/* Math Worksheet Hub — v2 design system, matching live site (blue/white SaaS look) */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800;900&display=swap');

:root{
  --blue:#2563EB;
  --blue-dark:#1D4ED8;
  --blue-50:#EFF4FF;
  --ink:#0F172A;
  --ink-soft:#475569;
  --muted:#64748B;
  --border:#E2E8F0;
  --bg-alt:#F8FAFC;
  --navy:#0B1220;
  --amber:#FBBF24;
  --green:#16A34A;
  --radius:16px;
  --shadow:0 1px 2px rgba(15,23,42,.04), 0 8px 24px rgba(15,23,42,.06);
  --max:1180px;
}
*{box-sizing:border-box;}
html{scroll-behavior:smooth;}
body{
  margin:0; background:#fff; color:var(--ink);
  font-family:'Inter',system-ui,sans-serif; line-height:1.6; -webkit-font-smoothing:antialiased;
}
@media (prefers-reduced-motion: reduce){ *{animation:none !important; transition:none !important;} }
h1,h2,h3,h4{font-family:'Inter',sans-serif; font-weight:800; margin:0 0 .5em; letter-spacing:-.02em; color:var(--ink);}
h1{font-size:clamp(2.2rem,4.8vw,3.6rem); line-height:1.08;}
h2{font-size:clamp(1.6rem,3vw,2.2rem);}
h3{font-size:1.15rem; font-weight:700;}
p{margin:0 0 1em; color:var(--ink-soft);}
a{color:var(--blue); text-decoration:none;}
a:hover{text-decoration:underline;}
a:focus-visible, button:focus-visible, input:focus-visible, select:focus-visible, textarea:focus-visible{
  outline:3px solid var(--amber); outline-offset:2px;
}
.wrap{max-width:var(--max); margin:0 auto; padding:0 24px;}

/* Announcement bar */
.announce{background:var(--blue); color:#fff; padding:12px 0; font-size:.9rem;}
.announce .wrap{display:flex; align-items:center; justify-content:center; gap:16px; position:relative;}
.announce .fb-btn{background:#fff; color:var(--blue); font-weight:700; padding:7px 16px; border-radius:100px; font-size:.85rem;}
.announce .fb-btn:hover{text-decoration:none; opacity:.92;}
.announce .close{position:absolute; right:0; background:none; border:none; color:#fff; font-size:1.1rem; cursor:pointer; opacity:.85; padding:4px;}
.announce.hidden{display:none;}

/* Header */
header.site{border-bottom:1px solid var(--border); background:#fff; position:sticky; top:0; z-index:30;}
.nav{display:flex; align-items:center; justify-content:space-between; padding:16px 0;}
.brand{display:flex; align-items:center; gap:12px; font-weight:800; font-size:1.2rem; color:var(--ink);}
.brand:hover{text-decoration:none;}
.brand .mark{
  width:44px;height:44px; border-radius:50%; border:2px solid var(--navy);
  display:flex; align-items:center; justify-content:center; background:#fff; flex-shrink:0;
}
.brand .mark svg{width:24px;height:24px;}
nav.links{display:flex; gap:8px; align-items:center;}
nav.links a{
  display:flex; align-items:center; gap:7px; color:var(--ink-soft); font-weight:600; font-size:.92rem;
  padding:9px 14px; border-radius:10px;
}
nav.links a:hover{background:var(--bg-alt); text-decoration:none;}
nav.links a.active{color:var(--blue); background:var(--blue-50);}
nav.links a svg{width:17px;height:17px; flex-shrink:0;}

/* Hero */
.hero{padding:72px 0 48px; text-align:center;}
.hero h1{max-width:900px; margin:0 auto .3em;}
.hero h1 .blue{color:var(--blue); display:block;}
.hero .lede{font-size:1.15rem; max-width:680px; margin:0 auto 30px;}
.hero-actions{display:flex; gap:14px; justify-content:center; flex-wrap:wrap;}

.btn{
  display:inline-flex; align-items:center; gap:8px; padding:13px 24px; border-radius:12px;
  font-weight:700; font-size:.95rem; cursor:pointer; border:2px solid var(--blue); background:var(--blue); color:#fff;
  transition:transform .1s ease, opacity .1s ease;
}
.btn:hover{transform:translateY(-1px); text-decoration:none; opacity:.95;}
.btn.secondary{background:#fff; color:var(--ink); border-color:var(--border);}
.btn.secondary:hover{border-color:var(--blue); color:var(--blue);}
.btn.amber{background:var(--amber); border-color:var(--amber); color:var(--ink);}
.btn.block{width:100%; justify-content:center;}
.btn:disabled{opacity:.5; cursor:not-allowed; transform:none;}

section{padding:60px 0;}
section.alt{background:var(--bg-alt);}
.section-head{text-align:center; max-width:640px; margin:0 auto 40px;}
.section-head p{font-size:1.05rem;}

