/* ============================================================
   CalcHub - Main Stylesheet
   Primary: #2563eb | Clean Modern Design
   ============================================================ */

:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --primary-light: #eff6ff;
  --primary-border: #bfdbfe;
  --secondary: #64748b;
  --success: #16a34a;
  --success-bg: #f0fdf4;
  --warning: #d97706;
  --warning-bg: #fffbeb;
  --danger: #dc2626;
  --danger-bg: #fef2f2;
  --text: #0f172a;
  --text-muted: #64748b;
  --text-light: #94a3b8;
  --bg: #ffffff;
  --bg-soft: #f8fafc;
  --bg-gray: #f1f5f9;
  --border: #e2e8f0;
  --border-dark: #cbd5e1;
  --radius: 8px;
  --radius-lg: 12px;
  --shadow: 0 1px 3px rgba(0,0,0,0.1);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.07);
  --shadow-lg: 0 10px 15px rgba(0,0,0,0.08);
  --font: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
  --max-width: 1200px;
}

*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{font-family:var(--font);color:var(--text);background:var(--bg);line-height:1.6;-webkit-font-smoothing:antialiased}
img{max-width:100%;display:block}
a{color:var(--primary);text-decoration:none}
a:hover{text-decoration:underline}
button{cursor:pointer;font-family:var(--font)}
input,select,textarea{font-family:var(--font)}
h1,h2,h3,h4{font-weight:600;line-height:1.3;color:var(--text)}
h1{font-size:2rem}h2{font-size:1.5rem}h3{font-size:1.2rem}
p{margin-bottom:1rem;color:var(--text-muted);line-height:1.75}
p:last-child{margin-bottom:0}
ul,ol{padding-left:1.5rem;color:var(--text-muted)}
ul li,ol li{margin-bottom:.4rem;line-height:1.7}
strong{color:var(--text);font-weight:600}
code{font-family:var(--font-mono);font-size:.875em;background:var(--bg-gray);padding:.15em .4em;border-radius:4px;color:var(--primary-dark)}

/* HEADER */
.site-header{background:#fff;border-bottom:1px solid var(--border);position:sticky;top:0;z-index:100;height:64px}
.header-inner{max-width:var(--max-width);margin:0 auto;padding:0 1.5rem;height:100%;display:flex;align-items:center;justify-content:space-between;gap:1rem}
.logo{font-size:1.35rem;font-weight:700;color:var(--text);text-decoration:none;display:flex;align-items:center;gap:.4rem;flex-shrink:0}
.logo:hover{text-decoration:none}
.logo-icon{width:32px;height:32px;background:var(--primary);border-radius:7px;display:flex;align-items:center;justify-content:center;color:white;font-size:1rem}
.logo span{color:var(--primary)}
.header-search{flex:1;max-width:420px;position:relative}
.header-search input{width:100%;padding:.55rem 1rem .55rem 2.6rem;border:1.5px solid var(--border);border-radius:100px;font-size:.9rem;outline:none;background:var(--bg-soft);transition:border-color .2s}
.header-search input:focus{border-color:var(--primary);background:#fff}
.header-search input::placeholder{color:var(--text-light)}
.header-search .search-icon{position:absolute;left:.85rem;top:50%;transform:translateY(-50%);color:var(--text-light);pointer-events:none}
.header-nav{display:flex;align-items:center;gap:.25rem}
.header-nav a{padding:.4rem .75rem;border-radius:var(--radius);font-size:.875rem;font-weight:500;color:var(--text-muted);transition:background .15s,color .15s;text-decoration:none;white-space:nowrap}
.header-nav a:hover{background:var(--bg-soft);color:var(--text);text-decoration:none}

/* BREADCRUMB */
.breadcrumb-bar{background:var(--bg-soft);border-bottom:1px solid var(--border);padding:.6rem 0}
.breadcrumb{max-width:var(--max-width);margin:0 auto;padding:0 1.5rem;display:flex;align-items:center;gap:.4rem;font-size:.82rem;color:var(--text-muted);flex-wrap:wrap}
.breadcrumb a{color:var(--text-muted)}
.breadcrumb a:hover{color:var(--primary)}
.breadcrumb .sep{color:var(--text-light)}
.breadcrumb .current{color:var(--text);font-weight:500}

