/* 
============ HF ELEKTRİK - PREMIUM STYLES ============
*/

:root {
    --primary: #fbbf24;       /* Gold/Yellow */
    --primary-dark: #d97706;  /* Deep Gold */
    --secondary: #3b82f6;     /* Bright Blue from Logo */
    --bg-main: #020617;       /* Very Dark Blue/Black */
    --bg-card: #0f172a;       /* Dark Blue for Cards */
    --bg-card-hover: #1e293b; 
    --text-main: #f8fafc;     /* White/Off-white */
    --text-muted: #94a3b8;    /* Soft Gray */
    --border: #334155;
    
    --whatsapp: #25d366;
    --whatsapp-dark: #128c7e;

    --font: 'Outfit', sans-serif;
    
    --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font);
    background-color: var(--bg-main);
    color: var(--text-main);
    line-height: 1.6;
    overflow-x: hidden;
}

ul { list-style: none; }
a { text-decoration: none; color: inherit; }
img { max-width: 100%; height: auto; display: block; }

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Typography */
h1, h2, h3, h4, h5 { font-weight: 700; line-height: 1.2; }
.section-subtitle {
    color: var(--primary);
    text-transform: uppercase;
    letter-spacing: 2px;
    font-weight: 600;
    font-size: 0.9rem;
    margin-bottom: 10px;
    display: inline-block;
}
.section-title {
    font-size: 2.5rem;
    margin-bottom: 20px;
}
.text-center { text-align: center; }

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 24px;
    border-radius: 50px;
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: var(--transition);
    border: none;
    outline: none;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: #000;
    box-shadow: 0 4px 15px rgba(251, 191, 36, 0.3);
}
.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(251, 191, 36, 0.5);
}

.btn-whatsapp-lg {
    background: var(--whatsapp);
    color: #fff;
    font-size: 1.1rem;
    padding: 15px 30px;
    box-shadow: 0 4px 15px rgba(37, 211, 102, 0.3);
}
.btn-whatsapp-lg:hover {
    background: var(--whatsapp-dark);
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(37, 211, 102, 0.5);
}

.btn-outline {
    background: transparent;
    color: var(--text-main);
    border: 2px solid var(--border);
    padding: 13px 30px;
}
.btn-outline:hover {
    border-color: var(--primary);
    color: var(--primary);
}

.btn-campaign {
    background: #fff;
    color: #000;
}
.btn-campaign:hover {
    background: var(--primary);
}

/* Header */
.header {
    background: rgba(2, 6, 23, 0.85); /* Glassmorphism */
    backdrop-filter: blur(10px);
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    border-bottom: 1px solid rgba(255,255,255,0.05);
    transition: var(--transition);
    padding: 15px 0;
}
.header.scrolled { padding: 10px 0; background: rgba(2, 6, 23, 0.95); }

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

/* --- Premium Shield Logo --- */
.logo-badge {
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo-shield {
    width: 48px;
    height: 52px;
    background: linear-gradient(135deg, var(--secondary), #1e3a8a);
    clip-path: polygon(50% 0%, 100% 15%, 100% 70%, 50% 100%, 0% 70%, 0% 15%);
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    box-shadow: 0 4px 15px rgba(59, 130, 246, 0.4);
}

.logo-initials {
    font-size: 1.2rem;
    font-weight: 800;
    color: #fff;
    letter-spacing: 1px;
    text-shadow: 0 2px 4px rgba(0,0,0,0.3);
}

.logo-text {
    display: flex;
    flex-direction: column;
}

.logo-name {
    font-size: 1.3rem;
    font-weight: 800;
    color: var(--primary);
    letter-spacing: 2px;
    line-height: 1.1;
}

.logo-slogan {
    font-size: 0.65rem;
    color: var(--text-muted);
    font-weight: 400;
    letter-spacing: 1px;
    font-style: italic;
}

.nav-links {
    display: flex;
    gap: 30px;
}

.nav-links a {
    font-weight: 500;
    position: relative;
    padding-bottom: 5px;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary);
    transition: var(--transition);
}
.nav-links a:hover::after { width: 100%; }
.nav-links a:hover { color: var(--primary); }

.header-actions {
    display: flex;
    align-items: center;
    gap: 15px;
}

.menu-toggle {
    display: none;
    background: none;
    border: none;
    color: var(--text-main);
    font-size: 1.5rem;
    cursor: pointer;
}

