* { box-sizing: border-box; margin: 0; padding: 0; }
:root {
   --accent: #46e0a0;
   --accent-2: #5dedb4;
   --bg: #0b0d12;
   --card: #14181f;
   --line: #232a36;
   --text: #e6e6e6;
   --muted: #8a97a8;
}
body {
   font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
   background: var(--bg);
   color: var(--text);
   line-height: 1.5;
}
a { color: var(--accent); text-decoration: none; }
.wrap { width: 100%; max-width: 1080px; margin: 0 auto; padding: 0 20px; }

/* nav */
nav {
   display: flex; align-items: center; justify-content: space-between;
   padding: 18px 0;
}
.brand { display: flex; align-items: center; gap: 10px; font-weight: 800; font-size: 18px; }
.logo {
   width: 30px; height: 30px; border-radius: 8px;
   background: linear-gradient(135deg, var(--accent), #2b8fd6);
   display: grid; place-items: center; font-size: 18px;
}
.nav-links { display: flex; gap: 24px; align-items: center; font-size: 14px; color: var(--muted); }
.nav-links a { color: var(--muted); }
.nav-links a:hover { color: var(--text); }

button.btn {
   background: var(--accent); color: #062a1c; border: 0;
   border-radius: 10px; padding: 11px 20px; font-size: 14px;
   font-weight: 700; cursor: pointer; transition: 0.15s;
}
button.btn:hover { background: var(--accent-2); transform: translateY(-1px); }
button.btn:disabled { background: #333d4d; color: var(--muted); cursor: not-allowed; transform: none; }

/* hero */
.hero { text-align: center; padding: 60px 0 30px; }
.hero h1 { font-size: clamp(32px, 5vw, 52px); line-height: 1.08; letter-spacing: -1px; }
.hero h1 b { color: var(--accent); }
.hero p { color: var(--muted); font-size: 18px; max-width: 560px; margin: 18px auto 0; }
.trust-row { display: flex; gap: 22px; justify-content: center; flex-wrap: wrap; margin-top: 26px; font-size: 13px; color: var(--muted); }
.trust-row span { display: flex; align-items: center; gap: 6px; }

/* tool card */
.tool {
   background: var(--card); border: 1px solid var(--line);
   border-radius: 18px; padding: 34px 28px; margin: 10px auto 0;
   max-width: 620px; box-shadow: 0 24px 60px rgba(0,0,0,0.4);
}
.drop {
   border: 2px dashed #333d4d; border-radius: 16px;
   padding: 38px 20px; cursor: pointer; transition: 0.15s; text-align: center;
   user-select: none; background: #10141b;
}
.drop:hover, .drop.drag { background: #15202b; border-color: var(--accent); }
.drop-title { font-size: 18px; font-weight: 700; }
.drop-or { color: var(--muted); font-size: 13px; margin-top: 8px; }
.drop-sub { color: var(--muted); font-size: 12px; margin-top: 12px; }
.controls { margin-top: 20px; text-align: left; }
.controls.hidden { display: none; }
.field { margin-bottom: 14px; }
.field > label { font-size: 13px; color: var(--muted); margin-bottom: 6px; display: flex; justify-content: space-between; }
.field input[type=range], .field select {
   width: 100%; accent-color: var(--accent);
}
.field select {
   padding: 9px; background: #0e1117; color: var(--text);
   border: 1px solid var(--line); border-radius: 8px;
}
.field .hint { font-size: 11px; color: #6b7788; margin-top: 5px; }
.run-row { text-align: center; margin-top: 18px; }
.bar { height: 8px; background: #0e1117; border-radius: 6px; overflow: hidden; margin: 14px auto 0; max-width: 320px; display: none; }
.bar > i { display: block; height: 100%; width: 0; background: var(--accent); transition: width 0.1s; }

.result {
   margin-top: 20px; padding: 18px; background: #10141b;
   border: 1px solid var(--line); border-radius: 12px; text-align: left; display: none;
}
.result .row { display: flex; justify-content: space-between; font-size: 14px; margin: 7px 0; }
.result .row .v { color: #fff; font-weight: 600; }
.gain { color: var(--accent); font-weight: 800; }
.dl { display: inline-block; margin-top: 6px; color: var(--accent); font-weight: 700; }

.error { color: #ff7a7a; font-size: 13px; margin-top: 14px; display: none; text-align: center; }
.limit { font-size: 12px; color: var(--muted); margin-top: 16px; text-align: center; }
.log {
   display: none; margin-top: 12px; padding: 12px; background: #0e1117;
   border: 1px solid var(--line); border-radius: 10px; font-family: ui-monospace, Menlo, monospace;
   font-size: 11px; color: var(--muted); white-space: pre-wrap; max-height: 160px; overflow: auto;
}

