:root{--bg:#f4f7f5;--surface:#fff;--surface-2:#edf3f0;--ink:#15251f;--muted:#607068;--line:#dce5e0;--brand:#176b55;--brand-dark:#0f4f3f;--accent:#f0b45d;--danger:#b94736;--shadow:0 18px 48px rgba(24,55,45,.10);--radius:24px}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--bg);color:var(--ink);font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;line-height:1.65}button,input,textarea{font:inherit}button{touch-action:manipulation}a{color:inherit}.shell{width:min(1120px,calc(100% - 32px));margin-inline:auto}.narrow{max-width:780px}.skip-link{position:absolute;left:-9999px;top:auto}.skip-link:focus{left:16px;top:16px;z-index:999;background:#fff;padding:10px 14px;border-radius:10px}
.site-header{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.92);border-bottom:1px solid rgba(220,229,224,.9);backdrop-filter:blur(14px)}.header-row{min-height:74px;display:flex;align-items:center;justify-content:space-between;gap:24px}.brand{display:flex;align-items:center;gap:11px;text-decoration:none}.brand img,.brand-mark{width:40px;height:40px;border-radius:12px}.brand-mark{display:grid;place-items:center;background:var(--brand);color:#fff;font-size:1.35rem;font-weight:900}.brand strong,.brand small{display:block}.brand strong{font-size:1rem}.brand small{font-size:.76rem;color:var(--muted)}.site-nav{display:flex;align-items:center;gap:22px}.site-nav a{text-decoration:none;font-weight:700;font-size:.92rem;color:#34463e}.site-nav a:hover{color:var(--brand)}.nav-action,.button.primary{background:var(--brand)!important;color:#fff!important}.nav-action{padding:10px 15px;border-radius:999px}.site-nav-toggle{display:none;border:0;background:transparent;padding:8px}.site-nav-toggle span{display:block;width:23px;height:2px;margin:5px;background:var(--ink)}
.hero{padding:58px 0 26px;background:linear-gradient(180deg,#fff 0%,var(--bg) 100%)}.hero-inner{text-align:center;max-width:780px}.kicker,.eyebrow{margin:0 0 8px;color:var(--brand);font-size:.78rem;font-weight:850;letter-spacing:.12em;text-transform:uppercase}.hero h1{margin:0;font-size:clamp(2.7rem,7vw,5.2rem);line-height:1.02;letter-spacing:-.055em}.hero-lead{max-width:680px;margin:18px auto 0;color:var(--muted);font-size:clamp(1rem,2.2vw,1.2rem)}.hero-points{display:flex;justify-content:center;flex-wrap:wrap;gap:10px 22px;padding:0;margin:22px 0 0;list-style:none;color:#3f5149;font-weight:700;font-size:.9rem}.hero-points li:before{content:"✓";margin-right:7px;color:var(--brand)}
.calculator-section{padding:28px 0 62px}.calculator-card{background:var(--surface);border:1px solid var(--line);border-radius:30px;padding:26px;box-shadow:var(--shadow)}.calculator-card__header{display:flex;align-items:flex-end;justify-content:space-between;gap:28px;margin-bottom:26px}.calculator-card__intro{max-width:630px}.calculator-card__intro h2{margin:0 0 7px;font-size:clamp(1.6rem,3vw,2.25rem);letter-spacing:-.035em}.calculator-card__intro p{margin:0;color:var(--muted)}.calculator-mode-switch{display:grid;grid-template-columns:1fr 1fr;min-width:390px;padding:5px;background:var(--surface-2);border-radius:999px}.calculator-mode-tab{min-height:48px;border:0;border-radius:999px;background:transparent;color:var(--muted);font-weight:800;padding:9px 17px;cursor:pointer}.calculator-mode-tab.is-active{background:#fff;color:var(--ink);box-shadow:0 5px 18px rgba(20,47,39,.09)}.calculator-view{display:none;width:100%}.calculator-view.is-active{display:block}.calculator-stage{display:grid;place-items:center}.calculator-device{margin-inline:auto;background:#20362f;border-radius:27px;padding:18px;box-shadow:0 18px 42px rgba(12,34,27,.2)}.calculator-device--basic{width:min(430px,100%)}.calculator-device--scientific{width:min(940px,100%)}.calculator-display{min-height:126px;margin-bottom:14px;padding:15px 17px;border-radius:17px;background:#e3ece0;color:#10241d;display:flex;flex-direction:column;justify-content:flex-end}.calculator-display__expression{min-height:26px;text-align:right;color:#617068;font-size:.92rem}.calculator-display__result{width:100%;border:0;background:transparent;color:#10241d;text-align:right;font-size:clamp(2rem,6vw,3rem);font-weight:750;outline:0}.basic-keypad,.scientific-keypad{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:9px}.calculator-key,.scientific-functions button,.science-control,.angle-switch button,.science-history-button{border:0;border-radius:13px;cursor:pointer;font-weight:800}.calculator-key{min-height:57px;background:#f7f4ec;color:#183229;font-size:1.05rem;box-shadow:inset 0 -2px 0 rgba(0,0,0,.10)}.calculator-key:active,.scientific-functions button:active{transform:translateY(1px)}.calculator-key--utility{background:#dfe7e3}.calculator-key--operator{background:#d7ebe4;color:var(--brand-dark)}.calculator-key--danger{background:#f4dcd7;color:#7c3024}.calculator-key--equals{background:var(--accent);color:#342006}.calculator-key--zero{grid-column:span 2}.calculator-help{text-align:center;margin:13px 0 0;color:var(--muted);font-size:.86rem}