/* SHARE BAR */
.share-bar{background:var(--primary-light);border-bottom:1px solid var(--primary-border);padding:.6rem 0}
.share-bar-inner{max-width:var(--max-width);margin:0 auto;padding:0 1.5rem;display:flex;align-items:center;gap:.75rem;flex-wrap:wrap}
.share-label{font-size:.82rem;font-weight:600;color:var(--primary-dark)}
.share-btn{display:inline-flex;align-items:center;gap:.35rem;padding:.3rem .75rem;border-radius:100px;font-size:.78rem;font-weight:500;border:none;cursor:pointer;transition:opacity .15s,transform .15s;text-decoration:none}
.share-btn:hover{opacity:.88;transform:translateY(-1px);text-decoration:none}
.share-btn.facebook{background:#1877f2;color:white}
.share-btn.twitter{background:#000;color:white}
.share-btn.whatsapp{background:#25d366;color:white}
.share-btn.copy{background:var(--bg);color:var(--text);border:1.5px solid var(--border)}

/* LAYOUT */
.page-layout{max-width:var(--max-width);margin:0 auto;padding:2rem 1.5rem;display:grid;grid-template-columns:1fr 300px;gap:2rem;align-items:start}

/* TOOL HEADER */
.tool-header{margin-bottom:1.5rem}
.tool-category-tag{display:inline-flex;align-items:center;gap:.3rem;background:var(--primary-light);color:var(--primary);border:1px solid var(--primary-border);padding:.25rem .75rem;border-radius:100px;font-size:.78rem;font-weight:600;margin-bottom:.75rem;text-decoration:none}
.tool-category-tag:hover{background:var(--primary);color:white;text-decoration:none}
.tool-header h1{font-size:1.85rem;margin-bottom:.5rem}
.tool-header .subtitle{color:var(--text-muted);font-size:1rem;margin-bottom:.5rem;line-height:1.6}
.tool-meta{display:flex;align-items:center;gap:1rem;font-size:.8rem;color:var(--text-light);flex-wrap:wrap}

/* CALCULATOR CARD */
.calc-card{background:var(--bg);border:1.5px solid var(--border);border-radius:var(--radius-lg);overflow:hidden;box-shadow:var(--shadow-md);margin-bottom:2rem}
.calc-card-header{background:var(--primary);color:white;padding:1rem 1.5rem;font-weight:600;font-size:.95rem;display:flex;align-items:center;gap:.5rem}
.calc-card-body{padding:1.5rem}
.input-row{display:grid;grid-template-columns:1fr 1fr;gap:1rem;margin-bottom:1rem}
.input-row.single{grid-template-columns:1fr}
.input-row.triple{grid-template-columns:1fr 1fr 1fr}
.form-group{display:flex;flex-direction:column;gap:.35rem}
.form-label{font-size:.82rem;font-weight:600;color:var(--text);display:flex;align-items:center;gap:.3rem}
.form-input,.form-select{padding:.65rem .9rem;border:1.5px solid var(--border);border-radius:var(--radius);font-size:.925rem;color:var(--text);background:var(--bg);outline:none;transition:border-color .2s,box-shadow .2s;width:100%}
.form-input:focus,.form-select:focus{border-color:var(--primary);box-shadow:0 0 0 3px rgba(37,99,235,.1)}
.form-input::placeholder{color:var(--text-light)}
.unit-toggle{display:flex;background:var(--bg-gray);border-radius:var(--radius);padding:3px;gap:3px;margin-bottom:1rem}
.unit-toggle button{flex:1;padding:.45rem .5rem;border:none;border-radius:6px;font-size:.82rem;font-weight:500;background:transparent;color:var(--text-muted);transition:all .15s}
.unit-toggle button.active{background:#fff;color:var(--primary);font-weight:600;box-shadow:var(--shadow)}
.calc-actions{display:flex;gap:.75rem;margin-top:1.25rem}
.btn-calc{flex:1;padding:.8rem 1.5rem;background:var(--primary);color:white;border:none;border-radius:var(--radius);font-size:.95rem;font-weight:600;transition:background .2s,transform .15s}
.btn-calc:hover{background:var(--primary-dark);transform:translateY(-1px)}
.btn-reset{padding:.8rem 1.2rem;background:var(--bg-soft);color:var(--text-muted);border:1.5px solid var(--border);border-radius:var(--radius);font-size:.875rem;font-weight:500;transition:all .2s}
.btn-reset:hover{border-color:var(--border-dark);color:var(--text)}