/* ad slot */
.ad {
   max-width: 620px; margin: 22px auto 0; text-align: center;
   border: 1px dashed #2b3444; border-radius: 10px; padding: 14px;
   font-size: 12px; color: var(--muted); background: #10141b;
}
.ad b { color: #ffd479; }

/* how */
section.steps { padding: 50px 0; }
h2.sec { text-align: center; font-size: 26px; margin-bottom: 8px; }
.sec-sub { text-align: center; color: var(--muted); margin-bottom: 34px; font-size: 15px; }
.grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.step { background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 24px; }
.step .n { font-size: 13px; color: var(--accent); font-weight: 700; }
.step h3 { font-size: 17px; margin: 8px 0; }
.step p { color: var(--muted); font-size: 14px; }

/* security */
.badges { display: flex; gap: 18px; justify-content: center; flex-wrap: wrap; margin-top: 20px; }
.badge {
   border: 1px solid var(--line); border-radius: 10px; padding: 12px 18px;
   font-size: 13px; color: var(--muted); background: var(--card);
}
.badge b { color: var(--text); display: block; }

/* pricing */
.plans { display: grid; grid-template-columns: repeat(2, 1fr); gap: 18px; max-width: 620px; margin: 0 auto; }
.plan { background: var(--card); border: 1px solid var(--line); border-radius: 16px; padding: 26px; }
.plan.feat { border-color: var(--accent); position: relative; }
.plan .tag { position: absolute; top: -10px; left: 26px; background: var(--accent); color: #062a1c; font-size: 11px; font-weight: 700; padding: 2px 10px; border-radius: 20px; }
.plan h3 { font-size: 18px; }
.plan .price { font-size: 34px; font-weight: 800; margin: 10px 0; }
.plan .price small { font-size: 14px; color: var(--muted); font-weight: 400; }
.plan ul { list-style: none; margin: 14px 0; }
.plan li { color: var(--muted); font-size: 14px; margin: 8px 0; }
.plan li::before { content: "✓ "; color: var(--accent); font-weight: 700; }

/* multi-file merge UI */
.filelist { list-style: none; margin: 14px 0; text-align: left; }
.filelist li {
   display: flex; align-items: center; justify-content: space-between;
   gap: 10px; padding: 10px 12px; margin: 8px 0;
   background: #0e1117; border: 1px solid var(--line); border-radius: 10px;
   font-size: 13px;
}
.filelist .fname { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; max-width: 100%; }
.filelist .fsize { color: var(--muted); font-size: 12px; flex-shrink: 0; }
.filelist .fbtn { background: none; border: 0; color: #ff7a7a; cursor: pointer; font-size: 16px; flex-shrink: 0; }
.filelist .fbtn:hover { color: #ffb3b3; }
.tools-row { display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; margin-top: 14px; }
.tools-row .mini {
   background: #10141b; border: 1px solid var(--line); color: var(--muted);
   padding: 8px 14px; border-radius: 8px; font-size: 13px; cursor: pointer;
}
.tools-row .mini:hover { color: var(--text); border-color: var(--accent); }

/* footer */
footer { border-top: 1px solid var(--line); margin-top: 60px; padding: 30px 0 40px; }
.foot { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 20px; font-size: 13px; color: var(--muted); }

/* content + FAQ (SEO) */
.content { max-width: 760px; margin: 0 auto; padding: 10px 20px 0; }
.content h2 { font-size: 24px; margin: 36px 0 10px; }
.content h3 { font-size: 18px; margin: 22px 0 8px; color: var(--text); }
.content p { color: var(--muted); font-size: 15px; margin: 10px 0; }
.content ul { color: var(--muted); font-size: 15px; margin: 10px 0 10px 20px; }
.content li { margin: 6px 0; }
.content a { color: var(--accent); }

.faq { max-width: 760px; margin: 0 auto; padding: 36px 20px 0; }
.faq h2 { font-size: 24px; margin-bottom: 18px; }
.faq details {
   border: 1px solid var(--line); border-radius: 12px; margin: 10px 0;
   background: var(--card); padding: 14px 18px;
}
.faq summary { cursor: pointer; font-weight: 600; font-size: 15px; list-style: none; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; float: right; color: var(--accent); }
.faq details[open] summary::after { content: "−"; }
.faq p { color: var(--muted); font-size: 14px; margin: 10px 0 0; }

.related {
   max-width: 760px; margin: 40px auto 0; padding: 0 20px;
   text-align: center;
}
.related h3 { color: var(--text); font-size: 16px; margin-bottom: 12px; }
.related .tools-row { justify-content: center; }

@media (max-width: 720px) {
   .grid, .plans { grid-template-columns: 1fr; }
   .nav-links { display: none; }
}