/* =========================================================
   SCIENTIFIC CALCULATOR — COMPLETE LAYOUT
   ========================================================= */

.scientific-topbar{
    display:flex;
    align-items:center;
    justify-content:space-between;
    gap:12px;
    margin-bottom:12px
}

.angle-switch{
    display:inline-flex;
    flex:0 0 auto;
    padding:4px;
    border-radius:999px;
    background:rgba(255,255,255,.09)
}

.angle-switch button,
.science-history-button{
    min-height:40px;
    border:0;
    border-radius:999px;
    padding:8px 14px;
    background:transparent;
    color:#dce8e3;
    cursor:pointer;
    font-weight:800
}

.angle-switch button.is-active{
    background:#fff;
    color:var(--ink);
    box-shadow:0 4px 14px rgba(0,0,0,.12)
}

.science-history-button{
    border:1px solid rgba(255,255,255,.16);
    border-radius:13px
}

.science-history-button:hover,
.angle-switch button:not(.is-active):hover{
    background:rgba(255,255,255,.08)
}

.calculator-display--scientific{
    min-height:146px;
    padding:18px 19px
}

.scientific-expression{
    width:100%;
    min-height:34px;
    border:0;
    background:transparent;
    outline:0;
    color:#284039;
    font-size:1.05rem;
    line-height:1.45
}

.scientific-expression::placeholder{
    color:#718078;
    opacity:1
}

.scientific-result{
    display:block;
    width:100%;
    overflow:hidden;
    text-align:right;
    text-overflow:ellipsis;
    white-space:nowrap;
    font-size:clamp(2rem,4vw,2.65rem);
    font-weight:850;
    line-height:1.2
}

.scientific-status{
    margin-top:4px;
    text-align:right;
    color:#65756d;
    font-size:.8rem
}

.science-history{
    margin:0 0 14px;
    padding:12px;
    border:1px solid rgba(255,255,255,.09);
    border-radius:15px;
    background:rgba(255,255,255,.07);
    color:#fff
}

.science-history-head{
    display:flex;
    align-items:center;
    justify-content:space-between;
    gap:16px
}

.science-history-head button{
    border:0;
    background:transparent;
    color:#f5d7cf;
    cursor:pointer;
    font-weight:750
}

.science-history-list{
    max-height:190px;
    overflow:auto;
    margin-top:8px;
    scrollbar-width:thin
}

.science-history-item{
    width:100%;
    display:flex;
    align-items:center;
    justify-content:space-between;
    gap:16px;
    padding:10px 8px;
    border:0;
    border-top:1px solid rgba(255,255,255,.10);
    background:transparent;
    color:#fff;
    text-align:left;
    cursor:pointer
}

.science-history-item:hover{
    background:rgba(255,255,255,.06)
}

.science-empty{
    margin:8px 0 0;
    color:#cbd8d2
}

/*
 Desktop:
 ┌──────────────────────────┬──────────────┐
 │ Scientific functions     │ Numeric pad  │
 │ Actions                  │              │
 └──────────────────────────┴──────────────┘
*/
.scientific-layout{
    display:grid;
    grid-template-columns:minmax(0,1fr) minmax(300px,340px);
    grid-template-areas:
        "functions keypad"
        "actions   keypad";
    gap:14px 16px;
    align-items:start
}

.scientific-functions{
    grid-area:functions;
    display:grid;
    gap:12px;
    min-width:0
}

