*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{font-family:-apple-system, 'Segoe UI', Roboto, Arial, sans-serif;background:#FFFFFF;color:#1D2B3A;line-height:1.7;font-size:16px}
img,svg{max-width:100%;height:auto;display:block}
a{color:#1F6FEB;text-decoration:none}
a:hover{text-decoration:underline}
ul,ol{padding-left:1.3em}
li{margin:.35em 0}
h1,h2,h3,h4{line-height:1.25;font-family:'Segoe UI', 'Helvetica Neue', Arial, sans-serif}
.container{width:100%;max-width:1160px;margin:0 auto;padding:0 20px}
.skip{position:absolute;left:-9999px}
.badge18{display:inline-block;font-size:11px;font-weight:700;letter-spacing:.5px;border:1.5px solid #7FD1F5;color:#7FD1F5;border-radius:999px;padding:1px 9px}
.tbl-wrap{overflow-x:auto;margin:1.2em 0;border:1px solid #C9DFF7;border-radius:10px}
table{border-collapse:collapse;width:100%;min-width:520px;font-size:.94em;background:#FFFFFF}
th,td{padding:10px 14px;text-align:left;border-bottom:1px solid #C9DFF7;vertical-align:top}
th{font-weight:700;color:#1F6FEB;background:#EFF6FF}
tr:last-child td{border-bottom:none}
.btn{display:inline-block;font-weight:700;padding:12px 26px;border-radius:10px;font-size:15px;border:2px solid #1F6FEB;transition:.18s}
.btn:hover{text-decoration:none;transform:translateY(-1px)}
.btn-p{background:#1F6FEB;color:#FFFFFF}
.btn-o{color:#1F6FEB;background:transparent}
.rg-band{background:#EFF6FF;border-top:3px solid #7FD1F5;padding:26px 0;margin-top:48px}
.rg-band p{max-width:820px;margin:0 auto;text-align:center;font-size:14.5px;color:#6f6a60}
figure.diagram{margin:1.6em 0;background:#FFFFFF;border:1px solid #C9DFF7;border-radius:10px;padding:14px}
figure.diagram figcaption{font-size:12.5px;color:#6f6a60;margin-top:8px;text-align:center}
.meta-line{display:flex;flex-wrap:wrap;gap:8px 18px;font-size:13px;color:#6f6a60;margin:14px 0 6px}
.meta-line time{font-weight:600}
.faq details{background:#FFFFFF;border:1px solid #C9DFF7;border-radius:10px;margin:10px 0;overflow:hidden}
.faq summary{cursor:pointer;font-weight:700;padding:14px 18px;list-style:none;position:relative;padding-right:44px}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"+";position:absolute;right:18px;top:50%;transform:translateY(-50%);font-size:20px;color:#7FD1F5;font-weight:700}
.faq details[open] summary::after{content:"–"}
.faq .faq-a{padding:0 18px 16px;color:#1D2B3A}
.checklist li{list-style:none;position:relative;padding-left:28px}
.checklist li::before{content:"✓";position:absolute;left:0;top:0;color:#7FD1F5;font-weight:800}
.art-body p{margin:.85em 0}
.art-body h2{font-size:1.5em;margin:1.6em 0 .5em;color:#1F6FEB}
.art-body h3{font-size:1.18em;margin:1.3em 0 .4em}
.art-body .sect{margin-bottom:1.2em}
.toc{background:#EFF6FF;border:1px solid #C9DFF7;border-radius:10px;padding:16px 18px;margin:1.4em 0}
.toc strong{display:block;margin-bottom:8px;font-size:14px;letter-spacing:.5px;text-transform:uppercase;color:#6f6a60}
.toc a{display:block;padding:3px 0;font-size:14.5px}
.crumbs{font-size:13px;color:#6f6a60;padding:14px 0}
.crumbs a{color:#6f6a60}
