.e5-page{--e5-green:#107c41;--e5-green-dark:#075c31;--e5-ink:#10231a;--e5-text:#33483d;--e5-soft:#f5faf7;--e5-line:#dce9e1;--e5-card:#fff;--e5-gold:#c99839;background:#fbfdfc;color:var(--e5-ink);scroll-behavior:smooth}.e5-page *{box-sizing:border-box}.e5-wrap{width:min(1180px,calc(100% - 40px));margin:auto}.e5-hero{position:relative;overflow:hidden;padding:78px 0 64px;background:radial-gradient(circle at 15% 10%,rgba(16,124,65,.16),transparent 34%),linear-gradient(135deg,#f5fbf7 0%,#fff 55%,#eef7f1 100%)}.e5-hero:before{content:"";position:absolute;width:420px;height:420px;border:1px solid rgba(16,124,65,.08);border-radius:50%;right:-120px;top:-180px;box-shadow:0 0 0 60px rgba(16,124,65,.025),0 0 0 120px rgba(16,124,65,.018)}.e5-hero-grid{display:grid;grid-template-columns:1.08fr .92fr;gap:52px;align-items:center}.e5-kicker,.e5-card-label{margin:0 0 10px;color:var(--e5-green);font-size:.78rem;font-weight:900;letter-spacing:.12em;text-transform:uppercase}.e5-hero h1{margin:.1em 0 .22em;font-size:clamp(2.8rem,6vw,5.6rem);line-height:.98;letter-spacing:-.045em}.e5-lead{max-width:720px;font-size:1.15rem;line-height:1.75;color:#42554a}.e5-tags{display:flex;gap:9px;flex-wrap:wrap;margin:22px 0}.e5-tags span{padding:7px 11px;border-radius:999px;background:rgba(255,255,255,.8);border:1px solid rgba(16,124,65,.18);box-shadow:0 6px 16px rgba(22,71,43,.05);font-size:.82rem;font-weight:800;color:#27543b}.e5-actions{display:flex;gap:12px;flex-wrap:wrap;margin:28px 0 20px}.e5-actions .btn,.e5-download-btn{border-radius:12px!important;padding:13px 19px!important;font-weight:850!important;text-decoration:none!important}.e5-primary-btn,.e5-download-btn{background:var(--e5-green)!important;color:#fff!important;border:2px solid var(--e5-green)!important;box-shadow:0 12px 28px rgba(16,124,65,.22)}.e5-secondary-btn{background:#fff!important;color:var(--e5-green-dark)!important;border:2px solid #cfe2d6!important}.e5-memory{display:inline-block;margin:0;padding:12px 15px;border-left:4px solid var(--e5-green);border-radius:8px;background:rgba(255,255,255,.72);color:#30483b}.e5-hero-media{margin:0;position:relative}.e5-hero-media img{width:100%;display:block;border-radius:24px;box-shadow:0 28px 80px rgba(9,53,30,.24);border:1px solid rgba(255,255,255,.9)}.e5-intro-band{padding:34px 0;background:#eef6f1;border-top:1px solid #e2eee6;border-bottom:1px solid #dce9e1}.e5-intro-grid{display:grid;grid-template-columns:1.15fr .85fr;gap:20px}.e5-glance-card,.e5-before-card{padding:25px;border-radius:20px;background:rgba(255,255,255,.82);border:1px solid rgba(255,255,255,.95);box-shadow:0 12px 35px rgba(28,74,47,.07);backdrop-filter:blur(16px)}.e5-glance-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:12px}.e5-glance-grid div{padding:15px;border:1px solid #e1ebe5;border-radius:14px;background:#fff}.e5-glance-grid span{display:block;margin-bottom:4px;color:#708078;font-size:.72rem;text-transform:uppercase;letter-spacing:.06em;font-weight:800}.e5-glance-grid strong{display:block;font-size:.94rem;line-height:1.35}.e5-before-card h2{margin:.15em 0 .4em;font-size:1.45rem}.e5-before-card p{margin:.55em 0;color:var(--e5-text);line-height:1.65}.e5-text-link{display:inline-block;margin-top:8px;color:var(--e5-green-dark);font-weight:800;text-decoration:none}.e5-section{padding:56px 