/* ===================================================================
   T4UHubPDF — Mobile-app design system
   =================================================================== */
:root{
  --primary:#2563EB; --secondary:#1E40AF; --accent:#3B82F6;
  --success:#10B981; --warning:#F59E0B; --danger:#EF4444;
  --bg:#F8FAFC; --card:#FFFFFF; --text:#111827; --muted:#6B7280;
  --border:#E5E7EB; --shadow:0 1px 2px rgba(16,24,40,.06),0 4px 16px rgba(16,24,40,.06);
  --shadow-lg:0 8px 30px rgba(37,99,235,.18);
  --radius:18px; --radius-sm:12px; --nav-h:64px; --header-h:60px;
  --grad:linear-gradient(135deg,#2563EB 0%,#3B82F6 60%,#1E40AF 100%);
  --safe-b:env(safe-area-inset-bottom,0px);
  --ease:cubic-bezier(.22,1,.36,1);
}
[data-theme="dark"]{
  --bg:#0B1220; --card:#131C2E; --text:#E5EAF2; --muted:#94A3B8;
  --border:#243049; --shadow:0 1px 2px rgba(0,0,0,.4),0 6px 20px rgba(0,0,0,.35);
  --shadow-lg:0 10px 34px rgba(0,0,0,.55);
}
*{box-sizing:border-box;-webkit-tap-highlight-color:transparent}
html{scroll-behavior:smooth}
body{
  margin:0;font-family:"Inter",system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;
  background:var(--bg);color:var(--text);line-height:1.6;
  padding-bottom:calc(var(--nav-h) + var(--safe-b) + 8px);
  overflow-x:hidden;-webkit-font-smoothing:antialiased;transition:background .3s var(--ease),color .3s var(--ease);
}
a{color:var(--primary);text-decoration:none}
img{max-width:100%}
.container{width:100%;max-width:1080px;margin:0 auto;padding:0 16px}
.hidden{display:none!important}

/* ---------- Top header ---------- */
.app-header{
  position:sticky;top:0;z-index:40;height:var(--header-h);
  display:flex;align-items:center;justify-content:space-between;gap:10px;
  padding:0 16px;background:color-mix(in srgb,var(--card) 86%,transparent);
  backdrop-filter:saturate(180%) blur(14px);border-bottom:1px solid var(--border);
}
.brand{display:flex;align-items:center;gap:9px;font-weight:800;font-size:18px;letter-spacing:-.02em;color:var(--text)}
.brand .logo{width:30px;height:30px;border-radius:9px;background:var(--grad);display:grid;place-items:center;color:#fff;font-size:14px;box-shadow:var(--shadow-lg)}
.brand b{color:var(--primary)}
.header-actions{display:flex;align-items:center;gap:6px}
.icon-btn{width:40px;height:40px;border:none;background:transparent;color:var(--text);border-radius:12px;display:grid;place-items:center;cursor:pointer;font-size:19px;transition:background .2s}
.icon-btn:active{background:color-mix(in srgb,var(--primary) 12%,transparent)}

/* ---------- Hero ---------- */
.hero{position:relative;padding:30px 0 26px;background:var(--grad);color:#fff;overflow:hidden;border-radius:0 0 26px 26px}
.hero::after{content:"";position:absolute;inset:0;background:radial-gradient(420px 220px at 85% -20%,rgba(255,255,255,.25),transparent)}
.hero .container{position:relative;z-index:1}
.hero h1{margin:0 0 6px;font-size:26px;line-height:1.2;letter-spacing:-.03em;font-weight:800}
.hero p{margin:0 0 16px;opacity:.92;font-size:14.5px;max-width:560px}
.searchbar{display:flex;align-items:center;gap:10px;background:#fff;border-radius:14px;padding:12px 14px;box-shadow:var(--shadow-lg)}
.searchbar input{border:none;outline:none;flex:1;font-size:15px;background:transparent;color:#111827}
.hero-stats{display:flex;gap:18px;margin-top:14px;font-size:13px;opacity:.95}
.hero-stats b{display:block;font-size:18px;font-weight:800}