/* Hero Section */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    background: #020617 url('assets/hero.jpeg') center/cover no-repeat;
    padding-top: 80px; /* Offset for header */
}

.hero-overlay {
    position: absolute;
    top: 0; left: 0; width: 100%; height: 100%;
    background: linear-gradient(to right, #020617 30%, rgba(2, 6, 23, 0.6) 100%);
    z-index: 1;
}

.hero-content {
    position: relative;
    z-index: 2;
    max-width: 800px;
}

.badge {
    display: inline-block;
    background: rgba(251, 191, 36, 0.1);
    color: var(--primary);
    border: 1px solid var(--primary);
    padding: 6px 16px;
    border-radius: 30px;
    font-weight: 600;
    font-size: 0.85rem;
    margin-bottom: 25px;
}

.hero-title {
    font-size: 4.5rem;
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: 25px;
}

.hero-title .highlight {
    color: var(--primary);
    text-shadow: 0 0 20px rgba(251, 191, 36, 0.3);
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-muted);
    margin-bottom: 40px;
    max-width: 600px;
}

.hero-buttons {
    display: flex;
    gap: 20px;
    margin-bottom: 50px;
}

.hero-features {
    display: flex;
    gap: 30px;
    flex-wrap: wrap;
}

.feature-item {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 500;
    color: var(--text-main);
    background: rgba(255, 255, 255, 0.05);
    padding: 10px 20px;
    border-radius: 8px;
    border: 1px solid rgba(255, 255, 255, 0.1);
}
.feature-item i { color: var(--primary); }

/* Campaign Banner */
.campaign-banner {
    background: linear-gradient(135deg, var(--secondary), #1e3a8a);
    padding: 30px 0;
    position: relative;
    overflow: hidden;
}

.campaign-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 30px;
    position: relative;
    z-index: 2;
}

.campaign-icon {
    font-size: 3rem;
    color: var(--primary);
}

.campaign-text h3 {
    font-size: 1.8rem;
    margin-bottom: 5px;
}

.campaign-text strong {
    color: var(--primary);
}

/* About Section */
.about {
    padding: 100px 0;
}

.about-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.about-image {
    position: relative;
}

.rounded-shadow {
    border-radius: 20px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.5);
    border: 1px solid var(--border);
}

.experience-badge {
    position: absolute;
    bottom: -30px;
    right: -30px;
    background: var(--primary);
    color: #000;
    width: 150px;
    height: 150px;
    border-radius: 50%;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    border: 10px solid var(--bg-main);
    box-shadow: 0 10px 20px rgba(0,0,0,0.3);
}

.experience-badge .number {
    font-size: 2.5rem;
    font-weight: 800;
    line-height: 1;
}

.experience-badge .text {
    font-size: 0.9rem;
    font-weight: 600;
}

.lead-text {
    font-size: 1.25rem;
    color: var(--text-main);
    margin-bottom: 20px;
    font-weight: 500;
}

.about-text p {
    color: var(--text-muted);
    margin-bottom: 30px;
}

.about-list {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
    margin-bottom: 40px;
}

.about-list li {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 500;
}

.about-list li i { color: var(--primary); }

.about-auth {
    display: flex;
    gap: 20px;
    border-top: 1px solid var(--border);
    padding-top: 30px;
}

.auth-box {
    display: flex;
    align-items: center;
    gap: 15px;
    background: var(--bg-card);
    padding: 15px 25px;
    border-radius: 12px;
    border: 1px solid var(--border);
    transition: var(--transition);
}
.auth-box i { font-size: 1.5rem; color: var(--primary); }
.auth-box span { font-weight: 600; font-size: 1.1rem; }

.auth-box-wa {
    cursor: pointer;
    text-decoration: none;
    color: var(--text-main);
}
.auth-box-wa:hover {
    transform: translateY(-5px);
    border-color: var(--whatsapp);
    box-shadow: 0 10px 20px rgba(37, 211, 102, 0.2);
}
.auth-box-wa:hover i {
    color: var(--whatsapp);
}

/* Services Section */
.services {
    padding: 100px 0;
    background: #060b19;
}

.section-desc {
    color: var(--text-muted);
    max-width: 600px;
    margin: 0 auto 50px;
}

