:root {
    --primary-dark: #1e293b; 
    --primary-blue: #2563eb; 
    --bg-light: #f8fafc;     
    --card-bg: #ffffff;
    --text-main: #334155;
    --border-color: #e2e8f0;
}
* { box-sizing: border-box; margin: 0; padding: 0; font-family: 'Segoe UI', sans-serif; }
body { background-color: var(--bg-light); color: var(--text-main); line-height: 1.6; display: flex; flex-direction: column; align-items: center; min-height: 100vh; }
nav { width: 100%; max-width: 1200px; display: flex; justify-content: space-between; align-items: center; padding: 20px; }
.logo { font-weight: bold; font-size: 1.2rem; color: var(--primary-dark); }
.nav-actions button { background: transparent; border: 1px solid var(--border-color); padding: 8px 16px; border-radius: 6px; cursor: pointer; font-weight: 600; color: var(--primary-dark); margin-left: 10px; transition: 0.2s; }
.nav-actions button:hover { background: var(--border-color); }
main { flex: 1; width: 100%; max-width: 800px; padding: 40px 20px; text-align: center; }
.hero h1 { font-size: 2.5rem; color: var(--primary-dark); margin-bottom: 15px; }
.hero p { font-size: 1.1rem; color: #64748b; margin-bottom: 40px; }
.tool-container { background: var(--card-bg); padding: 30px; border-radius: 12px; box-shadow: 0 10px 25px rgba(0,0,0,0.05); }
.input-group { display: flex; gap: 10px; margin-bottom: 20px; }
.input-group input { flex: 1; padding: 15px; border: 2px solid var(--border-color); border-radius: 8px; font-size: 1rem; outline: none; transition: border 0.3s; }
.input-group input:focus { border-color: var(--primary-blue); }
.input-group button { padding: 15px 30px; background: var(--primary-blue); color: white; border: none; border-radius: 8px; font-size: 1rem; font-weight: bold; cursor: pointer; transition: background 0.3s; }
.input-group button:hover { background: var(--primary-dark); }
#resultBox { margin-top: 30px; padding-top: 30px; border-top: 1px solid var(--border-color); animation: fadeIn 0.5s ease-in-out; }
.short-link-display { display: flex; gap: 10px; margin: 15px 0; justify-content: center; }
.short-link-display input { width: 60%; padding: 10px; border: 1px solid var(--border-color); background: var(--bg-light); border-radius: 6px; text-align: center; font-weight: bold; color: var(--primary-blue); }
.short-link-display button { padding: 10px 20px; background: var(--primary-dark); color: white; border: none; border-radius: 6px; cursor: pointer; }
#qrcodeDisplay img { margin: 0 auto; border: 10px solid white; border-radius: 8px; box-shadow: 0 4px 6px rgba(0,0,0,0.1); }
footer { width: 100%; text-align: center; padding: 20px; font-size: 0.9rem; color: #94a3b8; }
footer a { color: var(--primary-blue); text-decoration: none; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(-10px); } to { opacity: 1; transform: translateY(0); } }
@media (max-width: 600px) { .input-group { flex-direction: column; } .short-link-display { flex-direction: column; align-items: center; } .short-link-display input { width: 100%; } }