:root {
    --primary: #4f46e5;
    --brand-gradient: linear-gradient(135deg, #6366f1 0%, #a855f7 100%);
    --bg-body: #f8fafc;
    --bg-card: rgba(255, 255, 255, 0.98);
    --text-main: #0f172a;
    --text-muted: #64748b;
    --border: #e2e8f0;
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg-body: #020617;
        --bg-card: rgba(15, 23, 42, 0.95);
        --text-main: #f1f5f9;
        --text-muted: #94a3b8;
        --border: #1e293b;
    }
}

* { margin: 0; padding: 0; box-sizing: border-box; }

body {
    font-family: 'Plus Jakarta Sans', sans-serif;
    background-color: var(--bg-body);
    color: var(--text-main);
    padding: 60px 20px;
    line-height: 1.6;
}

.bg-blur-circle {
    position: fixed; top: -15%; right: -10%;
    width: 450px; height: 450px;
    background: var(--brand-gradient);
    filter: blur(140px); opacity: 0.1; z-index: -1;
}

.container { max-width: 900px; margin: 0 auto; }

/* Animaciones */
.animate-fade-in { animation: fadeIn 1s ease-out; }
.animate-slide-up { animation: slideUp 0.8s ease-out; }
@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }
@keyframes slideUp { from { opacity: 0; transform: translateY(30px); } to { opacity: 1; transform: translateY(0); } }

/* Header */
.main-header { text-align: center; margin-bottom: 4rem; }
.badge { background: var(--brand-gradient); color: white; padding: 6px 16px; border-radius: 50px; font-size: 0.75rem; font-weight: 800; margin-bottom: 1.5rem; display: inline-block; box-shadow: 0 4px 12px rgba(99, 102, 241, 0.2); }
.main-header h1 { font-size: 4rem; font-weight: 800; letter-spacing: -3px; line-height: 1; }
.main-header h1 span { background: var(--brand-gradient); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }

/* Card Principal */
.generator-card {
    background: var(--bg-card);
    backdrop-filter: blur(10px);
    padding: 3.5rem;
    border-radius: 32px;
    box-shadow: 0 25px 50px -12px rgba(0,0,0,0.15);
    border: 1px solid var(--border);
    margin-bottom: 5rem;
}

.input-wrapper input {
    width: 100%; padding: 20px; border-radius: 16px; border: 2px solid var(--border);
    background: var(--bg-body); color: var(--text-main); font-size: 1.1rem; transition: 0.3s;
}

.btn-primary {
    width: 100%; padding: 20px; background: var(--brand-gradient); color: white;
    border: none; border-radius: 16px; font-weight: 800; font-size: 1.1rem; cursor: pointer; margin-top: 2rem; transition: 0.3s;
}
.btn-primary:hover { transform: translateY(-3px); box-shadow: 0 15px 30px rgba(99, 102, 241, 0.3); }

/* Progress */
.progress-container { text-align: center; margin-top: 1.5rem; }
.progress-bar { background: var(--border); height: 10px; border-radius: 10px; overflow: hidden; margin-top: 10px; }
.progress-fill { background: var(--brand-gradient); height: 100%; width: 0; transition: width 0.1s linear; }

/* QR Result */
.qr-preview-area {
    margin-top: 3rem; padding: 3rem; background: rgba(100, 116, 139, 0.03);
    border-radius: 28px; border: 2px dashed var(--border); display: flex; flex-direction: column; align-items: center;
}
#qrcode img, #qrcode canvas { border: 12px solid white; border-radius: 12px; box-shadow: 0 10px 20px rgba(0,0,0,0.1); max-width: 100%; height: auto; }

/* Download Buttons */
.download-group { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; margin-top: 2.5rem; width: 100%; }
.btn-download {
    padding: 16px; border-radius: 16px; border: none; cursor: pointer;
    display: flex; flex-direction: column; align-items: center; transition: 0.3s; color: white;
}
.btn-download.png { background: #10b981; }
.btn-download.svg { background: #0ea5e9; }
.btn-download:hover { transform: scale(1.03); filter: brightness(1.1); }
.btn-download span { font-weight: 800; font-size: 1rem; }
.btn-download small { font-size: 0.7rem; opacity: 0.8; }

/* Casos de Uso */
.section-title { text-align: center; font-size: 2.2rem; margin-bottom: 3rem; font-weight: 800; }
.use-cases-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 1.5rem; margin-bottom: 6rem; }
.use-case-card {
    background: var(--bg-card); padding: 2.5rem; border-radius: 24px; border: 1px solid var(--border);
    text-align: center; transition: 0.3s;
}
.use-case-card:hover { transform: translateY(-10px); border-color: var(--primary); }
.use-case-card .icon { font-size: 2.5rem; display: block; margin-bottom: 1rem; }
.use-case-card h4 { margin-bottom: 10px; color: var(--primary); font-weight: 700; }
.use-case-card p { font-size: 0.9rem; color: var(--text-muted); }

/* FAQ */
.pro-article { border-top: 1px solid var(--border); padding-top: 6rem; }
.faq-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(350px, 1fr)); gap: 1.5rem; margin-top: 3rem; }
.faq-item { background: var(--bg-card); padding: 2rem; border-radius: 20px; border: 1px solid var(--border); }
.faq-item h4 { color: var(--primary); margin-bottom: 12px; }

.main-footer { text-align: center; margin-top: 6rem; opacity: 0.5; font-size: 0.85rem; padding-bottom: 4rem; }

@media (max-width: 600px) {
    .main-header h1 { font-size: 2.8rem; }
    .download-group, .faq-grid { grid-template-columns: 1fr; }
    .generator-card { padding: 2rem; }
}