.services-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.service-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 40px 30px;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.service-card::before {
    content: '';
    position: absolute;
    top: 0; left: 0; width: 100%; height: 4px;
    background: linear-gradient(90deg, var(--primary), transparent);
    transform: scaleX(0);
    transform-origin: left;
    transition: var(--transition);
}

.service-card:hover {
    transform: translateY(-10px);
    background: var(--bg-card-hover);
    box-shadow: 0 20px 40px rgba(0,0,0,0.4);
}

.service-card:hover::before { transform: scaleX(1); }

.service-icon {
    font-size: 3rem;
    color: var(--primary);
    margin-bottom: 25px;
}

.service-card h3 {
    font-size: 1.4rem;
    margin-bottom: 15px;
}

.service-card p {
    color: var(--text-muted);
}

/* Pricing Info Section */
.pricing-info {
    padding: 100px 0;
    text-align: center;
    background: #020617 url('assets/pricing.jpeg') center/cover fixed;
    position: relative;
}

.pricing-overlay {
    position: absolute;
    top: 0; left: 0; width: 100%; height: 100%;
    background: rgba(2, 6, 23, 0.85);
}

.pricing-container {
    position: relative;
    z-index: 2;
    max-width: 800px;
}

.pricing-desc {
    font-size: 1.2rem;
    color: #e2e8f0;
    margin-bottom: 40px;
}

/* Instagram Showcase Section */
.instagram-section {
    padding: 100px 0;
}

.instagram-card {
    max-width: 550px;
    margin: 0 auto;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 20px;
    padding: 40px;
    text-align: center;
    position: relative;
    overflow: hidden;
    transition: var(--transition);
}

.instagram-card::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 4px;
    background: linear-gradient(90deg, #f09433, #e6683c, #dc2743, #cc2366, #bc1888);
}

.instagram-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 40px rgba(0,0,0,0.3);
}

.insta-header {
    display: flex;
    align-items: center;
    gap: 20px;
    margin-bottom: 25px;
}

.insta-avatar {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    background: linear-gradient(45deg, #f09433, #e6683c, #dc2743, #cc2366, #bc1888);
    padding: 3px;
    flex-shrink: 0;
}

.insta-avatar-inner {
    width: 100%;
    height: 100%;
    background: var(--bg-card);
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
}

.insta-avatar-inner i {
    font-size: 2rem;
    color: var(--primary);
}

.insta-info {
    text-align: left;
}

.insta-username {
    font-size: 1.3rem;
    font-weight: 700;
    margin-bottom: 4px;
}

.insta-bio {
    color: var(--text-muted);
    font-size: 0.95rem;
}

.insta-stats {
    display: flex;
    justify-content: center;
    gap: 40px;
    padding: 20px 0;
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
    margin-bottom: 20px;
}

.insta-stat {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 5px;
}

.insta-stat i {
    font-size: 1.5rem;
    color: var(--primary);
}

.insta-stat span {
    font-size: 0.85rem;
    color: var(--text-muted);
    font-weight: 500;
}

.insta-desc {
    color: var(--text-muted);
    line-height: 1.8;
    margin-bottom: 25px;
    font-size: 0.95rem;
    text-align: left;
}

.btn-instagram {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 14px 30px;
    border-radius: 10px;
    font-weight: 700;
    font-size: 1rem;
    color: #fff;
    background: linear-gradient(45deg, #f09433, #e6683c, #dc2743, #cc2366, #bc1888);
    background-size: 200% 200%;
    animation: instaGradient 3s ease infinite;
    transition: var(--transition);
    text-decoration: none;
}

.btn-instagram:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(220, 39, 67, 0.4);
}

@keyframes instaGradient {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

/* FAQ Section */
.faq {
    padding: 100px 0;
    background: #060b19;
}

.faq-container { max-width: 800px; margin: 0 auto; }

.accordion {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.accordion-item {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 10px;
    overflow: hidden;
}

.accordion-header {
    width: 100%;
    text-align: left;
    padding: 20px 25px;
    background: none;
    border: none;
    color: var(--text-main);
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: var(--transition);
}

.accordion-header:hover { background: rgba(255,255,255,0.02); color: var(--primary); }

.accordion-header i { transition: var(--transition); }

.accordion-item.active .accordion-header { color: var(--primary); border-bottom: 1px solid var(--border); }
.accordion-item.active .accordion-header i { transform: rotate(180deg); }