0}.e5-watch-section{background:#fff}.e5-section-head{display:flex;gap:14px;align-items:flex-start;margin-bottom:16px}.e5-section-no{display:grid;place-items:center;flex:0 0 44px;height:44px;border-radius:13px;background:#e9f5ee;color:var(--e5-green);font-weight:950;font-size:.88rem;border:1px solid #d8eadf}.e5-section-head h2{margin:0;font-size:clamp(1.65rem,3vw,2.35rem);letter-spacing:-.02em}.e5-section-head .e5-kicker{margin-bottom:4px}.e5-section-intro,.e5-lesson-section>p{font-size:1.02rem;line-height:1.8;color:var(--e5-text)}.e5-video{position:relative;aspect-ratio:16/9;margin-top:24px;border-radius:22px;overflow:hidden;background:#111;box-shadow:0 18px 50px rgba(0,0,0,.16)}.e5-video iframe{position:absolute;inset:0;width:100%;height:100%;border:0}.e5-video-poster{position:absolute;inset:0;width:100%;height:100%;border:0;padding:0;background:#111;cursor:pointer;overflow:hidden;color:#fff}.e5-video-poster img{width:100%;height:100%;object-fit:cover;display:block}.e5-video-poster:after{content:"";position:absolute;inset:0;background:linear-gradient(180deg,transparent 42%,rgba(0,0,0,.5))}.e5-play{position:absolute;z-index:2;left:50%;top:50%;transform:translate(-50%,-50%);display:grid;place-items:center;width:72px;height:72px;border-radius:50%;background:var(--e5-green);color:#fff;font-size:1.7rem;box-shadow:0 12px 32px rgba(0,0,0,.3)}.e5-play-label{position:absolute;z-index:2;left:50%;bottom:22px;transform:translateX(-50%);font-weight:850;background:rgba(0,0,0,.7);padding:8px 14px;border-radius:999px;white-space:nowrap}.e5-video-fallback{text-align:center;font-size:.92rem;margin-top:12px;color:#5b6d62}.e5-video-fallback a{color:var(--e5-green-dark);font-weight:800}.e5-learning-shell{display:grid;grid-template-columns:260px minmax(0,1fr);gap:34px;align-items:start;padding-top:32px;padding-bottom:72px}.e5-jump{position:sticky;top:88px;max-height:calc(100vh - 110px);overflow:auto;scrollbar-width:thin}.e5-jump-card{padding:15px;border-radius:20px;background:rgba(255,255,255,.74);border:1px solid rgba(16,124,65,.13);box-shadow:0 18px 50px rgba(27,69,44,.1);backdrop-filter:blur(18px)}.e5-jump-top{display:flex;justify-content:space-between;gap:12px;align-items:center;padding:4px 5px 9px}.e5-jump-kicker{font-size:.76rem;font-weight:950;letter-spacing:.09em;text-transform:uppercase;color:#446154}.e5-jump-top strong{color:var(--e5-green);font-size:.82rem}.e5-progress-track{height:6px;border-radius:999px;background:#e6eee9;overflow:hidden;margin:0 5px 10px}.e5-progress-track span{display:block;width:0;height:100%;background:linear-gradient(90deg,var(--e5-green),#4eb675);border-radius:inherit;transition:width .2s ease}.e5-jump-links{display:grid;gap:3px}.e5-jump-links a{display:grid;grid-template-columns:28px 24px 1fr;gap:6px;align-items:center;padding:9px 8px;border-radius:11px;color:#4b5d53;text-decoration:none;transition:.18s ease}.e5-jump-links a span{font-size:.68rem;color:#839188;font-weight:850}.e5-jump-links a i{display:grid;place-items:center;width:22px;height:22px;border-radius:7px;background:#f0f5f2;color:#557164;font-style:normal;font-size:.72rem;font-weight:900}.e5-jump-links a b{font-size:.78rem;line-height:1.2;font-weight:780}.e5-jump-links a:hover{background:#f0f7f3;color:#173626}.e5-jump-links a.is-active{background:#e7f4ec;color:#0b5d31;box-shadow:inset 3px 0 0 var(--e5-green)}.e5-jump-links