:root{--ink:#172033;--blue:#3157d5;--soft:#f4f7ff}body{color:var(--ink);background:#f8fafc}.site-nav{background:linear-gradient(90deg,#111827,#243b78)}.activity-banner{background:linear-gradient(135deg,#eef3ff,#fff);border-bottom:1px solid #dce4fb}.activity-banner .badge{letter-spacing:.08em}.activity-card{border:0;border-radius:18px;box-shadow:0 10px 30px rgba(30,50,100,.08)}.chapter-section{border-radius:18px;background:#fff;box-shadow:0 8px 24px rgba(15,23,42,.06)}.embed-frame{width:100%;min-height:72vh;border:0;border-radius:16px;background:#fff}.metric{border-radius:16px;background:#fff;box-shadow:0 8px 20px rgba(15,23,42,.06);padding:18px}.table thead th{white-space:nowrap}.form-select,.form-control{border-radius:10px}.btn{border-radius:10px}.chapter-hero{background:linear-gradient(135deg,#edf2ff,#f9fbff)}

/* ===== 2026 interface refresh ===== */
:root{--navy:#0d2034;--navy2:#15354a;--coral:#ff805f;--cream:#f7f3ed;--ink:#10213a;--muted:#667085}
body{font-family:Inter,"Segoe UI",Arial,sans-serif;color:var(--ink);background:#f8fafc}.site-nav{background:#0d2034!important;min-height:64px;border-bottom:1px solid rgba(255,255,255,.08)}.site-nav .navbar-brand{letter-spacing:.03em}.site-nav .nav-link{font-size:.92rem;color:rgba(255,255,255,.78)!important}.site-nav .nav-link:hover{color:#fff!important}.dropdown-menu{border:0;border-radius:14px;box-shadow:0 18px 45px rgba(15,23,42,.16);padding:.6rem}.dropdown-item{border-radius:9px;padding:.65rem .8rem}
.py-lg-6{padding-top:5.5rem!important;padding-bottom:5.5rem!important}.home-hero{background:radial-gradient(circle at 85% 30%,rgba(25,160,172,.25),transparent 35%),linear-gradient(120deg,#0d2034,#0d2439 65%,#123f4a);overflow:hidden}.eyebrow,.section-kicker{font-size:.72rem;font-weight:900;letter-spacing:.15em;color:var(--coral)}.home-hero h1{line-height:.92;letter-spacing:-.05em}.home-hero h1 span{color:var(--coral)}.hero-copy{color:#d6e1ec;font-size:1.08rem;max-width:610px}.btn-coral{background:var(--coral);border-color:var(--coral);color:#fff;font-weight:700}.btn-coral:hover{background:#f26e4d;border-color:#f26e4d;color:#fff}.hero-meta{display:flex;flex-wrap:wrap;gap:10px}.hero-meta span{font-size:.72rem;color:#dbe7ef;border:1px solid rgba(255,255,255,.16);border-radius:999px;padding:.4rem .7rem}.hero-visual{position:relative;background:#18344d;border:1px solid rgba(255,255,255,.14);border-radius:28px;padding:20px;box-shadow:0 30px 70px rgba(0,0,0,.25)}.hero-visual img{width:100%;aspect-ratio:16/10;object-fit:cover;border-radius:18px}.floating-code,.floating-ui{position:absolute;width:58px;height:58px;border-radius:16px;display:grid;place-items:center;font-weight:900;box-shadow:0 14px 35px rgba(0,0,0,.2)}.floating-code{right:-14px;top:38px;background:#fff;color:#3157d5}.floating-ui{left:-18px;bottom:36px;background:var(--coral);color:#fff}
.section-soft{background:var(--cream)}.section-heading{max-width:760px}.section-heading p{color:var(--muted)}.feature-card,.tool-card,.chapter-card{background:#fff;border:1px solid #e8e3dc;border-radius:18px;box-shadow:0 12px 35px rgba(31,41,55,.06)}.feature-card{padding:25px}.feature-card h3{font-size:1rem;font-weight:800}.feature-card p{font-size:.9rem;color:var(--muted);margin:0}.feature-icon{width:42px;height:42px;border-radius:12px;background:#edf6ff;color:#1769aa;display:grid;place-items:center;font-weight:900;margin-bottom:18px}.tool-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:15px}.tool-card{padding:20px;display:flex;flex-direction:column}.tool-card strong{font-size:.98rem}.tool-card span{font-size:.82rem;color:var(--muted);margin-top:3px}.chapter-card{position:relative;display:block;height:100%;padding:24px;text-decoration:none;color:var(--ink);overflow:hidden;transition:.22s}.chapter-card:hover{transform:translateY(-5px);box-shadow:0 