relative;z-index:2;text-align:center;}
   .hero__title{font-size:clamp(2.8rem,7vw,4.8rem);font-weight:900;line-height:1.1;margin-bottom:.2em}
   .hero__name{background:linear-gradient(90deg,var(--clr-accent),var(--clr-accent-2));
               -webkit-background-clip:text;background-clip:text;color:transparent}
   .hero__dot{color:var(--clr-accent-2)}
   .hero__tagline{color:var(--clr-muted);font-size:1.05rem;margin:.7rem auto 2.4rem;max-width:600px}
   .hero__hi{font-weight:400;font-size:.7em}
   .hide-sm{display:none;}

   .ring{
     position:absolute;inset:-40vmax;          /* oversize so only arc shows */
     background:conic-gradient(from 120deg at 50% 50%,
                transparent 0deg,var(--clr-accent) 90deg,
                var(--clr-accent-2) 180deg,transparent 270deg);
     border-radius:50%;z-index:1;
     animation:spin 18s linear infinite;
     opacity:.15;pointer-events:none;
   }
   @keyframes spin{to{transform:rotate(1turn)}}
   
   /* Buttons */
   .btn,.btn-card{display:inline-block;padding:.7em 1.4em;border-radius:.45em;font-weight:600;text-decoration:none;transition:transform .15s,box-shadow .15s;background:var(--clr-accent);color:#fff;box-shadow:var(--shadow-soft);}
   .btn:hover{transform:translateY(-2px);box-shadow:var(--shadow-hover);}
   .btn--ghost{background:transparent;color:var(--clr-fg);border:2px solid var(--clr-accent);box-shadow:none;}
   .btn--ghost:hover{background:linear-gradient(135deg,var(--clr-accent),var(--clr-accent-2));color:#fff;transform:translateY(-2px);box-shadow:var(--shadow-hover);}
   .btn-card{margin-top:auto;background:var(--clr-fg);color:var(--clr-bg);}
   .card:hover .btn-card{background:var(--clr-accent);}
   
   /* Sections */
   .section-title{text-align:center;font-size:1.8rem;font-weight:800;margin-bottom:1.8rem;}
   
   /* Cards grid */
   .cards-grid{display:grid;gap:1.4rem;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));}
   .card{display:flex;flex-direction:column;padding:1.8rem 1.6rem;border-radius:.8rem;background:var(--clr-card-bg);color:var(--clr-card-fg);box-shadow:var(--shadow-soft);transition:.2s;}
   .card:hover{transform:translateY(-4px);box-shadow:var(--shadow-hover);}
   .card h4{font-size:1.3rem;font-weight:800;}
   .card .tagline{color:var(--clr-muted);margin-bottom:.8rem;}
   .card ul{list-style:disc;margin-left:1.1rem;flex-grow:1;font-size:.93rem;}
   .card li+li{margin-top:.35rem;}
   .card--tutor,
   .card--tutorist,
   .card--twopeas{border-top:none;}
   
   /* Research */
   .research{padding:4.5rem 0;text-align:center;}
   .table-scroll{overflow-x:auto;margin-top:.6rem;}
   pre{font-family:Menlo,monospace;font-size:.85rem;background:var(--clr-card-bg);padding:1rem;border-radius:.6rem;}
   .note{color:var(--clr-muted);font-size:.9rem;margin-top:.6rem;}
   .research-inner{display:flex;flex-direction:column;gap:2rem;align-items:center;justify-content:space-between;}
   .research-text{flex:1 1 300px;max-width:540px;}
   .research-media{flex:1 1 320px;max-width:550px;}
   .research p{max-width:760px;margin-inline:auto;}
   .research figure{margin:0;}
   @media(min-width:700px){
     .research-inner{flex-direction:row;align-items:center;gap:3rem;text-align:left;}
     .research p{text-align:left;margin-inline:0;}
   }
   .research figure{margin-top:0;margin-inline:auto;text-align:center;}
   .research img{width:100%;max-width:550px;height:auto;border-radius:.6rem;box-shadow:var(--shadow-soft);margin-inline:auto;}
   .research-note{margin-top:1rem;font-size:.9rem;line-height:1.5;color:var(--clr-muted);}
   .research-note__title{font-size:1rem;font-weight:700;margin-bottom:.5rem;color:var(--clr-fg);}
   .research-note ul{padding-left:1.2rem;margin-top:.6rem;margin-bottom:.6rem;}
   .research-note li{margin-bottom:.35rem;}
   