.accordion-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease-out;
    background: rgba(0,0,0,0.2);
}

.accordion-content p {
    padding: 20px 25px;
    color: var(--text-muted);
}

/* Footer */
.footer {
    background: #020617;
    border-top: 1px solid var(--border);
    padding-top: 80px;
}

.footer-top {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 50px;
    margin-bottom: 50px;
}

.footer-logo { max-width: 200px; margin-bottom: 20px; }
.brand-col p { color: var(--text-muted); margin-bottom: 25px; }

.social-links { display: flex; gap: 15px; }
.social-links a {
    display: inline-flex;
    justify-content: center;
    align-items: center;
    width: 40px; height: 40px;
    background: rgba(255,255,255,0.05);
    border-radius: 50%;
    border: 1px solid var(--border);
    transition: var(--transition);
}
.social-links a:hover {
    background: var(--primary);
    color: #000;
    border-color: var(--primary);
}

.footer-col h3 {
    font-size: 1.3rem;
    margin-bottom: 25px;
    position: relative;
    padding-bottom: 10px;
}
.footer-col h3::after {
    content: '';
    position: absolute;
    bottom: 0; left: 0;
    width: 40px; height: 2px;
    background: var(--primary);
}

.links-col ul { display: flex; flex-direction: column; gap: 12px; }
.links-col a { color: var(--text-muted); transition: var(--transition); }
.links-col a:hover { color: var(--primary); padding-left: 5px; }

.contact-list { display: flex; flex-direction: column; gap: 20px; }
.contact-list li {
    display: flex;
    gap: 15px;
    color: var(--text-muted);
}
.contact-list i { color: var(--primary); font-size: 1.2rem; margin-top: 3px; }
.contact-list .phones { display: flex; flex-direction: column; gap: 5px; }
.contact-list a { color: var(--text-muted); }
.contact-list a:hover { color: var(--primary); }

.footer-bottom {
    background: #000;
    padding: 20px 0;
    text-align: center;
    color: #475569;
    font-size: 0.9rem;
}

/* Floating WhatsApp Button */
.floating-whatsapp {
    position: fixed;
    bottom: 30px;
    right: 30px;
    background: var(--whatsapp);
    color: white;
    width: 65px;
    height: 65px;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 2rem;
    box-shadow: 0 4px 20px rgba(37, 211, 102, 0.4);
    z-index: 100;
    transition: var(--transition);
    text-decoration: none;
    animation: pulse 2s infinite;
}

.floating-whatsapp:hover {
    transform: scale(1.1);
    background: var(--whatsapp-dark);
}

/* Tooltip on Hover */
.tooltip-text {
    position: absolute;
    right: 80px;
    top: 50%;
    transform: translateY(-50%);
    background: #fff;
    color: #000;
    padding: 8px 15px;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 600;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
    white-space: nowrap;
    box-shadow: 0 4px 10px rgba(0,0,0,0.2);
}

.floating-whatsapp:hover .tooltip-text {
    opacity: 1;
    visibility: visible;
}

@keyframes pulse {
    0% { box-shadow: 0 0 0 0 rgba(37, 211, 102, 0.7); }
    70% { box-shadow: 0 0 0 15px rgba(37, 211, 102, 0); }
    100% { box-shadow: 0 0 0 0 rgba(37, 211, 102, 0); }
}

/* ---------- RESPONSIVE DESIGN ---------- */
@media (max-width: 992px) {
    .hero-title { font-size: 3.5rem; }
    .services-grid { grid-template-columns: repeat(2, 1fr); }
    .footer-top { grid-template-columns: 1fr 1fr; }
    .brand-col { grid-column: 1 / -1; }
}

@media (max-width: 768px) {
    .menu-toggle { display: block; }
    
    .navbar {
        position: fixed;
        top: 0; left: -100%; width: 280px; height: 100vh;
        background: var(--bg-card);
        border-right: 1px solid var(--border);
        transition: var(--transition);
        display: flex;
        align-items: center;
        justify-content: center;
    }
    .navbar.active { left: 0; box-shadow: 10px 0 30px rgba(0,0,0,0.5); }
    
    .nav-links {
        flex-direction: column;
        gap: 30px;
        text-align: center;
        font-size: 1.2rem;
    }
    