/* RESULTS */
.result-section{margin-top:1.5rem;display:none}
.result-section.visible{display:block}
.result-primary{background:var(--primary-light);border:1.5px solid var(--primary-border);border-radius:var(--radius-lg);padding:1.25rem 1.5rem;margin-bottom:1rem;display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:.5rem}
.result-primary .label{font-size:.85rem;font-weight:600;color:var(--primary-dark)}
.result-primary .value{font-size:1.75rem;font-weight:700;color:var(--primary)}
.result-primary .sub{font-size:.82rem;color:var(--primary-dark);opacity:.8;width:100%}
.result-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(140px,1fr));gap:.75rem;margin-bottom:1rem}
.result-item{background:var(--bg-soft);border:1px solid var(--border);border-radius:var(--radius);padding:.85rem 1rem}
.result-item .r-label{font-size:.75rem;font-weight:600;color:var(--text-light);text-transform:uppercase;letter-spacing:.04em;margin-bottom:.25rem}
.result-item .r-value{font-size:1.1rem;font-weight:700;color:var(--text)}
.result-item.green{background:var(--success-bg);border-color:#bbf7d0}
.result-item.green .r-value{color:var(--success)}
.result-item.yellow{background:var(--warning-bg);border-color:#fde68a}
.result-item.yellow .r-value{color:var(--warning)}
.result-item.red{background:var(--danger-bg);border-color:#fecaca}
.result-item.red .r-value{color:var(--danger)}

/* BREAKDOWN TABLE */
.breakdown-table{width:100%;border-collapse:collapse;font-size:.875rem;margin-top:1rem;border-radius:var(--radius);overflow:hidden;border:1px solid var(--border)}
.breakdown-table thead{background:var(--bg-gray)}
.breakdown-table th{padding:.7rem 1rem;text-align:left;font-size:.78rem;font-weight:600;color:var(--text);text-transform:uppercase;letter-spacing:.04em;border-bottom:1px solid var(--border)}
.breakdown-table td{padding:.65rem 1rem;border-bottom:1px solid var(--border);color:var(--text-muted)}
.breakdown-table tr:last-child td{border-bottom:none}
.breakdown-table tr:hover td{background:var(--bg-soft)}
.breakdown-table .total td{font-weight:700;color:var(--text);background:var(--bg-soft)}

/* CHART */
.chart-card{background:var(--bg);border:1.5px solid var(--border);border-radius:var(--radius-lg);padding:1.25rem;margin-bottom:2rem}
.chart-title{font-size:.95rem;font-weight:600;color:var(--text);margin-bottom:1rem}
.chart-wrap{position:relative;height:260px}

/* TABLE OF CONTENTS */
.toc-card{background:var(--primary-light);border:1px solid var(--primary-border);border-radius:var(--radius-lg);padding:1.25rem;margin-bottom:2rem}
.toc-title{font-size:.95rem;font-weight:700;color:var(--primary-dark);margin-bottom:.75rem}
.toc-list{list-style:none;padding:0;counter-reset:toc}
.toc-list li{counter-increment:toc}
.toc-list li a{display:flex;align-items:center;gap:.6rem;padding:.3rem 0;font-size:.875rem;color:var(--primary-dark);text-decoration:none;border-bottom:1px dashed var(--primary-border)}
.toc-list li:last-child a{border-bottom:none}
.toc-list li a::before{content:counter(toc);min-width:20px;height:20px;background:var(--primary);color:white;border-radius:50%;font-size:.7rem;font-weight:700;display:flex;align-items:center;justify-content:center;flex-shrink:0}
.toc-list li a:hover{color:var(--primary)}