   /* CV */
   .cv{padding:4.5rem 0;}
   .cv-grid{display:grid;gap:2rem;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));margin-bottom:2.5rem;max-width:740px;margin-inline:auto;}
   .cv-grid h4{margin-bottom:.6rem;font-size:1.15rem;font-weight:700;}
   .cv-grid ul{padding-left:1.2rem;}
   .cv-card ul li{margin-bottom:.35rem;}
   .timeline{max-width:600px;margin-inline:auto;list-style:none;border-left:2px solid var(--clr-accent);padding-left:1rem;}
   .timeline li{position:relative;padding:.6rem 0 .6rem .4rem;}
   .timeline li span{display:block;font-weight:600;margin-bottom:.15rem;color:var(--clr-accent);}
   .cv-card{background:var(--clr-card-bg);padding:1.4rem 1.2rem;border-radius:.6rem;box-shadow:var(--shadow-soft);}
   
   /* Contact & footer */
   .contact{padding:4.5rem 0;}
   .site-footer{text-align:center;padding:1.4rem 0;color:var(--clr-muted);font-size:.85rem;border-top:1px solid rgba(0,0,0,.05);}
   
   /* CV layout enhancements */
   .cv-inner{display:flex;flex-direction:column;gap:2.5rem;margin-top:2rem;}
   .cv-skills{width:100%;}
   .cv-timeline{background:var(--clr-card-bg);padding:1.6rem 1.4rem;border-radius:.6rem;box-shadow:var(--shadow-soft);}
   .timeline{border-color:var(--clr-accent);margin-top:.5rem;}
   .timeline li{font-size:.93rem;line-height:1.45;position:relative;}
   .timeline li+li{margin-top:.8rem;}
   .timeline-title{text-align:center;font-size:1.25rem;font-weight:800;margin-bottom:1rem;}
   .cv-card,.cv-timeline{display:flex;flex-direction:column;justify-content:flex-start;}
   .cv-grid{display:grid;gap:1.8rem;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));margin-bottom:0;max-width:none;margin-inline:0;}
   
   @media(min-width:900px){
     .cv-inner{flex-direction:row;align-items:flex-start;}
     .cv-skills{flex:1 1 60%;}
     .cv-timeline{flex:0 0 360px;position:sticky;top:6rem;}
     .cv-grid{grid-template-columns:repeat(auto-fill,minmax(280px,1fr));}
   }
   
   /* ---------- Responsive nuance ---------- */
   @media (min-width:900px) {
     .hero { padding:6rem 0 3.5rem; }
   }
   
   @media (min-width:700px) {
     .hide-sm { display:inline; }
   }
   
   /* ───── Final touches: full-width header & prettier CTA buttons ───── */
   
   /* Nicer call-to-action layout */
   .hero__cta{
     display:flex;
     justify-content:center;
     gap:1rem;
     flex-wrap:wrap;
   }
   
   /* round pill buttons */
   .hero__cta .btn,
   .hero__cta .btn--ghost{border-radius:9999px;}
   
   /* make both buttons equal width for perfect centering despite text length */
   .hero__cta a{
     min-width:11rem;      /* enough for the longer label */
     text-align:center;
     flex:0 0 11rem;       /* fixed width to balance visual weight */
   }
   
   /* Upsized & gradient buttons */
   .btn,
   .btn-card{
     padding:.9em 1.8em;
     font-size:1.05rem;
   }
   
   .btn{
     background:linear-gradient(135deg,var(--clr-accent),var(--clr-accent-2));
   }
   
   /* ensure AI card surfaces first */
   .cv-card--ai{order:-1;}
   
   @media(min-width:700px){
     /* Let AI card occupy ~2/3 width when grid has ≥3 columns */
     .cv-card--ai{grid-column:span 2;}
   }