    .btn-call { display: none; } /* Hide in header on mobile to save space */
    
    .hero-title { font-size: 2.5rem; }
    .hero-buttons { flex-direction: column; }
    
    .campaign-container { flex-direction: column; text-align: center; }
    
    .about-container { grid-template-columns: 1fr; }
    
    .experience-badge { bottom: 20px; right: 20px; width: 120px; height: 120px; }
    .experience-badge .number { font-size: 2rem; }
    
    .services-grid { grid-template-columns: 1fr; }
    .footer-top { grid-template-columns: 1fr; }
    
    /* Contact Modal Mobile Adjustments */
    .contact-modal-content {
        padding: 30px 20px;
        width: 95%;
    }
    
    .modal-icon {
        font-size: 2.5rem;
        margin-bottom: 15px;
    }
    
    #modalTitle {
        font-size: 1.25rem;
    }
    
    .btn-modal-primary {
        padding: 12px 20px;
        flex-direction: column;
        gap: 5px;
    }
    
    .ust-name {
        font-size: 1rem;
    }
    
    .ust-phone {
        font-size: 0.95rem;
    }
}

/* ---------- CONTACT MODAL ---------- */
.contact-modal {
    position: fixed;
    top: 0; left: 0; width: 100%; height: 100%;
    background: rgba(2, 6, 23, 0.9);
    z-index: 9999;
    display: flex;
    justify-content: center;
    align-items: center;
    opacity: 0;
    visibility: hidden;
    backdrop-filter: blur(5px);
    transition: var(--transition);
}

.contact-modal.active {
    opacity: 1;
    visibility: visible;
}

.contact-modal-content {
    background: var(--bg-card);
    width: 90%;
    max-width: 450px;
    padding: 40px;
    border-radius: 20px;
    border: 1px solid var(--border);
    position: relative;
    text-align: center;
    transform: translateY(30px) scale(0.95);
    transition: all 0.4s cubic-bezier(0.25, 0.8, 0.25, 1);
    box-shadow: 0 25px 50px rgba(0,0,0,0.5);
}

.contact-modal.active .contact-modal-content {
    transform: translateY(0) scale(1);
}

.close-modal {
    position: absolute;
    top: 15px;
    right: 20px;
    background: transparent;
    border: none;
    color: var(--text-muted);
    font-size: 2rem;
    cursor: pointer;
    line-height: 1;
    transition: var(--transition);
}

.close-modal:hover {
    color: var(--primary);
    transform: rotate(90deg);
}

.modal-icon {
    font-size: 3.5rem;
    color: var(--primary);
    margin-bottom: 20px;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

#modalTitle {
    font-size: 1.5rem;
    margin-bottom: 10px;
}

.contact-modal-content p {
    color: var(--text-muted);
    font-size: 0.95rem;
    margin-bottom: 30px;
}

.modal-buttons {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.btn-modal-primary {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 25px;
    background: rgba(255,255,255,0.03);
    border: 1px solid var(--border);
    border-radius: 12px;
    text-decoration: none;
    transition: var(--transition);
}

.btn-modal-primary:hover {
    background: linear-gradient(135deg, rgba(251, 191, 36, 0.1), transparent);
    border-color: var(--primary);
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(0,0,0,0.2);
}

.ust-name {
    font-weight: 700;
    font-size: 1.1rem;
    color: var(--text-main);
}

.ust-phone {
    font-weight: 600;
    color: var(--primary);
}

/* ---------- ANIMATIONS & MICRO-INTERACTIONS ---------- */
.reveal {
    opacity: 0;
    transform: translateY(40px);
    transition: all 0.8s cubic-bezier(0.25, 0.8, 0.25, 1);
}

.reveal.active {
    opacity: 1;
    transform: translateY(0);
}

.delay-1 { transition-delay: 0.1s; }
.delay-2 { transition-delay: 0.2s; }
.delay-3 { transition-delay: 0.3s; }
.delay-4 { transition-delay: 0.4s; }

/* Enhanced hover states everywhere */
.nav-links a::after {
    height: 3px;
    border-radius: 3px;
}

.btn {
    position: relative;
    overflow: hidden;
    z-index: 1;
}

.btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 300px;
    height: 300px;
    background: rgba(255,255,255,0.1);
    border-radius: 50%;
    transform: translate(-50%, -50%) scale(0);
    transition: transform 0.5s ease;
    z-index: -1;
}

.btn:hover::before {
    transform: translate(-50%, -50%) scale(1);
}