a.is-active i{background:var(--e5-green);color:#fff}.e5-mobile-jump{display:none}.e5-lesson{min-width:0}.e5-lesson-section{scroll-margin-top:100px;padding:48px 0;border-bottom:1px solid #e7eeea}.e5-lesson-section:first-child{padding-top:24px}.e5-logic-card,.e5-key-card,.e5-think-card,.e5-definition-card,.e5-plain-card,.e5-brackets-card,.e5-test-card{margin:22px 0;border-radius:18px;padding:21px;background:#fff;border:1px solid var(--e5-line);box-shadow:0 10px 30px rgba(30,72,48,.055)}.e5-logic-question{font-weight:900;color:#183526}.e5-logic-answers{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-top:14px}.e5-logic-answers span{padding:12px;border-radius:12px;background:#f5faf7;color:#315040}.e5-logic-answers b{color:var(--e5-green-dark)}.e5-key-card,.e5-definition-card{border-left:4px solid var(--e5-green);background:#f4faf6}.e5-key-card span,.e5-think-card span,.e5-plain-card span,.e5-try-card>span,.e5-connected-card>span{display:inline-block;margin-bottom:7px;color:var(--e5-green);font-size:.74rem;font-weight:950;letter-spacing:.09em;text-transform:uppercase}.e5-key-card p,.e5-think-card p,.e5-definition-card p,.e5-plain-card p{margin:0;line-height:1.7;color:#31483c}.e5-think-card{background:#fff9eb;border-color:#ecdba8}.e5-think-card span{color:#8a6414}.e5-compare-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:14px;margin:22px 0}.e5-compare-grid article{padding:19px;border:1px solid var(--e5-line);border-radius:17px;background:#fff}.e5-compare-grid article>span{font-size:.72rem;color:#718078;font-weight:900;text-transform:uppercase;letter-spacing:.08em}.e5-compare-grid h3{margin:.35em 0 .2em;font-size:1.12rem}.e5-compare-grid p{margin:0;color:#6a796f}.e5-simple-vs-nested{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin:20px 0}.e5-simple-vs-nested div{padding:20px;border-radius:17px;background:#fff;border:1px solid var(--e5-line)}.e5-simple-vs-nested div:last-child{background:linear-gradient(135deg,#eaf6ee,#f8fcfa);border-color:#cfe5d7}.e5-simple-vs-nested span{display:block;margin-bottom:7px;color:#728179;font-size:.72rem;font-weight:900;text-transform:uppercase}.e5-simple-vs-nested strong{font-size:1.05rem}.e5-decision-flow{display:grid;gap:10px;margin:24px 0}.e5-decision-flow>div{display:grid;grid-template-columns:78px 1fr auto;align-items:center;gap:14px;padding:16px 18px;border-radius:14px;background:#fff;border:1px solid var(--e5-line)}.e5-decision-flow b{color:#64766b}.e5-decision-flow span{font-weight:850}.e5-decision-flow em{font-style:normal;color:#7a897f}.e5-decision-flow .is-true{border-color:#98cfad;background:#eff9f3}.e5-decision-flow .is-true b,.e5-decision-flow .is-true em{color:var(--e5-green-dark)}.e5-decision-flow .is-stop{background:#14291d;color:#fff;border-color:#14291d}.e5-decision-flow .is-stop b,.e5-decision-flow .is-stop em{color:#9fd8b5}.e5-memory-line{margin:24px 0;padding:14px 17px;border-radius:12px;background:#163123;color:#fff;font-weight:900;text-align:center;letter-spacing:.01em}.e5-rule-table{display:grid;grid-template-columns:repeat(5,1fr);gap:8px;margin:20px 0}.e5-rule-table div{padding:14px 10px;text-align:center;border-radius:13px;background:#fff;border:1px solid var(--e5-line)}.e5-rule-table b,.e5-rule-table span{display:block}.e5-rule-table b{font-size:.86rem;color:#6c7c73}.e5-rule-table