.crumbs span[aria-current]{color:#1D2B3A;font-weight:600}
.cardgrid{display:grid;gap:16px}
.icon-row{display:flex;gap:8px;flex-wrap:wrap;margin:10px 0}
.icon-row span{background:#EFF6FF;border:1px solid #C9DFF7;border-radius:999px;padding:3px 12px;font-size:12.5px;color:#6f6a60}
.nav-toggle{display:none}
.foot-legal{border-top:1px solid #C9DFF7;padding:18px 0;font-size:12.5px;color:#6f6a60;text-align:center}
@media (max-width:860px){
 .nav-toggle{display:block}
 nav.mainnav{display:none}
 #navopen:checked ~ nav.mainnav{display:block;position:absolute;top:100%;left:0;right:0;background:#FFFFFF;border-bottom:1px solid #C9DFF7;box-shadow:0 12px 24px rgba(0,0,0,.12)}
 nav.mainnav a{display:block;padding:13px 22px;border-top:1px solid #C9DFF7}
 .nav-label{cursor:pointer;padding:10px 14px;border:1.5px solid #C9DFF7;border-radius:10px;display:inline-flex;align-items:center;gap:8px;font-size:14px;font-weight:600}
}
@media (max-width:640px){
 body{font-size:15px}
 .cardgrid{grid-template-columns:1fr !important}
}


.topbar{background:#FFFFFF;border-bottom:1px solid #C9DFF7;position:relative}
.topbar .container{display:flex;align-items:center;justify-content:space-between;padding:13px 20px;gap:14px}
.brand{color:#1F6FEB;font-weight:800;font-size:21px}
.brand .b101{display:inline-flex;background:#1F6FEB;color:#FFFFFF;border-radius:9px;padding:2px 9px;margin-right:9px;font-size:15px;font-weight:800}
nav.mainnav a{color:#1D2B3A;font-size:14px;margin-left:17px;font-weight:600}
nav.mainnav a.on{color:#1F6FEB;background:#EFF6FF;border-radius:8px;padding:5px 11px}
.hero{background:linear-gradient(160deg,#EFF6FF 0%,#FFFFFF 70%);border-bottom:1px solid #C9DFF7}
.hero-grid{display:grid;grid-template-columns:1fr 380px;gap:40px;align-items:center;padding:52px 0}
.hero h1{font-size:37px;color:#1F6FEB;margin-bottom:13px}
.hero .lead{color:#6f6a60;font-size:16.5px;max-width:560px;margin-bottom:22px}
.kicker{display:inline-block;background:#1F6FEB;color:#FFFFFF;font-size:11.5px;font-weight:800;letter-spacing:2px;padding:4px 12px;border-radius:999px;margin-bottom:14px;text-transform:uppercase}
.hero .mapcard{background:#FFFFFF;border:1px solid #C9DFF7;border-radius:14px;padding:14px;box-shadow:0 16px 34px rgba(18,38,63,.10)}
.lessonbar{display:flex;gap:8px;flex-wrap:wrap;margin-top:18px}
.lessonbar span{font-family:Consolas, monospace;font-size:12px;background:#EFF6FF;color:#1F6FEB;border-radius:6px;padding:2px 9px;font-weight:700}
.hsection{padding:38px 0;border-bottom:1px solid #C9DFF7}
.hsection h2{font-size:24px;color:#1F6FEB;margin-bottom:4px}
.hsection .sub{color:#6f6a60;font-size:14px;margin-bottom:18px}
.lesson-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px;margin-top:20px}
.lesson{background:#FFFFFF;border:1px solid #C9DFF7;border-top:4px solid #1F6FEB;border-radius:12px;padding:18px;display:block;color:inherit}
.lesson:hover{border-color:#7FD1F5;text-decoration:none;transform:translateY(-2px)}
.lesson .ln{font-family:Consolas, monospace;font-size:12px;color:#7FD1F5;font-weight:700;letter-spacing:1px}