/* ---------- Sections ---------- */
section{padding:22px 0}
.section-head{display:flex;align-items:center;justify-content:space-between;margin-bottom:14px}
.section-head h2{font-size:18px;margin:0;letter-spacing:-.02em}
.section-head a{font-size:13px;font-weight:600}

/* ---------- Category chips (horizontal scroll) ---------- */
.chips{display:flex;gap:10px;overflow-x:auto;padding:2px 2px 8px;scrollbar-width:none;scroll-snap-type:x mandatory}
.chips::-webkit-scrollbar{display:none}
.chip{flex:0 0 auto;scroll-snap-align:start;display:flex;align-items:center;gap:8px;background:var(--card);border:1px solid var(--border);padding:10px 14px;border-radius:999px;font-size:13.5px;font-weight:600;color:var(--text);box-shadow:var(--shadow);transition:transform .15s var(--ease)}
.chip:active{transform:scale(.96)}
.chip .dot{width:9px;height:9px;border-radius:50%}

/* ---------- Tool grid ---------- */
.grid{display:grid;grid-template-columns:repeat(2,1fr);gap:12px}
@media(min-width:640px){.grid{grid-template-columns:repeat(3,1fr)}}
@media(min-width:900px){.grid{grid-template-columns:repeat(4,1fr)}}
.tool-card{position:relative;background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:14px;box-shadow:var(--shadow);display:flex;flex-direction:column;gap:9px;transition:transform .18s var(--ease),box-shadow .18s var(--ease);animation:rise .5s var(--ease) both}
.tool-card:active{transform:scale(.97)}
@media(hover:hover){.tool-card:hover{transform:translateY(-3px);box-shadow:var(--shadow-lg)}}
.tool-ic{width:42px;height:42px;border-radius:12px;display:grid;place-items:center;font-size:20px;color:#fff;flex:0 0 auto}
.tool-card h3{margin:0;font-size:14px;font-weight:700;letter-spacing:-.01em;line-height:1.3}
.tool-card p{margin:0;font-size:12px;color:var(--muted);line-height:1.45}
.badge{position:absolute;top:10px;right:10px;font-size:9.5px;font-weight:800;letter-spacing:.04em;padding:3px 7px;border-radius:999px;text-transform:uppercase}
.badge.live{background:color-mix(in srgb,var(--success) 16%,transparent);color:var(--success)}
.badge.soon{background:color-mix(in srgb,var(--warning) 18%,transparent);color:var(--warning)}

/* ---------- Category cards (big) ---------- */
.cat-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:12px}
.cat-card{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:16px;box-shadow:var(--shadow);display:flex;flex-direction:column;gap:8px;transition:transform .18s var(--ease)}
.cat-card:active{transform:scale(.97)}
.cat-card .tool-ic{width:46px;height:46px}
.cat-card h3{margin:0;font-size:15px}
.cat-card span{font-size:12px;color:var(--muted)}

/* ---------- Bottom nav ---------- */
.bottom-nav{
  position:fixed;left:0;right:0;bottom:0;z-index:50;height:calc(var(--nav-h) + var(--safe-b));
  padding-bottom:var(--safe-b);display:flex;justify-content:space-around;align-items:stretch;
  background:color-mix(in srgb,var(--card) 92%,transparent);backdrop-filter:saturate(180%) blur(16px);
  border-top:1px solid var(--border);
}
.bottom-nav a{flex:1;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:3px;font-size:10.5px;font-weight:600;color:var(--muted);transition:color .2s}
.bottom-nav a .ni{font-size:20px;line-height:1;transition:transform .2s var(--ease)}
.bottom-nav a.active{color:var(--primary)}
.bottom-nav a.active .ni{transform:translateY(-2px) scale(1.08)}

/* ---------- Floating Upload Button ---------- */
.fab{
  position:fixed;right:18px;bottom:calc(var(--nav-h) + var(--safe-b) + 16px);z-index:55;
  width:58px;height:58px;border-radius:50%;border:none;background:var(--grad);color:#fff;
  font-size:26px;display:grid;place-items:center;cursor:pointer;box-shadow:var(--shadow-lg);
  animation:pulse 2.6s infinite;transition:transform .2s var(--ease)
}
.fab:active{transform:scale(.9)}