span{margin-top:3px;font-weight:900;color:#163727}.e5-build-steps{display:grid;gap:12px;margin:24px 0}.e5-build-steps article{display:grid;grid-template-columns:42px 1fr;gap:14px;align-items:start;padding:18px;border-radius:17px;background:#fff;border:1px solid var(--e5-line)}.e5-build-steps article>span{display:grid;place-items:center;width:38px;height:38px;border-radius:12px;background:#e9f5ee;color:var(--e5-green);font-weight:950}.e5-build-steps h3{margin:0 0 8px;font-size:1rem}.e5-build-steps code,.e5-system-formulas code{display:block;padding:10px 12px;border-radius:9px;background:#14271d;color:#d8f4e3;font:700 .9rem/1.55 Consolas,Monaco,monospace;overflow:auto}.e5-build-steps p{margin:8px 0 0;color:#697970;line-height:1.55}.e5-formula-card{margin:22px 0;border-radius:17px;overflow:hidden;background:#12261b;box-shadow:0 13px 36px rgba(13,46,28,.14)}.e5-formula-card--hero{border:1px solid rgba(70,176,111,.4)}.e5-formula-top{display:flex;justify-content:space-between;align-items:center;gap:12px;padding:10px 12px 0 16px;color:#a8c9b5}.e5-formula-top span{font-size:.74rem;font-weight:850;letter-spacing:.06em;text-transform:uppercase}.e5-copy{border:1px solid #416a50;background:#1d3b29;color:#e3f7ea;border-radius:9px;padding:7px 10px;font-size:.72rem;font-weight:850;cursor:pointer}.e5-copy:hover{background:#275237}.e5-copy.is-copied{background:#2d7548;border-color:#2d7548}.e5-formula-card code{display:block;padding:16px;overflow:auto;color:#f4fff7;font:750 .94rem/1.65 Consolas,Monaco,monospace;white-space:nowrap}.e5-plain-card{background:#eef7f1;border-color:#d1e5d8}.e5-brackets-card{display:grid;grid-template-columns:1fr 1fr;gap:12px;background:#fff}.e5-brackets-card div{padding:13px;border-radius:12px;background:#f6faf8}.e5-brackets-card div span{display:block;color:var(--e5-green);font:900 1.3rem Consolas,monospace}.e5-brackets-card div strong{font-size:.88rem}.e5-brackets-card p{grid-column:1/-1;margin:0;color:#42554a;line-height:1.65}.e5-wrong-right{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin:22px 0}.e5-wrong-right article{padding:20px;border-radius:17px;border:1px solid}.e5-wrong-right article>span{font-size:.72rem;font-weight:950;text-transform:uppercase;letter-spacing:.08em}.e5-wrong-right code{display:block;margin:10px 0;padding:10px;border-radius:9px;background:#15231b;color:#fff;overflow:auto}.e5-wrong-right p{margin:0;line-height:1.65}.e5-wrong-right .is-wrong{background:#fff5f3;border-color:#efc7bd}.e5-wrong-right .is-wrong>span{color:#a6412a}.e5-wrong-right .is-right{background:#f0f9f3;border-color:#c6e3d0}.e5-wrong-right .is-right>span{color:var(--e5-green)}.e5-note-light{padding:13px 15px;border-radius:12px;background:#f6f8f7;color:#58695f!important}.e5-system-section{position:relative}.e5-system-head{display:flex;gap:16px;align-items:center;padding:22px;border-radius:20px;background:linear-gradient(135deg,#f1f8f4,#fff);border:1px solid #dce9e1;margin-bottom:22px}.e5-system-icon{display:grid;place-items:center;flex:0 0 62px;width:62px;height:62px;border-radius:18px;background:var(--e5-green);color:#fff;font-size:1.6rem;font-weight:950;box-shadow:0 12px 26px rgba(16,124,65,.22)}.e5-system-head span{color:var(--e5-green);font-size:.72rem;font-weight:950;text-transform:uppercase;letter-spacing:.09em}.e5-system-head h2{margin:.15em 0 .2em;font-size:clamp(1.7rem,3vw,2.3rem)}.e5-system-head