style.css

/* ESD Study Guide — Shared Styles */
:root{
  --bg:#FAFAF7;--surface:#FFF;--s2:#F3F3EE;--border:#E2E2D8;
  --text:#1A1A1A;--muted:#6B6B60;
  --green:#2D6A4F;--dgreen:#1B4332;--lgreen:#40916C;
  --orange:#E76F51;--blue:#457B9D;--purple:#7B2D8B;--yellow:#F4A261;
  --gl:#D8F3DC;--rl:#FFE8E8;--bl:#E8F0FF;--pl:#F0E8FF;--yl:#FFF3CD;
}
*{box-sizing:border-box;margin:0;padding:0}
body{background:var(--bg);color:var(--text);font-family:'DM Sans',sans-serif;font-size:15px;line-height:1.7}

/* NAV */
nav{position:sticky;top:0;z-index:100;background:rgba(250,250,247,.97);backdrop-filter:blur(10px);border-bottom:2px solid var(--green);display:flex;align-items:center;overflow-x:auto;scrollbar-width:none;padding:0 12px}
nav::-webkit-scrollbar{display:none}
.nav-logo{font-family:'Playfair Display',serif;font-weight:900;font-size:14px;color:var(--green);white-space:nowrap;padding:12px 10px 12px 0;border-right:1px solid var(--border);margin-right:4px;flex-shrink:0;text-decoration:none}
nav a{text-decoration:none;color:var(--muted);font-size:11px;font-weight:600;white-space:nowrap;padding:14px 8px;border-bottom:2px solid transparent;transition:all .2s;flex-shrink:0}
nav a:hover,nav a.active{color:var(--green);border-bottom-color:var(--green)}

/* HERO */
.hero{background:linear-gradient(135deg,#1B4332,#2D6A4F 50%,#40916C);color:#fff;padding:52px 28px;text-align:center;position:relative;overflow:hidden}
.hero::before{content:'';position:absolute;inset:0;background:repeating-linear-gradient(45deg,transparent,transparent 40px,rgba(255,255,255,.03) 40px,rgba(255,255,255,.03) 80px)}
.hero-badge{display:inline-block;background:rgba(255,255,255,.15);border:1px solid rgba(255,255,255,.3);border-radius:20px;padding:4px 14px;font-size:11px;font-weight:700;letter-spacing:1px;margin-bottom:12px}
.hero h1{font-family:'Playfair Display',serif;font-size:clamp(24px,5vw,46px);font-weight:900;line-height:1.15;margin-bottom:10px;position:relative}
.hero p{opacity:.85;font-size:14px;max-width:560px;margin:0 auto 20px;position:relative}
.hero-stats{display:flex;justify-content:center;gap:24px;flex-wrap:wrap;position:relative}
.stat .n{font-family:'Playfair Display',serif;font-size:24px;font-weight:900;display:block}
.stat .l{font-size:10px;opacity:.7;letter-spacing:.5px}

/* PAGE NAV BUTTONS */
.page-nav{display:flex;gap:10px;flex-wrap:wrap;margin:24px 0 8px}
.page-nav a{display:inline-flex;align-items:center;gap:6px;text-decoration:none;background:var(--surface);border:1.5px solid var(--border);border-radius:8px;padding:8px 14px;font-size:12px;font-weight:700;color:var(--green);transition:all .2s}
.page-nav a:hover{background:var(--gl);border-color:var(--green)}
.page-nav a.active{background:var(--green);color:#fff;border-color:var(--green)}

/* CONTAINER */
.container{max-width:920px;margin:0 auto;padding:0 18px}
section{padding:40px 0;border-bottom:1px solid var(--border)}
section:last-of-type{border-bottom:none}

/* SECTION HEADER */
.sec-head{display:flex;align-items:center;gap:10px;flex-wrap:wrap;margin-bottom:5px}
.sec-head h2{font-family:'Playfair Display',serif;font-size:25px;font-weight:900;color:var(--green)}
.wk{background:var(--green);color:#fff;font-size:12px;font-family:'DM Mono',monospace;padding:2px 10px;border-radius:4px;font-weight:500}
.sec-sub{color:var(--muted);font-size:12px;margin-bottom:20px;font-weight:500}

/* ANALOGY BOX */
.analogy{background:var(--yl);border:1px solid #FFD93D;border-left:4px solid var(--yellow);border-radius:8px;padding:14px 16px;margin:14px 0;display:flex;gap:10px}
.analogy .ic{font-size:22px;flex-shrink:0;margin-top:1px}
.analogy strong{color:var(--orange);font-size:11px;letter-spacing:.5px;text-transform:uppercase;display:block;margin-bottom:3px}
.analogy p{font-size:13px;line-height:1.65}

/* CARDS */
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(210px,1fr));gap:12px;margin:16px 0}
.card{background:var(--surface);border:1px solid var(--border);border-radius:10px;padding:16px;transition:box-shadow .2s,transform .2s}
.card:hover{box-shadow:0 4px 14px rgba(0,0,0,.08);transform:translateY(-2px)}
.card .ci{font-size:22px;margin-bottom:7px;display:block}
.card h4{font-weight:700;font-size:13px;margin-bottom:5px}
.card p{font-size:12.5px;color:var(--muted);line-height:1.6}
.card.g{border-left:4px solid var(--green)}
.card.o{border-left:4px solid var(--orange)}
.card.b{border-left:4px solid var(--blue)}
.card.p{border-left:4px solid var(--purple)}
.card.y{border-left:4px solid var(--yellow)}