.science-function-group{
    min-width:0;
    padding:12px;
    border:1px solid rgba(255,255,255,.04);
    border-radius:16px;
    background:rgba(255,255,255,.07)
}

.science-function-group h3{
    margin:0 0 9px;
    color:#d8e5df;
    font-size:.72rem;
    font-weight:800;
    letter-spacing:.075em;
    line-height:1.25;
    text-transform:uppercase
}

.science-function-grid{
    display:grid;
    grid-template-columns:repeat(6,minmax(0,1fr));
    gap:7px
}

.scientific-functions button{
    min-width:0;
    min-height:49px;
    border:0;
    border-radius:13px;
    padding:8px 5px;
    background:#f5f2e9;
    color:#17342b;
    cursor:pointer;
    font-size:.96rem;
    font-weight:850;
    line-height:1;
    box-shadow:inset 0 -2px 0 rgba(0,0,0,.09)
}

.scientific-functions button:hover{
    filter:brightness(.975)
}

.scientific-functions button:active{
    transform:translateY(1px)
}

.scientific-actions{
    grid-area:actions;
    display:grid;
    grid-template-columns:repeat(2,minmax(0,1fr));
    gap:9px;
    min-width:0
}

.science-control{
    min-height:44px;
    border:1px solid rgba(255,255,255,.05);
    border-radius:13px;
    padding:8px 12px;
    background:rgba(255,255,255,.12);
    color:#fff;
    cursor:pointer;
    font-weight:850
}

.science-control:hover{
    background:rgba(255,255,255,.17)
}

.scientific-keypad{
    grid-area:keypad;
    display:grid;
    grid-template-columns:repeat(4,minmax(0,1fr));
    gap:9px;
    width:100%;
    min-width:0;
    align-self:start
}

.scientific-keypad .calculator-key{
    min-height:57px
}

.calculator-key:focus-visible,
.scientific-functions button:focus-visible,
.science-control:focus-visible,
.angle-switch button:focus-visible,
.science-history-button:focus-visible,
.calculator-mode-tab:focus-visible{
    outline:3px solid rgba(240,180,93,.58);
    outline-offset:2px
}

