:root{--casio:#003b7a;--blue:#075baa;--sky:#eaf5ff;--ink:#162332;--muted:#637181;--line:#dce5ed;--yellow:#f7c843;--success:#147a51;--danger:#b73838}*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;color:var(--ink);background:#fff;font-family:Inter,"Noto Sans Thai",Arial,sans-serif}.wrap{width:min(1160px,calc(100% - 48px));margin:auto}.utility{background:#f3f6f8;color:#607080;font-size:12px}.utility-inner{height:30px;display:flex;justify-content:flex-end;align-items:center;gap:28px}.nav-row{height:76px;display:flex;align-items:center;gap:56px}.brand{font-size:24px;font-weight:800;text-decoration:none;color:var(--casio);letter-spacing:-1px}.brand span{color:#e72e42}.nav-row nav{display:flex;gap:34px;flex:1}.nav-row nav a{color:#314253;text-decoration:none;font-size:14px;font-weight:600}.lang{border:1px solid var(--line);background:white;border-radius:6px;padding:10px 14px;font-weight:700;color:var(--ink)}.hero{background:linear-gradient(115deg,#e9f5ff 0%,#f7fbff 55%,#e3f1fb 100%);overflow:hidden}.hero-grid{min-height:410px;display:grid;grid-template-columns:1.05fr .95fr;align-items:center;gap:50px}.eyebrow{font-size:12px;font-weight:800;letter-spacing:1.8px;color:#2667a1;margin:0 0 14px}.hero h1{font-size:50px;line-height:1.08;margin:0 0 20px;letter-spacing:-2px;color:#11314f}.hero h1 span{color:var(--blue)}.hero-copy{font-size:17px;line-height:1.7;color:#546779;max-width:570px;margin:0 0 28px}.primary,.secondary{display:inline-flex;align-items:center;justify-content:center;gap:18px;border-radius:5px;padding:14px 22px;font:700 14px Inter;text-decoration:none;cursor:pointer}.primary{background:var(--blue);border:1px solid var(--blue);color:#fff}.primary:hover{background:#034985}.secondary{background:#fff;border:1px solid #aebdca;color:#23415e}.secondary:disabled{opacity:.45;cursor:not-allowed}.math-visual{height:330px;position:relative}.formula{position:absolute;color:#1d5d94;font-family:Georgia,serif;font-style:italic}.f1{top:35px;right:38px;font-size:21px}.f2{bottom:32px;left:32px;font-size:18px}.f3{top:84px;left:35px;font-size:38px}.graph-card{position:absolute;width:310px;height:215px;right:55px;top:80px;background:rgba(255,255,255,.82);border:1px solid #c7dfef;border-radius:12px;box-shadow:0 18px 45px rgba(18,70,110,.13);transform:rotate(-2deg);overflow:hidden}.grid-lines{position:absolute;inset:0;background-image:linear-gradient(#dcecf5 1px,transparent 1px),linear-gradient(90deg,#dcecf5 1px,transparent 1px);background-size:28px 28px}.graph-card svg{position:absolute;inset:14px;width:calc(100% - 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