/* ---------- Install banner ---------- */
.install-banner{position:fixed;left:12px;right:12px;bottom:calc(var(--nav-h) + var(--safe-b) + 84px);z-index:56;background:var(--card);border:1px solid var(--border);border-radius:16px;padding:12px 14px;box-shadow:var(--shadow-lg);display:flex;align-items:center;gap:12px;transform:translateY(140%);transition:transform .4s var(--ease)}
.install-banner.show{transform:translateY(0)}
.install-banner .ib-ic{width:40px;height:40px;border-radius:11px;background:var(--grad);display:grid;place-items:center;color:#fff;font-size:18px;flex:0 0 auto}
.install-banner strong{font-size:13.5px;display:block}
.install-banner small{font-size:11.5px;color:var(--muted)}
.btn{appearance:none;border:none;cursor:pointer;font-weight:700;border-radius:12px;padding:10px 16px;font-size:13.5px;transition:transform .15s var(--ease),box-shadow .2s}
.btn-primary{background:var(--grad);color:#fff;box-shadow:var(--shadow-lg)}
.btn-primary:active{transform:scale(.96)}
.btn-ghost{background:transparent;color:var(--muted)}
.btn-block{width:100%;display:flex;align-items:center;justify-content:center;gap:8px}

/* ---------- Tool workspace ---------- */
.breadcrumb{font-size:12px;color:var(--muted);padding:12px 0 0}
.breadcrumb a{color:var(--muted)}
.tool-hero{display:flex;gap:14px;align-items:center;padding:14px 0 6px}
.tool-hero .tool-ic{width:54px;height:54px;font-size:26px}
.tool-hero h1{margin:0;font-size:21px;letter-spacing:-.02em}
.tool-hero p{margin:2px 0 0;font-size:13px;color:var(--muted)}
.dropzone{margin-top:14px;border:2px dashed color-mix(in srgb,var(--primary) 40%,var(--border));border-radius:var(--radius);background:color-mix(in srgb,var(--primary) 5%,var(--card));padding:34px 18px;text-align:center;transition:.2s var(--ease);cursor:pointer}
.dropzone.drag{border-color:var(--primary);background:color-mix(in srgb,var(--primary) 12%,var(--card));transform:scale(1.01)}
.dropzone .dz-ic{font-size:40px}
.dropzone h3{margin:8px 0 3px;font-size:16px}
.dropzone p{margin:0;font-size:12.5px;color:var(--muted)}
.file-list{display:flex;flex-direction:column;gap:8px;margin-top:14px}
.file-item{display:flex;align-items:center;gap:11px;background:var(--card);border:1px solid var(--border);border-radius:14px;padding:10px 12px;box-shadow:var(--shadow);animation:rise .35s var(--ease) both}
.file-item .fi-ic{width:34px;height:34px;border-radius:9px;background:color-mix(in srgb,var(--danger) 14%,transparent);color:var(--danger);display:grid;place-items:center;font-size:15px;flex:0 0 auto}
.file-item .fi-meta{flex:1;min-width:0}
.file-item .fi-meta b{font-size:13px;font-weight:600;display:block;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.file-item .fi-meta small{font-size:11px;color:var(--muted)}
.file-item .fi-x{border:none;background:transparent;color:var(--muted);font-size:18px;cursor:pointer;padding:4px}
.field{margin-top:14px}
.field label{display:block;font-size:12.5px;font-weight:600;margin-bottom:6px}
.field input,.field select,.field textarea{width:100%;padding:11px 12px;border:1px solid var(--border);border-radius:12px;background:var(--card);color:var(--text);font-size:14px;outline:none;transition:border .2s}
.field input:focus,.field select:focus{border-color:var(--primary)}
.toolbar-actions{display:flex;gap:10px;margin-top:16px}
.progress{height:8px;background:var(--border);border-radius:999px;overflow:hidden;margin-top:14px}
.progress>i{display:block;height:100%;width:0;background:var(--grad);transition:width .3s var(--ease)}
.result{margin-top:14px;background:color-mix(in srgb,var(--success) 8%,var(--card));border:1px solid color-mix(in srgb,var(--success) 30%,var(--border));border-radius:14px;padding:14px;text-align:center}
.result .r-ic{font-size:32px}
.note{margin-top:12px;font-size:12px;color:var(--muted);background:color-mix(in srgb,var(--warning) 8%,var(--card));border:1px solid color-mix(in srgb,var(--warning) 26%,var(--border));border-radius:12px;padding:10px 12px}

