:root{
  --bg:#000000;--bg-secondary:#0a0a0a;--bg-card:#111111;--bg-elevated:#171717;
  --text-primary:#ededed;--text-secondary:#888888;--text-tertiary:#666666;
  --border:rgba(255,255,255,0.08);--border-hover:rgba(255,255,255,0.15);
  --accent:#0070f3;--accent-hover:#0060df;
  --success:#0cce6b;--warning:#f5a623;--danger:#ee0000;
  --font-sans:'Inter',-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,sans-serif;
  --font-mono:'JetBrains Mono',ui-monospace,SFMono-Regular,Menlo,monospace;
  --radius-sm:6px;--radius-md:8px;--radius-lg:12px;--radius-xl:16px;--radius-full:9999px;
  --shadow-sm:0 0 0 1px var(--border),0 2px 4px rgba(0,0,0,0.3);
  --shadow-md:0 0 0 1px var(--border),0 4px 8px rgba(0,0,0,0.4);
  --shadow-lg:0 0 0 1px var(--border),0 8px 16px rgba(0,0,0,0.5);
  --shadow-focus:0 0 0 2px var(--bg),0 0 0 4px var(--accent);
  --t-fast:150ms ease;--t-base:200ms ease;
}
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{font-size:16px;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;scroll-behavior:smooth}
body{font-family:var(--font-sans);background:var(--bg);color:var(--text-primary);line-height:1.6;min-height:100vh;
  background-image:radial-gradient(ellipse 80% 50% at 50% -20%,rgba(0,112,243,0.10),transparent),
                   radial-gradient(rgba(255,255,255,0.035) 1px,transparent 1px);
  background-size:100% 100%,26px 26px;background-attachment:fixed}
a{color:var(--accent);text-decoration:none;transition:color var(--t-fast)}
a:hover{color:var(--accent-hover)}
img{max-width:100%;height:auto;display:block}
::selection{background:rgba(0,112,243,0.35)}

.container{max-width:760px;margin:0 auto;padding:0 20px}

/* NAV */
.nav{position:sticky;top:0;z-index:100;height:60px;display:flex;align-items:center;
  background:rgba(0,0,0,0.72);backdrop-filter:blur(14px);-webkit-backdrop-filter:blur(14px);
  border-bottom:1px solid var(--border)}
.nav-inner{max-width:1100px;margin:0 auto;padding:0 20px;width:100%;display:flex;align-items:center;justify-content:space-between}
.nav-brand{display:flex;align-items:center;gap:10px;font-weight:600;font-size:15px;color:var(--text-primary)}
.nav-logo{width:30px;height:30px;display:flex;align-items:center;justify-content:center;flex-shrink:0}
.nav-logo svg{width:100%;height:100%;display:block}

/* HERO */
.hero{padding:56px 0 28px;text-align:center}
.hero h1{font-size:clamp(28px,6vw,44px);font-weight:700;letter-spacing:-0.035em;line-height:1.12;margin-bottom:14px}
.hero h1 .grad{background:linear-gradient(100deg,#0070f3,#00c6ff 55%,#7c3aed);-webkit-background-clip:text;
  background-clip:text;-webkit-text-fill-color:transparent}
.hero p{font-size:16px;color:var(--text-secondary);max-width:520px;margin:0 auto}

/* CARD */
.card{background:var(--bg-card);border-radius:var(--radius-xl);box-shadow:var(--shadow-sm);padding:22px;
  transition:box-shadow var(--t-base)}
.card:hover{box-shadow:var(--shadow-md)}
.main-card{margin-top:28px;padding:24px}

/* TABS */
.tabs{display:flex;gap:4px;padding:4px;background:var(--bg);border-radius:var(--radius-lg);
  box-shadow:0 0 0 1px var(--border);margin-bottom:20px}
.tab{flex:1;display:flex;align-items:center;justify-content:center;gap:8px;height:42px;border-radius:var(--radius-md);
  border:none;background:transparent;color:var(--text-secondary);font:500 14px var(--font-sans);cursor:pointer;
  transition:all var(--t-fast);-webkit-tap-highlight-color:transparent}
.tab:hover{color:var(--text-primary)}
.tab.active{background:var(--bg-elevated);color:var(--text-primary);box-shadow:0 1px 3px rgba(0,0,0,0.4)}
.tab svg{width:16px;height:16px}