/* CONTENT */
.content-body{font-size:.95rem}
.content-section{margin-bottom:2.5rem}
.content-section h2{font-size:1.35rem;font-weight:700;margin-bottom:1rem;padding-bottom:.5rem;border-bottom:2px solid var(--primary-light);display:flex;align-items:center;gap:.5rem}
.content-section h2::before{content:'';width:4px;height:1.35rem;background:var(--primary);border-radius:2px;flex-shrink:0}
.content-section h3{font-size:1.1rem;font-weight:600;margin-bottom:.75rem;margin-top:1.25rem}
.formula-box{background:var(--bg-gray);border-left:4px solid var(--primary);border-radius:0 var(--radius) var(--radius) 0;padding:1rem 1.25rem;margin:1rem 0;font-family:var(--font-mono);font-size:.9rem}
.formula-box .formula-label{font-family:var(--font);font-size:.78rem;font-weight:600;color:var(--text-light);text-transform:uppercase;letter-spacing:.05em;margin-bottom:.4rem}
.info-box{background:var(--primary-light);border:1px solid var(--primary-border);border-radius:var(--radius);padding:1rem 1.25rem;margin:1rem 0;font-size:.9rem;color:var(--primary-dark)}

/* FAQ */
.faq-item{border:1px solid var(--border);border-radius:var(--radius);margin-bottom:.75rem;overflow:hidden}
.faq-question{width:100%;text-align:left;padding:1rem 1.25rem;background:var(--bg-soft);border:none;font-size:.925rem;font-weight:600;color:var(--text);cursor:pointer;display:flex;justify-content:space-between;align-items:center;gap:.5rem;transition:background .15s}
.faq-question:hover{background:var(--bg-gray)}
.faq-question.open{background:var(--primary-light);color:var(--primary-dark)}
.faq-arrow{font-size:.8rem;transition:transform .2s;flex-shrink:0;color:var(--text-light)}
.faq-question.open .faq-arrow{transform:rotate(180deg);color:var(--primary)}
.faq-answer{padding:0 1.25rem;max-height:0;overflow:hidden;transition:max-height .3s ease,padding .2s;font-size:.9rem;color:var(--text-muted);line-height:1.7}
.faq-answer.open{max-height:400px;padding:1rem 1.25rem}

/* SIDEBAR */
.sidebar{display:flex;flex-direction:column;gap:1.25rem}
.sidebar-card{background:var(--bg);border:1.5px solid var(--border);border-radius:var(--radius-lg);overflow:hidden}
.sidebar-card-header{background:var(--bg-gray);padding:.85rem 1.1rem;font-size:.85rem;font-weight:700;color:var(--text);border-bottom:1px solid var(--border);display:flex;align-items:center;gap:.4rem}
.related-tool-link{display:flex;align-items:center;gap:.75rem;padding:.75rem 1.1rem;border-bottom:1px solid var(--border);text-decoration:none;transition:background .15s}
.related-tool-link:last-child{border-bottom:none}
.related-tool-link:hover{background:var(--bg-soft);text-decoration:none}
.related-tool-icon{width:34px;height:34px;background:var(--primary-light);border-radius:var(--radius);display:flex;align-items:center;justify-content:center;font-size:1rem;flex-shrink:0}
.related-tool-name{font-size:.85rem;font-weight:500;color:var(--text);line-height:1.3}
.related-tool-cat{font-size:.75rem;color:var(--text-light)}
.category-grid-sidebar{display:grid;grid-template-columns:1fr 1fr;gap:.5rem;padding:.85rem}
.cat-btn-sidebar{display:flex;flex-direction:column;align-items:center;gap:.3rem;padding:.65rem .5rem;background:var(--bg-soft);border:1px solid var(--border);border-radius:var(--radius);text-decoration:none;font-size:.75rem;font-weight:500;color:var(--text-muted);transition:all .15s;text-align:center}
.cat-btn-sidebar:hover{background:var(--primary-light);color:var(--primary);border-color:var(--primary-border);text-decoration:none}
.cat-btn-sidebar .cat-icon{font-size:1.2rem}