.grid{display:grid; gap:22px;}
.grid.cols-2{grid-template-columns:repeat(2,1fr);}
.grid.cols-3{grid-template-columns:repeat(3,1fr);}
.grid.cols-4{grid-template-columns:repeat(4,1fr);}
@media (max-width:900px){ .grid.cols-3,.grid.cols-4{grid-template-columns:repeat(2,1fr);} }
@media (max-width:640px){ .grid.cols-2,.grid.cols-3,.grid.cols-4{grid-template-columns:1fr;} }

.card{background:#fff; border:1px solid var(--border); border-radius:var(--radius); padding:28px; box-shadow:var(--shadow);}
.card .icon{
  width:52px; height:52px; border-radius:12px; background:var(--blue-50); color:var(--blue);
  display:flex; align-items:center; justify-content:center; margin-bottom:18px;
}
.card .icon svg{width:26px;height:26px;}
.card h3{margin-bottom:8px;}
.card p{font-size:.94rem; margin-bottom:14px;}
.card a.go{font-weight:700; font-size:.9rem;}
.card .tag{display:inline-block; font-size:.72rem; font-weight:700; text-transform:uppercase; letter-spacing:.04em; color:var(--blue); background:var(--blue-50); padding:4px 10px; border-radius:100px; margin-bottom:10px;}

/* Steps */
.steps-row{display:grid; grid-template-columns:repeat(3,1fr); gap:0; text-align:center; position:relative;}
@media (max-width:760px){ .steps-row{grid-template-columns:1fr; gap:36px;} }
.step-circle{
  width:78px; height:78px; border-radius:50%; border:2px solid var(--blue-50); background:#fff;
  display:flex; align-items:center; justify-content:center; font-size:1.6rem; font-weight:800; color:var(--blue);
  margin:0 auto 18px; position:relative; z-index:1;
}
.steps-row .step h3{margin-bottom:8px;}
.steps-row .step p{font-size:.92rem; max-width:26ch; margin:0 auto;}

.stats-row{display:grid; grid-template-columns:repeat(4,1fr); gap:20px; text-align:center; padding-top:50px;}
@media (max-width:700px){ .stats-row{grid-template-columns:repeat(2,1fr);} }
.stat .num{font-size:2.4rem; font-weight:900; color:var(--ink);}
.stat .label{color:var(--blue); font-weight:600; font-size:.95rem;}

.check-grid{display:grid; grid-template-columns:repeat(3,1fr); gap:14px 32px;}
@media (max-width:760px){ .check-grid{grid-template-columns:1fr;} }
.check-item{display:flex; align-items:center; gap:10px; font-weight:700; font-size:.95rem;}
.check-item svg{width:19px;height:19px; color:var(--blue); flex-shrink:0;}

.pill-row{display:flex; flex-wrap:wrap; gap:14px; justify-content:center;}
.pill{
  border:1.5px solid var(--border); border-radius:100px; padding:12px 24px; font-weight:700; font-size:.95rem; background:#fff;
}

/* Forms / generator */
.field{display:flex; flex-direction:column; gap:7px; font-size:.85rem; font-weight:700; color:var(--ink);}
.field select, .field input, .field textarea{
  padding:11px 12px; border:1.5px solid var(--border); border-radius:10px; background:#fff; font-size:.95rem;
  font-family:'Inter',sans-serif; color:var(--ink);
}
.field select:focus, .field input:focus, .field textarea:focus{border-color:var(--blue);}
.tool-layout{display:grid; grid-template-columns:1fr 320px; gap:26px; align-items:start;}
@media (max-width:900px){ .tool-layout{grid-template-columns:1fr;} }
.step-num{
  width:28px;height:28px;border-radius:50%; background:var(--blue-50); color:var(--blue); font-weight:800; font-size:.85rem;
  display:inline-flex; align-items:center; justify-content:center; margin-right:10px;
}
.tool-section-title{display:flex; align-items:center; margin:0 0 18px; font-size:1.05rem;}
hr.tool-div{border:none; border-top:1px solid var(--border); margin:26px 0;}
.feature-list{list-style:none; padding:0; margin:0; display:flex; flex-direction:column; gap:12px; font-size:.9rem;}
.feature-list li{display:flex; gap:9px; align-items:flex-start;}
.feature-list svg{width:16px;height:16px; color:var(--blue); flex-shrink:0; margin-top:3px;}
.ad-slot{
  border:1.5px dashed var(--border); border-radius:12px; padding:26px 14px; text-align:center; color:var(--muted);
  font-size:.85rem; margin-top:20px; background:var(--bg-alt);
}
.ad-slot .lbl{font-size:.7rem; text-transform:uppercase; letter-spacing:.08em; color:#94A3B8; margin-bottom:10px;}

