:root {
  --bg: #0f172a;
  --bg-soft: #1e293b;
  --card: #ffffff;
  --text: #0f172a;
  --muted: #64748b;
  --brand: #6366f1;
  --brand-dark: #4f46e5;
  --ok: #16a34a;
  --err: #dc2626;
  --radius: 14px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  color: var(--text);
  background: radial-gradient(1200px 600px at 50% -10%, #312e81 0%, var(--bg) 55%);
  display: flex;
  justify-content: center;
  padding: 6vh 16px;
}

.wrap { width: 100%; max-width: 560px; }

.hero { text-align: center; color: #e2e8f0; margin-bottom: 28px; }

.logo {
  font-size: 26px;
  font-weight: 800;
  letter-spacing: -0.5px;
  color: #fff;
}
.logo span { color: var(--brand); }

.hero h1 {
  font-size: clamp(28px, 6vw, 40px);
  margin: 18px 0 8px;
  color: #fff;
}
.sub { color: #94a3b8; margin: 0; }

.card {
  background: var(--card);
  border-radius: var(--radius);
  padding: 22px;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.35);
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.field { display: flex; flex-direction: column; gap: 6px; }
.field > span { font-size: 14px; font-weight: 600; color: #334155; }
.field small { color: var(--muted); font-size: 12px; }

input[type="url"],
input[type="text"] {
  width: 100%;
  padding: 13px 14px;
  border: 1px solid #e2e8f0;
  border-radius: 10px;
  font-size: 15px;
  outline: none;
  transition: border-color .15s, box-shadow .15s;
}
input:focus {
  border-color: var(--brand);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.15);
}

.advanced summary {
  cursor: pointer;
  font-size: 14px;
  color: var(--brand-dark);
  font-weight: 600;
  user-select: none;
}
.advanced[open] { display: flex; flex-direction: column; gap: 10px; }
.advanced .field { margin-top: 10px; }

button {
  border: none;
  border-radius: 10px;
  font-size: 15px;
  font-weight: 700;
  cursor: pointer;
  padding: 13px 16px;
  transition: transform .05s, background .15s;
}
button:active { transform: translateY(1px); }

#submit {
  background: var(--brand);
  color: #fff;
}
#submit:hover { background: var(--brand-dark); }
#submit:disabled { opacity: .6; cursor: default; }

.result {
  margin-top: 18px;
  background: var(--card);
  border-radius: var(--radius);
  padding: 18px;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.25);
}
.result-row { display: flex; gap: 8px; }
.result-row input {
  flex: 1;
  font-weight: 600;
  color: var(--brand-dark);
}
#copy { background: #eef2ff; color: var(--brand-dark); white-space: nowrap; }
#copy:hover { background: #e0e7ff; }
#copy.copied { background: var(--ok); color: #fff; }

.result-meta {
  margin: 12px 0 0;
  font-size: 13px;
  color: var(--muted);
  word-break: break-all;
}
.result-meta a { color: var(--brand-dark); font-weight: 600; }

.error {
  margin-top: 16px;
  background: #fef2f2;
  color: var(--err);
  padding: 12px 14px;
  border-radius: 10px;
  font-size: 14px;
  text-align: center;
}

.foot {
  text-align: center;
  color: #64748b;
  font-size: 13px;
  margin-top: 28px;
}

.hidden { display: none; }