/* DIAGRAM */
.diag{background:var(--surface);border:1px solid var(--border);border-radius:10px;padding:18px;margin:14px 0;overflow-x:auto}
.diag-t{font-weight:700;font-size:11px;color:var(--muted);letter-spacing:.5px;text-transform:uppercase;margin-bottom:12px}
.flow{display:flex;align-items:center;gap:7px;flex-wrap:wrap;justify-content:center}
.fb{background:var(--green);color:#fff;border-radius:7px;padding:8px 13px;font-size:12px;font-weight:600;text-align:center;min-width:90px}
.fb.o{background:var(--orange)}.fb.b{background:var(--blue)}.fb.p{background:var(--purple)}
.fb.li{background:var(--gl);color:var(--green);border:1px solid var(--green)}
.fa{color:var(--muted);font-size:15px;font-weight:700}

/* SDG GRID */
.sdgs{display:grid;grid-template-columns:repeat(auto-fill,minmax(145px,1fr));gap:9px;margin:14px 0}
.sdg{border-radius:7px;padding:9px;font-size:11px;font-weight:600;display:flex;align-items:flex-start;gap:6px;border:1px solid transparent}
.sdg .sn{font-family:'DM Mono',monospace;font-size:15px;font-weight:700;flex-shrink:0}

/* Q&A */
.qas{margin:16px 0}
.qa{border:1px solid var(--border);border-radius:8px;margin-bottom:9px;overflow:hidden}
.qq{background:var(--s2);padding:12px 15px;font-weight:600;font-size:13.5px;cursor:pointer;display:flex;justify-content:space-between;align-items:center;gap:10px;user-select:none}
.qq:hover{background:var(--gl)}
.qq::after{content:'▼';font-size:10px;color:var(--muted);transition:transform .3s;flex-shrink:0}
.qa.open .qq::after{transform:rotate(180deg)}
.qa .ans{display:none;padding:12px 15px;font-size:13px;line-height:1.8;border-top:1px solid var(--border);background:#fff}
.qa.open .ans{display:block}
.qa .ans strong{color:var(--green)}
.qa .ans .correct{background:var(--gl);color:var(--dgreen);font-weight:700;padding:3px 9px;border-radius:4px;display:inline-block;margin:3px 0}

/* ASSIGNMENT BLOCK */
.asgn-section{background:var(--bl);border:1.5px solid var(--blue);border-radius:10px;padding:20px;margin:16px 0}
.asgn-section h3{color:var(--blue);font-family:'Playfair Display',serif;font-size:17px;margin-bottom:14px;display:flex;align-items:center;gap:8px}
.asgn-q{border:1px solid rgba(69,123,157,.3);border-radius:7px;margin-bottom:8px;overflow:hidden;background:#fff}
.asgn-q .qqq{padding:11px 14px;font-weight:600;font-size:13px;cursor:pointer;display:flex;justify-content:space-between;align-items:flex-start;gap:10px;user-select:none}
.asgn-q .qqq:hover{background:rgba(69,123,157,.06)}
.asgn-q .qqq::after{content:'▼';font-size:10px;color:var(--blue);transition:transform .3s;flex-shrink:0;margin-top:3px}
.asgn-q.open .qqq::after{transform:rotate(180deg)}
.asgn-q .aaa{display:none;padding:11px 14px;font-size:13px;border-top:1px solid rgba(69,123,157,.2);line-height:1.7}
.asgn-q.open .aaa{display:block}

/* CASE STUDY */
.case{background:var(--pl);border:1.5px solid var(--purple);border-radius:10px;padding:18px;margin:14px 0}
.case h4{color:var(--purple);font-weight:800;font-size:14px;margin-bottom:10px;display:flex;align-items:center;gap:7px}
.case-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin-top:10px}
.case-col{background:#fff;border-radius:7px;padding:11px;font-size:12px}
.case-col strong{display:block;font-size:10px;letter-spacing:.5px;text-transform:uppercase;color:var(--purple);margin-bottom:4px}

/* IMPORTANT BOX */
.imp{background:linear-gradient(135deg,#1B4332,#2D6A4F);color:#fff;border-radius:10px;padding:20px 24px;margin-top:26px}
.imp h3{font-family:'Playfair Display',serif;font-size:16px;margin-bottom:12px;display:flex;align-items:center;gap:7px}
.imp ul{list-style:none;padding:0}
.imp li{padding:4px 0;font-size:12.5px;display:flex;gap:9px;line-height:1.6;opacity:.92}
.imp li::before{content:'★';color:var(--yellow);flex-shrink:0}

/* TABLE */
table{width:100%;border-collapse:collapse;margin:12px 0;font-size:13px}
th{background:var(--green);color:#fff;padding:9px 12px;text-align:left;font-weight:600}
td{padding:9px 12px;border-bottom:1px solid var(--border)}
tr:nth-child(even) td{background:var(--s2)}

/* TAG */
.tag{display:inline-block;background:var(--gl);color:var(--green);border-radius:4px;padding:1px 7px;font-size:11px;font-weight:700;margin:2px}
.tag.o{background:#FFE8D6;color:#C05621}.tag.b{background:var(--bl);color:var(--blue)}.tag.r{background:var(--rl);color:#c0392b}

/* FOOTER */
footer{background:#1A1A1A;color:#aaa;text-align:center;padding:24px;font-size:13px;margin-top:40px}
footer strong{color:#fff}
footer a{color:var(--lgreen);text-decoration:none}

/* SVG */
svg text{font-family:'DM Sans',sans-serif}

/* RESPONSIVE */
@media(max-width:600px){
  .hero{padding:36px 16px}.cards{grid-template-columns:1fr}
  .sdgs{grid-template-columns:repeat(2,1fr)}.flow{flex-direction:column}
  .fa{transform:rotate(90deg)}.case-grid{grid-template-columns:1fr}
  .page-nav{gap:6px}.page-nav a{padding:6px 10px;font-size:11px}
}
@media print{nav,.page-nav{display:none}.ans,.aaa{display:block!important}}