20px 48px rgba(31,41,55,.12);color:var(--ink)}.chapter-number{display:inline-grid;place-items:center;width:42px;height:42px;border-radius:13px;font-size:.78rem;font-weight:900}.chapter-symbol{position:absolute;right:24px;top:24px;font-size:1.25rem;font-weight:800}.chapter-card h3{font-size:1.08rem;font-weight:850;margin-top:24px}.chapter-card p{font-size:.87rem;color:var(--muted);min-height:82px}.chapter-card span{font-size:.82rem;font-weight:800}.chapter-card-blue .chapter-number{background:#eaf6fb;color:#19709c}.chapter-card-blue span,.chapter-card-blue .chapter-symbol{color:#19709c}.chapter-card-coral .chapter-number{background:#fff0ed;color:#df5537}.chapter-card-coral span,.chapter-card-coral .chapter-symbol{color:#df5537}.chapter-card-purple .chapter-number{background:#f1eafe;color:#7542ca}.chapter-card-purple span,.chapter-card-purple .chapter-symbol{color:#7542ca}.learning-path{background:linear-gradient(110deg,#10233b,#203e68)}
.chapter-hero{position:relative;overflow:hidden;border-bottom:1px solid rgba(15,23,42,.08);background:linear-gradient(120deg,#edf3ff,#f8fbff)}.chapter-hero:after{content:"";position:absolute;width:280px;height:280px;border-radius:50%;right:-80px;top:-130px;background:rgba(49,87,213,.10)}.chapter-hero--2{background:linear-gradient(120deg,#fff3ec,#fffaf7)}.chapter-hero--2:after{background:rgba(255,128,95,.12)}.chapter-hero--3{background:linear-gradient(120deg,#f3efff,#fbfaff)}.chapter-hero--3:after{background:rgba(117,66,202,.12)}.chapter-hero h1{font-size:clamp(2rem,4vw,3.3rem);letter-spacing:-.035em}.chapter-section,.card{border-radius:18px}.list-group-item{padding:1rem;border-color:#edf0f4}.activity-banner{background:linear-gradient(135deg,#eef3ff,#fff);padding:1rem 0}.activity-banner h1{text-transform:none}
@media(max-width:767px){.home-hero h1{font-size:3rem}.tool-grid{grid-template-columns:1fr}.hero-visual{margin-top:8px}.site-nav{min-height:58px}}
/* ===== Banner colour synchronised with the supplied DFK20013 artwork ===== */
:root{--banner-deep:#05052f;--banner-blue:#20268f;--banner-violet:#4239b8;--banner-cyan:#32d9ff;--banner-pink:#ee75c9}
.home-hero{background:radial-gradient(circle at 78% 15%,rgba(50,217,255,.20),transparent 27%),radial-gradient(circle at 80% 92%,rgba(238,117,201,.18),transparent 31%),linear-gradient(125deg,var(--banner-deep),#11145d 52%,#29248d)!important}
.home-hero h1 span{color:#8deaff}.btn-coral{background:linear-gradient(135deg,#3f7cff,#6b46e8);border:0}.btn-coral:hover{background:linear-gradient(135deg,#326ce8,#5935d1)}
.hero-visual{background:linear-gradient(145deg,rgba(58,65,190,.55),rgba(5,5,47,.9));border-color:rgba(80,220,255,.35);box-shadow:0 30px 70px rgba(2,4,45,.48)}
.floating-ui{background:linear-gradient(135deg,#36d8ff,#6a50ed)}.learning-path{background:linear-gradient(110deg,#070733,#20268f 58%,#4b35a8)}
.student-gate{max-width:780px;margin:0 auto;background:#fff;border:1px solid #e7eaf3;border-radius:26px;padding:clamp(24px,4vw,42px);box-shadow:0 24px 55px rgba(15,23,42,.12)}
.student-gate h2{color:#593de4}.student-gate-icon{display:grid;place-items:center;width:54px;height:54px;border-radius:17px;background:#eeeaff;margin:0 auto 14px;font-size:1.45rem}
.quiz-shell{background:#f5f7fb;min-height:calc(100vh - 64px)}.quiz-top{background:linear-gradient(120deg,#3049bd,#6533de);color:#fff;padding:34px 0}.quiz-question{display:none}.quiz-question.active{display:block}.quiz-progress{height:10px;border-radius:999px}.answer-option{border:1px solid #e1e5ef;border-radius:14px;padding:14px 16px;margin-bottom:10px;cursor:pointer}.answer-option:has(input:checked){border-color:#6344df;background:#f2efff}