p{margin:0;color:#617168}.stock-system .e5-system-icon{background:#496d56}.payment-system .e5-system-icon{background:#8c6b28}.student-system .e5-system-icon{background:#234b36}.e5-boundaries{display:flex;gap:8px;flex-wrap:wrap;margin:16px 0}.e5-boundaries span{padding:9px 11px;border-radius:999px;background:#f0f5f2;border:1px solid #e0e9e3;font-size:.82rem;font-weight:800;color:#4d6256}.e5-try-card{margin:22px 0;padding:20px;border-radius:18px;background:#fffaf0;border:1px solid #ead9a6}.e5-try-card>span{color:#8a6414}.e5-try-card h3{margin:.25em 0 .7em;font-size:1.04rem}.e5-reveal{border:0;border-radius:10px;background:#203c2b;color:#fff;padding:10px 13px;font-weight:850;cursor:pointer}.e5-reveal:hover{background:#10291b}.e5-answer{margin-top:13px;padding:13px 15px;border-radius:12px;background:#fff;border:1px solid #eadfc1}.e5-answer p{margin:.35em 0 0;line-height:1.6;color:#5c685f}.e5-connection-flow,.e5-assignment-flow{display:flex;align-items:center;gap:9px;flex-wrap:wrap;margin:20px 0}.e5-connection-flow span,.e5-assignment-flow span{padding:10px 12px;border-radius:10px;background:#edf5f0;border:1px solid #d9e6de;font-weight:850;color:#31523f}.e5-connection-flow i,.e5-assignment-flow i{font-style:normal;color:#91a198}.e5-system-formulas{display:grid;grid-template-columns:repeat(2,1fr);gap:12px;margin:22px 0}.e5-system-formulas article{padding:17px;border-radius:16px;background:#fff;border:1px solid var(--e5-line)}.e5-system-formulas article>span{display:block;margin-bottom:8px;color:#64776c;font-size:.75rem;font-weight:900;text-transform:uppercase}.e5-system-formulas article p{margin:.7em 0 0;line-height:1.55;color:#68786f}.e5-system-formulas .is-focus{grid-column:1/-1;border-color:#b9d9c5;background:#f3faf5}.e5-connected-card{padding:22px;border-radius:20px;background:#f6faf8;border:1px solid var(--e5-line);margin-top:20px}.e5-connected-card>p{color:#4d6256;line-height:1.7}.e5-test-card{border-left:4px solid var(--e5-green);background:#eef7f1}.e5-test-card p{margin:.4em 0 0;color:#42584b;line-height:1.7}.e5-mistake-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:12px;margin:22px 0}.e5-mistake-grid article{padding:18px;border-radius:16px;background:#fff;border:1px solid var(--e5-line)}.e5-mistake-grid b{display:grid;place-items:center;width:30px;height:30px;border-radius:9px;background:#edf5f0;color:var(--e5-green);font-size:.74rem}.e5-mistake-grid h3{margin:.7em 0 .3em;font-size:1rem}.e5-mistake-grid p{margin:0;line-height:1.6;color:#68786f}.e5-practice-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:12px}.e5-practice-grid .e5-try-card{margin:0}.e5-recap-card{padding:28px;border-radius:22px;background:linear-gradient(135deg,#10271a,#1c422d);color:#fff;box-shadow:0 18px 50px rgba(12,46,27,.18)}.e5-recap-card .e5-kicker{color:#8ee1ad}.e5-recap-card .e5-section-no{background:#2c5c3d;border-color:#3d7150;color:#c7f2d6}.e5-recap-card ul{margin:20px 0;padding-left:22px;display:grid;gap:10px}.e5-recap-card li{line-height:1.55;color:#e7f3eb}.e5-recap-close{margin:20px 0 0;padding-top:18px;border-top:1px solid rgba(255,255,255,.16);font-size:1.15rem;font-weight:900;color:#a9e1bd}.e5-assignment-section{padding:34px;border-radius:24px;background:#f1f8f4;border:1px solid #d6e8dc;margin-top:34px}.e5-assignment-section .e5-section-head{margin-top:0}.e5-assignment-note{margin-top:18px;padding:15px;border-radius:13px;background:#fff;color:#43574b;line-height:1.65}.e5-next-section{border-bottom:0}.e5-next-questions{display:grid;grid-template-columns:repeat(2,1fr);gap:10px;margin:20px 0}.e5-next-questions span{padding:14px;border-radius:13px;background:#fff;border:1px solid var(--e5-line);font-weight:800;color:#3c5546}.e5-journey{display:grid;grid-template-columns:repeat(5,1fr);gap:8px;margin:26px 0 0}.e5-journey a,.e5-journey strong{padding:13px 10px;border-radius:11px;background:#fff;border:1px solid var(--e5-line);text-align:center;text-decoration:none;color:#284b37;font-size:.82rem}.e5-journey strong{background:var(--e5-green);color:#fff;border-color:var(--e5-green)}
@media(max-width:980px){.e5-hero-grid,.e5-intro-grid{grid-template-columns:1fr}.e5-learning-shell{display:block}.e5-jump{display:none}.e5-mobile-jump{display:block;position:sticky;top:66px;z-index:12;margin:0 0 8px;padding-top:8px}.e5-mobile-jump>button{width:100%;display:flex;justify-content:space-between;gap:12px;align-items:center;padding:12px 14px;border-radius:13px;border:1px solid #cfe2d6;background:rgba(255,255,255,.94);backdrop-filter:blur(14px);box-shadow:0 8px 24px rgba(18,67,39,.1);font-weight:850;color:#1d3d2b}.e5-mobile-jump>button strong{color:var(--e5-green)}#e5MobileJumpMenu{margin-top:6px;padding:9px;border-radius:15px;background:rgba(255,255,255,.97);border:1px solid #dbe8df;box-shadow:0 16px 35px rgba(18,57,35,.14);max-height:60vh;overflow:auto}#e5MobileJumpMenu a{display:flex;gap:9px;padding:10px;border-radius:10px;text-decoration:none;color:#3c5546;font-size:.86rem}#e5MobileJumpMenu a:hover,#e5MobileJumpMenu a.is-active{background:#eef7f1;color:var(--e5-green-dark)}.e5-practice-grid{grid-template-columns:1fr}.e5-lesson-section:first-child{padding-top:32px}}
@media(max-width:720px){.e5-wrap{width:min(100% - 26px,1180px)}.e5-hero{padding:48px 0 40px}.e5-hero h1{font-size:clamp(2.45rem,12vw,4rem)}.e5-lead{font-size:1.02rem}.e5-glance-grid{grid-template-columns:1fr 1fr}.e5-actions{flex-direction:column}.e5-actions .btn{width:100%;text-align:center}.e5-section{padding:42px 0}.e5-lesson-section{padding:38px 0}.e5-section-head{gap:10px}.e5-section-no{flex-basis:38px;height:38px;border-radius:11px}.e5-compare-grid,.e5-simple-vs-nested,.e5-wrong-right,.e5-system-formulas,.e5-mistake-grid,.e5-next-questions{grid-template-columns:1fr}.e5-system-formulas .is-focus{grid-column:auto}.e5-rule-table{grid-template-columns:repeat(2,1fr)}.e5-decision-flow>div{grid-template-columns:60px 1fr}.e5-decision-flow em{grid-column:2}.e5-brackets-card{grid-template-columns:1fr}.e5-brackets-card p{grid-column:auto}.e5-system-head{align-items:flex-start}.e5-connection-flow,.e5-assignment-flow{align-items:flex-start}.e5-assignment-flow i{display:none}.e5-assignment-section{padding:24px 18px}.e5-journey{grid-template-columns:1fr}.e5-play{width:60px;height:60px;font-size:1.4rem}.e5-play-label{font-size:.82rem}}
@media(max-width:430px){.e5-glance-grid{grid-template-columns:1fr}.e5-rule-table{grid-template-columns:1fr 1fr}.e5-system-head{padding:18px}.e5-system-icon{flex-basis:52px;width:52px;height:52px}.e5-formula-card code{font-size:.84rem}.e5-copy{padding:6px 8px}.e5-formula-top{align-items:flex-start}}
#overview,#before-you-begin,#watch{scroll-margin-top:100px}