/* FORM */
.field{display:flex;flex-direction:column;gap:8px}
.input-wrap{position:relative;display:flex;align-items:center}
.input{width:100%;height:50px;padding:0 15px 0 44px;background:var(--bg);border:1px solid var(--border);
  border-radius:var(--radius-lg);color:var(--text-primary);font:15px var(--font-sans);transition:border-color var(--t-fast)}
.input:focus{outline:none;border-color:var(--accent);box-shadow:0 0 0 3px rgba(0,112,243,0.15)}
.input::placeholder{color:var(--text-tertiary)}
.input-icon{position:absolute;left:15px;color:var(--text-tertiary);pointer-events:none;display:flex}
.input-icon svg{width:18px;height:18px}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;height:50px;padding:0 22px;border-radius:var(--radius-lg);
  font:600 15px var(--font-sans);cursor:pointer;border:1px solid transparent;transition:all var(--t-fast);
  -webkit-tap-highlight-color:transparent}
.btn-primary{background:var(--text-primary);color:var(--bg)}
.btn-primary:hover:not(:disabled){background:#cfcfcf}
.btn-primary:disabled{opacity:0.45;cursor:not-allowed}
.btn-block{width:100%;margin-top:14px}
.btn:focus-visible{outline:none;box-shadow:var(--shadow-focus)}
.spinner{width:17px;height:17px;border:2px solid rgba(0,0,0,0.25);border-top-color:var(--bg);border-radius:50%;
  animation:spin .6s linear infinite}
@keyframes spin{to{transform:rotate(360deg)}}
.hint{font-size:12.5px;color:var(--text-tertiary);margin-top:10px;text-align:center}

/* ALERT */
.alert{display:none;gap:10px;align-items:flex-start;padding:13px 15px;border-radius:var(--radius-lg);font-size:13.5px;
  margin-top:16px;animation:slidein .2s ease}
.alert.show{display:flex}
.alert-error{background:rgba(238,0,0,0.08);box-shadow:0 0 0 1px rgba(238,0,0,0.28);color:#ff8080}
@keyframes slidein{from{opacity:0;transform:translateY(-6px)}to{opacity:1;transform:translateY(0)}}

/* RESULT */
.result{display:none;margin-top:18px;padding:16px;border-radius:var(--radius-xl);background:var(--bg-secondary);
  box-shadow:0 0 0 1px var(--border);animation:fade .3s ease}
.result.show{display:block}
@keyframes fade{from{opacity:0;transform:translateY(8px)}to{opacity:1;transform:translateY(0)}}
.vid{display:flex;gap:13px;align-items:center}
.thumb{width:96px;height:54px;border-radius:var(--radius-md);object-fit:cover;background:var(--bg-elevated);flex-shrink:0}
.vid-meta{min-width:0;flex:1}
.vid-title{font-size:14.5px;font-weight:600;line-height:1.35;margin-bottom:4px;
  display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.vid-sub{font-size:12.5px;color:var(--text-tertiary);display:flex;gap:8px;flex-wrap:wrap}
.sep{opacity:0.4}

.progress{height:4px;border-radius:var(--radius-full);background:var(--bg-elevated);overflow:hidden;margin-top:16px}
.progress-bar{height:100%;width:35%;border-radius:var(--radius-full);
  background:linear-gradient(90deg,#0070f3,#00c6ff);animation:slide 1.3s ease-in-out infinite}
@keyframes slide{0%{margin-left:-35%}100%{margin-left:100%}}
.status-line{display:flex;align-items:center;gap:9px;font-size:13.5px;color:var(--text-secondary)}
.pulse{width:8px;height:8px;border-radius:50%;background:var(--accent);animation:pulse 1.2s infinite}
@keyframes pulse{0%,100%{opacity:1;transform:scale(1)}50%{opacity:0.35;transform:scale(0.8)}}

.dl-btn{background:var(--success);color:#000;margin-top:16px;font-weight:700}
.dl-btn:hover{background:#0bb95f}
.actions{display:flex;gap:10px;flex-wrap:wrap}
.actions .btn{flex:1;min-width:140px}
.btn-ghost{background:transparent;color:var(--text-secondary);border:1px solid var(--border)}
.btn-ghost:hover{background:var(--bg-elevated);color:var(--text-primary)}
.file-size{font-size:12.5px;color:var(--text-tertiary);margin-top:9px;text-align:center}

/* STEPS */
.steps{display:grid;grid-template-columns:repeat(3,1fr);gap:14px;margin-top:44px}
.step{padding:18px;border-radius:var(--radius-xl);background:var(--bg-card);box-shadow:var(--shadow-sm)}
.step-num{width:26px;height:26px;border-radius:var(--radius-md);background:rgba(0,112,243,0.12);color:var(--accent);
  display:flex;align-items:center;justify-content:center;font:600 13px var(--font-mono);margin-bottom:11px}
.step h4{font-size:14px;font-weight:600;margin-bottom:5px}
.step p{font-size:13px;color:var(--text-secondary);line-height:1.5}

/* FOOTER */
footer{border-top:1px solid var(--border);margin-top:56px;padding:30px 0}
.foot-inner{display:flex;justify-content:space-between;align-items:center;gap:16px;flex-wrap:wrap;font-size:13px;color:var(--text-tertiary)}
.foot-links{display:flex;gap:18px;flex-wrap:wrap}
.foot-links a{color:var(--text-tertiary);font-size:13px}
.foot-links a:hover{color:var(--text-primary)}

@media(max-width:640px){
  .hero{padding:40px 0 20px}
  .main-card{padding:18px}
  .steps{grid-template-columns:1fr}
  .tab span{display:none}
  .tab{gap:0}
  .tab svg{width:19px;height:19px}
  .thumb{width:76px;height:43px}
  .actions .btn{min-width:100%}
}