.problem-sheet{background:#fff; border:1.5px solid var(--border); border-radius:var(--radius); padding:28px; box-shadow:var(--shadow);}
.sheet-header{display:flex; justify-content:space-between; align-items:center; border-bottom:1px solid var(--border); padding-bottom:14px; margin-bottom:18px; font-size:.85rem; color:var(--muted);}
.problems{display:grid; grid-template-columns:repeat(3,1fr); gap:16px 20px;}
@media (max-width:700px){ .problems{grid-template-columns:repeat(2,1fr);} }
.problem{font-size:1.02rem; display:flex; align-items:baseline; gap:8px;}
.problem .idx{color:var(--muted); font-size:.8rem; width:1.4em;}
.answer-box{width:2.4em; display:inline-block; border:1.5px solid var(--border); border-radius:6px; padding:5px 6px; text-align:center; background:#fff;}

/* Practice quiz */
.quiz-q{background:#fff; border:1.5px solid var(--border); border-radius:14px; padding:20px 22px; margin-bottom:14px;}
.quiz-q .qtext{font-weight:700; font-size:1.05rem; margin-bottom:12px;}
.quiz-q input{width:140px;}
.quiz-q.correct{border-color:var(--green); background:#F0FDF4;}
.quiz-q.incorrect{border-color:#DC2626; background:#FEF2F2;}
.quiz-score{
  background:var(--blue-50); border:1.5px solid var(--blue); border-radius:14px; padding:22px; text-align:center; margin-top:18px;
}
.quiz-score .big{font-size:2.2rem; font-weight:900; color:var(--blue);}

/* Calculators */
.calc-layout{display:grid; grid-template-columns:260px 1fr; gap:26px; align-items:start;}
@media (max-width:860px){ .calc-layout{grid-template-columns:1fr;} }
.calc-nav{display:flex; flex-direction:column; gap:4px; position:sticky; top:90px;}
@media (max-width:860px){ .calc-nav{position:static; flex-direction:row; flex-wrap:wrap;} }
.calc-nav button{
  text-align:left; background:none; border:none; padding:10px 14px; border-radius:10px; font-weight:600; font-size:.92rem;
  color:var(--ink-soft); cursor:pointer;
}
.calc-nav button:hover{background:var(--bg-alt);}
.calc-nav button.active{background:var(--blue-50); color:var(--blue);}
.calc-panel{display:none;}
.calc-panel.active{display:block;}
.calc-form{display:grid; grid-template-columns:repeat(2,1fr); gap:16px; margin-bottom:18px;}
@media (max-width:600px){ .calc-form{grid-template-columns:1fr;} }
.calc-result{background:var(--blue-50); border:1.5px solid var(--blue); border-radius:12px; padding:18px 20px; margin-top:6px;}
.calc-result .val{font-size:1.5rem; font-weight:800; color:var(--blue-dark);}
.calc-result .steps{font-size:.85rem; color:var(--ink-soft); margin-top:8px; white-space:pre-line;}
.err{color:#DC2626; font-size:.85rem; margin-top:6px;}

/* Blog */
.blog-card .cat{color:var(--blue); font-weight:700; font-size:.85rem; margin-bottom:8px; display:block;}
.blog-card h3{margin-bottom:10px;}
.blog-card p{font-size:.93rem;}
article.post{max-width:740px; margin:0 auto;}
article.post h2{margin-top:1.4em;}
article.post p{font-size:1.02rem; color:var(--ink-soft);}

.breadcrumbs{font-size:.85rem; color:var(--muted); margin-bottom:18px;}
.breadcrumbs a{color:var(--muted);}

/* Footer */
footer{background:var(--navy); color:#CBD5E1; padding:56px 0 30px; margin-top:20px;}
.foot-grid{display:grid; grid-template-columns:1.6fr 1fr 1fr; gap:30px;}
@media (max-width:760px){ .foot-grid{grid-template-columns:1fr 1fr;} }
.foot-grid h4{color:#fff; font-size:.85rem; text-transform:uppercase; letter-spacing:.06em; margin-bottom:14px;}
.foot-grid ul{list-style:none; padding:0; margin:0; display:flex; flex-direction:column; gap:9px; font-size:.92rem;}
.foot-grid a{color:#CBD5E1;}
.foot-grid a:hover{color:#fff;}
.foot-brand{display:flex; align-items:center; gap:10px; color:#fff; font-weight:800; font-size:1.1rem; margin-bottom:14px;}
.foot-brand .mark{width:38px;height:38px; border-radius:50%; background:#fff; display:flex; align-items:center; justify-content:center;}
.foot-brand .mark svg{width:20px;height:20px;}
.foot-bottom{max-width:var(--max); margin:34px auto 0; padding:20px 24px 0; border-top:1px solid rgba(255,255,255,.1); font-size:.8rem; color:#94A3B8;}

.support-float{
  position:fixed; right:22px; bottom:22px; background:var(--amber); color:var(--ink); font-weight:800; font-size:.9rem;
  padding:13px 20px; border-radius:100px; box-shadow:0 8px 22px rgba(0,0,0,.18); z-index:40; display:flex; align-items:center; gap:8px;
}
.support-float:hover{text-decoration:none; opacity:.92;}

.notice{background:#FFFBEB; border:1px solid #FDE68A; border-radius:10px; padding:14px 16px; font-size:.88rem; margin:20px 0;}