.quick-section,.content-section,.faq-section,.page-section{padding:62px 0}.section-heading{max-width:720px;margin-bottom:24px}.section-heading.compact{margin-bottom:20px}.section-heading h2{margin:0 0 8px;font-size:clamp(1.7rem,3.5vw,2.5rem);letter-spacing:-.035em}.section-heading p{margin:0;color:var(--muted)}.quick-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:14px}.quick-grid article{background:#fff;border:1px solid var(--line);border-radius:20px;padding:20px}.quick-grid article>span{display:grid;place-items:center;width:42px;height:42px;margin-bottom:14px;border-radius:12px;background:#e7f1ed;color:var(--brand);font-weight:900}.quick-grid h3{margin:0 0 6px;font-size:1rem}.quick-grid p{margin:0;color:var(--muted);font-size:.92rem}.content-section{background:#fff}.content-grid,.document-layout{display:grid;grid-template-columns:minmax(0,1fr) 280px;gap:42px;align-items:start}.prose{font-size:1rem}.prose h2{scroll-margin-top:95px;margin:2.1em 0 .55em;font-size:clamp(1.45rem,3vw,2rem);line-height:1.2;letter-spacing:-.025em}.prose h2:first-child{margin-top:0}.prose h3{margin:1.6em 0 .45em}.prose p,.prose ul,.prose ol{margin:0 0 1em}.prose ul,.prose ol{padding-left:1.25em}.prose strong{color:#193a30}.prose .seo-note{padding:16px 18px;border-left:4px solid var(--brand);border-radius:0 14px 14px 0;background:#eef5f2}.toc,.side-faq{position:sticky;top:96px;background:var(--bg);border:1px solid var(--line);border-radius:18px;padding:18px}.toc strong,.toc a{display:block}.toc a{padding:7px 0;color:var(--brand);text-decoration:none}.toc p{font-size:.84rem;color:var(--muted)}.faq-shell{max-width:880px}.faq-list{display:grid;gap:10px}.faq-list details,.side-faq details{background:#fff;border:1px solid var(--line);border-radius:16px;padding:0 18px}.faq-list summary,.side-faq summary{display:flex;justify-content:space-between;gap:20px;padding:17px 0;cursor:pointer;font-weight:800;list-style:none}.faq-list summary::-webkit-details-marker{display:none}.faq-list details p{margin:0;padding:0 0 17px;color:var(--muted)}.faq-list details[open] summary span{transform:rotate(45deg)}
.page-hero{padding:54px 0 34px;background:#fff;border-bottom:1px solid var(--line)}.page-hero h1{font-size:clamp(2.2rem,5vw,3.8rem);letter-spacing:-.045em;margin:8px 0 12px}.page-intro{color:var(--muted);font-size:1.08rem}.breadcrumbs{display:flex;gap:8px;color:var(--muted);font-size:.86rem}.breadcrumbs a{color:var(--brand)}.document{background:#fff;border:1px solid var(--line);border-radius:22px;padding:30px}.contact-form{display:grid;gap:16px;margin-top:24px}.form-row{display:grid;grid-template-columns:1fr 1fr;gap:14px}.contact-form label{display:grid;gap:6px;font-weight:700}.contact-form input,.contact-form textarea{width:100%;border:1px solid var(--line);border-radius:12px;background:#fff;padding:11px 12px}.button{display:inline-flex;align-items:center;justify-content:center;border:0;border-radius:999px;padding:11px 18px;text-decoration:none;font-weight:800;cursor:pointer}.alert{padding:13px 15px;border-radius:12px}.alert.success{background:#e7f4ec}.alert.error{background:#f8e6e2}.hp-field{position:absolute;left:-9999px}
.site-footer{padding:42px 0;background:#16342b;color:#d8e4df}.footer-grid{display:grid;grid-template-columns:1.2fr 1fr;gap:28px}.footer-name{color:#fff;font-size:1.1rem}.site-footer p{max-width:520px;margin:.5em 0;color:#bcd0c7}.site-footer nav{display:flex;justify-content:flex-end;align-content:flex-start;flex-wrap:wrap;gap:10px 18px}.site-footer a{text-decoration:none}.footer-note{grid-column:1/-1;display:flex;justify-content:space-between;gap:20px;padding-top:22px;border-top:1px solid rgba(255,255,255,.13);font-size:.8rem;color:#abc0b7}
@media(max-width:900px){.site-nav-toggle{display:block}.site-nav{position:absolute;top:74px;left:16px;right:16px;display:none;flex-direction:column;align-items:stretch;background:#fff;border:1px solid var(--line);border-radius:17px;padding:16px;box-shadow:var(--shadow)}.site-nav.is-open{display:flex}.calculator-card__header{align-items:stretch;flex-direction:column}.calculator-mode-switch{min-width:0;width:100%}.scientific-layout{
grid-template-columns:minmax(0,1fr) minmax(280px,320px);
grid-template-areas:
"functions keypad"
"actions keypad"
}
.science-function-grid{grid-template-columns:repeat(3,minmax(0,1fr))}.quick-grid{grid-template-columns:repeat(2,1fr)}.content-grid,.document-layout{grid-template-columns:1fr}.toc,.side-faq{position:static}.footer-grid{grid-template-columns:1fr}.site-footer nav{justify-content:flex-start}.footer-note{grid-column:auto}}

@media(max-width:760px){
.scientific-layout{
    grid-template-columns:1fr;
    grid-template-areas:
        "functions"
        "actions"
        "keypad";
    gap:12px
}
.scientific-keypad{
    width:min(100%,480px);
    margin-inline:auto
}
.scientific-actions{
    width:min(100%,480px);
    margin-inline:auto
}
.science-function-grid{
    grid-template-columns:repeat(3,minmax(0,1fr))
}
}

@media(max-width:600px){.shell{width:min(100% - 20px,1120px)}.brand small{display:none}.hero{padding-top:42px}.hero h1{font-size:2.75rem}.calculator-card{padding:14px 10px;border-radius:22px}.calculator-mode-tab{padding:8px;font-size:.8rem}.calculator-device{padding:11px;border-radius:20px}.calculator-key{min-height:50px}.scientific-topbar{align-items:center}
.science-history-button{font-size:.8rem}
.science-function-grid{gap:6px}
.scientific-functions button{min-height:46px;font-size:.9rem}
.scientific-keypad{gap:7px}
.scientific-keypad .calculator-key{min-height:51px}
.science-function-group{padding:10px}
.calculator-display--scientific{min-height:132px;padding:15px}.quick-grid{grid-template-columns:1fr}.content-section,.quick-section,.faq-section,.page-section{padding:46px 0}.document{padding:20px}.form-row{grid-template-columns:1fr}.footer-note{flex-direction:column}.footer-grid{gap:18px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{animation:none!important;transition:none!important}}