/* HOMEPAGE */
.hero{background:linear-gradient(135deg,#1e40af 0%,#2563eb 50%,#3b82f6 100%);color:white;padding:4rem 1.5rem;text-align:center}
.hero h1{font-size:2.5rem;color:white;margin-bottom:1rem}
.hero p{color:rgba(255,255,255,.88);font-size:1.1rem;max-width:560px;margin:0 auto 2rem}
.hero-search{max-width:520px;margin:0 auto;position:relative}
.hero-search input{width:100%;padding:1rem 1rem 1rem 3rem;border-radius:100px;border:none;font-size:1rem;outline:none;box-shadow:var(--shadow-lg)}
.hero-search .s-icon{position:absolute;left:1.1rem;top:50%;transform:translateY(-50%);font-size:1rem;color:var(--text-light)}
.hero-stats{display:flex;justify-content:center;gap:3rem;margin-top:2.5rem;flex-wrap:wrap}
.hero-stat{color:rgba(255,255,255,.9)}
.hero-stat .num{font-size:1.8rem;font-weight:700;color:white;line-height:1}
.hero-stat .lbl{font-size:.82rem;opacity:.8}
.homepage-body{max-width:var(--max-width);margin:0 auto;padding:3rem 1.5rem}
.section-header{display:flex;align-items:baseline;justify-content:space-between;margin-bottom:1.25rem}
.section-title{font-size:1.25rem;font-weight:700;color:var(--text)}
.see-all{font-size:.875rem;color:var(--primary);font-weight:500}
.tools-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:1rem;margin-bottom:3rem}
.tool-card{background:var(--bg);border:1.5px solid var(--border);border-radius:var(--radius-lg);padding:1.15rem;text-decoration:none;display:flex;flex-direction:column;gap:.5rem;transition:border-color .2s,box-shadow .2s,transform .2s}
.tool-card:hover{border-color:var(--primary);box-shadow:var(--shadow-md);transform:translateY(-2px);text-decoration:none}
.tool-card-icon{font-size:1.6rem;margin-bottom:.1rem}
.tool-card-name{font-size:.92rem;font-weight:600;color:var(--text);line-height:1.3}
.tool-card-desc{font-size:.8rem;color:var(--text-muted);line-height:1.5;flex:1}
.tool-card-tag{font-size:.7rem;font-weight:600;color:var(--primary);background:var(--primary-light);padding:.2rem .5rem;border-radius:4px;align-self:flex-start;margin-top:.25rem}

/* FOOTER */
.site-footer{background:var(--text);color:rgba(255,255,255,.7);padding:3rem 1.5rem 2rem;margin-top:4rem}
.footer-inner{max-width:var(--max-width);margin:0 auto}
.footer-grid{display:grid;grid-template-columns:2fr 1fr 1fr 1fr;gap:2.5rem;margin-bottom:2.5rem}
.footer-brand .logo{color:white;margin-bottom:.75rem;display:inline-flex}
.footer-brand p{font-size:.875rem;line-height:1.6}
.footer-col h4{color:white;font-size:.9rem;margin-bottom:.75rem}
.footer-col ul{list-style:none;padding:0}
.footer-col ul li{margin-bottom:.4rem}
.footer-col ul li a{font-size:.85rem;color:rgba(255,255,255,.65);text-decoration:none;transition:color .15s}
.footer-col ul li a:hover{color:white}
.footer-bottom{border-top:1px solid rgba(255,255,255,.1);padding-top:1.5rem;display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:.5rem;font-size:.82rem}

/* RESPONSIVE */
@media(max-width:900px){.page-layout{grid-template-columns:1fr}.footer-grid{grid-template-columns:1fr 1fr}h1{font-size:1.6rem}.hero h1{font-size:1.85rem}}
@media(max-width:600px){.header-nav{display:none}.input-row{grid-template-columns:1fr}.input-row.triple{grid-template-columns:1fr}.result-grid{grid-template-columns:1fr 1fr}.footer-grid{grid-template-columns:1fr}.hero-stats{gap:1.5rem}.hero h1{font-size:1.5rem}}
@media print{.site-header,.share-bar,.breadcrumb-bar,.sidebar,.site-footer{display:none}.page-layout{grid-template-columns:1fr}}