.lesson h3{font-size:16px;color:#1F6FEB;margin:5px 0 6px}
.lesson p{font-size:13px;color:#6f6a60}
.lesson .lbar{height:5px;background:#EFF6FF;border-radius:99px;margin-top:12px;overflow:hidden}
.lesson .lbar i{display:block;height:100%;width:100%;background:linear-gradient(90deg,#7FD1F5,#1F6FEB)}
.art-wrap{max-width:860px;margin:0 auto;padding:24px 0 40px}
.lessonbadge{display:inline-block;background:#1F6FEB;color:#FFFFFF;font-family:Consolas, monospace;font-size:12px;font-weight:800;letter-spacing:2px;padding:5px 14px;border-radius:999px;margin-bottom:12px}
.lessonnav{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin-top:34px;border-top:1px solid #C9DFF7;padding-top:22px}
.lessonnav a{background:#EFF6FF;border:1px solid #C9DFF7;border-radius:12px;padding:14px 16px;font-size:13.5px;color:#1F6FEB;font-weight:700}
.lessonnav a small{display:block;color:#6f6a60;font-weight:600;font-size:11px;letter-spacing:1.5px;text-transform:uppercase;margin-bottom:3px}
.lessonnav a.next{text-align:right}
footer.foot{background:#1F6FEB;color:#FFFFFF}
.foot-grid{display:grid;grid-template-columns:1.5fr 1fr 1fr 1fr;gap:26px;padding:38px 0 20px}
footer.foot h4{color:#7FD1F5;font-size:12.5px;letter-spacing:1.5px;text-transform:uppercase;margin-bottom:10px}
footer.foot a{color:#FFFFFF;font-size:13.5px;display:block;padding:3px 0;opacity:.92}
footer.foot p{font-size:12.8px;opacity:.85}
.foot-legal{background:#1F6FEB;border-top:1px solid rgba(255,255,255,.2)}
@media (max-width:1000px){.hero-grid{grid-template-columns:1fr}.lesson-grid{grid-template-columns:1fr 1fr}}
@media (max-width:640px){.hero h1{font-size:29px}.lesson-grid,.foot-grid,.lessonnav{grid-template-columns:1fr}}



.fl-wrap{position:fixed;left:0;right:0;bottom:0;z-index:999;display:flex;justify-content:center;padding:0 10px 10px;pointer-events:none;font-family:-apple-system, 'Segoe UI', Roboto, Arial, sans-serif}
.fl-bar{pointer-events:auto;display:flex;align-items:center;justify-content:space-between;gap:10px;width:100%;max-width:378px;background:#1F6FEB;border:2px solid #1F6FEB;border-radius:999px;padding:8px 8px 8px 16px;box-shadow:0 10px 26px rgba(0,0,0,.38);text-decoration:none}
.fl-txt{color:#FFFFFF;font-weight:800;font-size:15px;white-space:nowrap;animation:flBlink 1.6s ease-in-out infinite}
.fl-btn{position:relative;overflow:hidden;background:linear-gradient(135deg,#1F6FEB,#1F6FEB);color:#14100E;font-weight:800;font-size:14px;padding:10px 18px;border-radius:999px;white-space:nowrap;animation:flPulse 1.1s ease-in-out infinite}
.fl-btn::after{content:"";position:absolute;top:0;left:-60%;width:40%;height:100%;background:rgba(255,255,255,.45);transform:skewX(-20deg);animation:flShine 1.6s linear infinite}
@keyframes flPulse{0%,100%{transform:scale(1);box-shadow:0 0 0 0 rgba(31,111,235,.5)}50%{transform:scale(1.05);box-shadow:0 0 18px 4px rgba(31,111,235,.5)}}
@keyframes flBlink{0%,100%{opacity:1}50%{opacity:.72}}
@keyframes flShine{0%{left:-60%}100%{left:130%}}
body{padding-bottom:86px}
@media (max-width:400px){.fl-txt{font-size:13.5px}.fl-btn{padding:9px 14px;font-size:13px}}