/* ---------- SEO content / article ---------- */
.prose{padding:8px 0 4px}
.prose h2{font-size:19px;margin:22px 0 8px;letter-spacing:-.02em}
.prose h3{font-size:16px;margin:18px 0 6px}
.prose p{font-size:14.5px;color:var(--text)}
.prose ul{padding-left:20px}
.prose li{font-size:14.5px;margin:5px 0}
.faq{margin-top:10px}
.faq details{background:var(--card);border:1px solid var(--border);border-radius:14px;padding:4px 14px;margin-bottom:10px;box-shadow:var(--shadow)}
.faq summary{cursor:pointer;font-weight:700;font-size:14px;padding:11px 0;list-style:none}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"+";float:right;color:var(--primary);font-weight:800}
.faq details[open] summary::after{content:"–"}
.faq p{margin:0 0 12px;font-size:13.5px;color:var(--muted)}

/* ---------- Footer ---------- */
.footer{background:var(--card);border-top:1px solid var(--border);margin-top:24px;padding:26px 0 20px}
.footer-cols{display:grid;grid-template-columns:repeat(2,1fr);gap:18px}
@media(min-width:720px){.footer-cols{grid-template-columns:repeat(4,1fr)}}
.footer h4{font-size:13px;margin:0 0 10px;letter-spacing:-.01em}
.footer a{display:block;font-size:12.5px;color:var(--muted);padding:4px 0}
.newsletter{display:flex;gap:8px;margin-top:8px}
.newsletter input{flex:1;padding:10px;border:1px solid var(--border);border-radius:10px;background:var(--bg);color:var(--text);font-size:13px}
.footer-bottom{border-top:1px solid var(--border);margin-top:18px;padding-top:16px;font-size:12px;color:var(--muted);text-align:center}
.ad-slot{margin:16px 0;background:repeating-linear-gradient(45deg,color-mix(in srgb,var(--border) 50%,transparent),color-mix(in srgb,var(--border) 50%,transparent) 10px,transparent 10px,transparent 20px);border:1px dashed var(--border);border-radius:14px;min-height:90px;display:grid;place-items:center;color:var(--muted);font-size:11px;letter-spacing:.08em;text-transform:uppercase}

/* ---------- Animations ---------- */
@keyframes rise{from{opacity:0;transform:translateY(10px)}to{opacity:1;transform:none}}
@keyframes pulse{0%,100%{box-shadow:0 8px 30px rgba(37,99,235,.4)}50%{box-shadow:0 8px 40px rgba(37,99,235,.7)}}
.reveal{opacity:0;transform:translateY(14px)}
.reveal.in{opacity:1;transform:none;transition:opacity .5s var(--ease),transform .5s var(--ease)}
@media(prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important}}

/* ---------- Search overlay ---------- */
.search-overlay{position:fixed;inset:0;z-index:70;background:var(--bg);transform:translateY(100%);transition:transform .35s var(--ease);display:flex;flex-direction:column}
.search-overlay.show{transform:none}
.search-overlay .so-head{display:flex;gap:10px;align-items:center;padding:14px 16px;border-bottom:1px solid var(--border)}
.search-overlay input{flex:1;border:none;background:transparent;font-size:17px;outline:none;color:var(--text)}
.search-results{flex:1;overflow-y:auto;padding:8px 16px 90px}
.sr-item{display:flex;align-items:center;gap:12px;padding:12px 6px;border-bottom:1px solid var(--border)}
.sr-item .tool-ic{width:38px;height:38px;font-size:17px}
.sr-item b{font-size:14px;font-weight:600}
.sr-item small{display:block;font-size:11.5px;color:var(--muted)}