:root {
    --primary: #3b82f6;
    --dark: #0f0f0f;
    --darker: #121212;
    --text: #e5e7eb;
    --text-muted: #9ca3af;
    --card-bg: rgba(255, 255, 255, 0.03);
    --border: rgba(255, 255, 255, 0.1);
    --font-heading: 'Montserrat', sans-serif;
    --font-body: 'Inter', sans-serif;
}

/* Base Reset */
* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body { 
    background-color: var(--dark); 
    color: var(--text); 
    font-family: var(--font-body); 
    line-height: 1.6; 
    overflow-x: hidden; 
}
a { text-decoration: none; color: inherit; transition: 0.3s; }
img { max-width: 100%; height: auto; display: block; }
ul { list-style: none; }

/* Utilities */
.container { width: 100%; max-width: 1200px; margin: 0 auto; padding: 0 1.5rem; }
.section { padding: 3rem 0; }
.text-center { text-align: center; }
.bg-darker { background-color: var(--darker); }
.text-red { color: #ef4444; }
.text-green { color: #22c55e; }
.text-blue { color: var(--primary); }
.text-muted { color: var(--text-muted); }
.text-glow { text-shadow: 0 0 20px rgba(59, 130, 246, 0.5); }
.underline-red { border-bottom: 2px solid #ef4444; color: white; }
.underline-green { text-decoration: underline; text-decoration-color: #22c55e; text-underline-offset: 4px; }
.underline-blue { text-decoration: underline; text-decoration-color: var(--primary); text-underline-offset: 4px; }
.underline-orange { text-decoration: underline; text-decoration-color: #f97316; text-underline-offset: 4px; }
.small-caps { text-transform: uppercase; letter-spacing: 2px; font-size: 0.8rem; margin-bottom: 1.5rem; }
.text-small { font-size: 0.8rem; color: var(--text-muted); margin-top: 0.5rem; }

/* Typography */
h1, h2, h3, h4 { font-family: var(--font-heading); font-weight: 700; color: white; margin-bottom: 1rem; }
h1 { font-size: 2.2rem; line-height: 1.2; font-weight: 900; } /* Μέγεθος για κινητά */
h1 span { color: var(--primary); }
h2 { font-size: 1.8rem; }
p.subtitle { color: var(--text-muted); margin-bottom: 2rem; }
p.lead { font-size: 1.1rem; color: var(--text); margin-bottom: 1.5rem; }

/* Navbar */
.navbar { position: absolute; top: 0; left: 0; width: 100%; z-index: 50; padding: 1rem 0; }
.nav-container { display: flex; justify-content: space-between; align-items: center; }
.logo { font-family: var(--font-heading); font-weight: 900; font-size: 1.25rem; color: white; }
.logo span { color: var(--primary); }
.logo small { display: block; font-size: 0.75rem; font-weight: 300; color: var(--text-muted); margin-top: -5px; }
.social-links { display: flex; gap: 10px; }
.social-links a { font-size: 1.4rem; color: var(--text-muted); margin-left: 0.5rem; }
.social-links a:hover { color: var(--primary); transform: scale(1.1); }

/* Hero */
.hero { 
    position: relative; 
    min-height: 85vh; 
    display: flex; 
    align-items: center; 
    text-align: center; 
    color: white; 
    padding: 6rem 1.5rem 3rem 1.5rem; 
}
.hero-bg { position: absolute; inset: 0; z-index: -1; }
.hero-bg img { width: 100%; height: 100%; object-fit: cover; filter: brightness(0.5); }
.hero-bg .overlay { position: absolute; inset: 0; background: linear-gradient(to bottom, transparent, rgba(15,15,15,0.4), var(--dark)); }
.hero-content { position: relative; z-index: 10; max-width: 800px; margin: 0 auto; }
.btn { display: inline-block; margin-top: 20px; padding: 0.75rem 2rem; border-radius: 50px; font-weight: bold; cursor: pointer; border: none; }
.btn-primary { background: white; color: var(--dark); box-shadow: 0 10px 15px -3px rgba(59,130,246,0.2); }
.btn-primary:hover { background: var(--primary); color: white; }

/* ----------------------------------------------------------- */
/* GRIDS & CARDS (MOBILE FIRST: ΟΛΑ ΣΕ 1 ΣΤΗΛΗ)               */
/* ----------------------------------------------------------- */

.grid-2, 
.grid-3 { 
    display: grid; 
    grid-template-columns: 1fr; /* Μία στήλη για κινητά */
    gap: 2rem; 
    align-items: center; 
    text-align: center;
}

.grid-3-small { 
    display: grid; 
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr)); 
    gap: 1rem; 
}

.grid-4 {
    display: grid; 
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); 
    gap: 1rem; 

}
.contact-card{ text-align: left}


/* Glass Card Style */
.glass-card {
    background: var(--card-bg); 
    border: 1px solid var(--border); 
    backdrop-filter: blur(10px);
    padding: 1.5rem; 
    border-radius: 1rem; 
    text-align: center; 
    transition: 0.3s;
}
.glass-card i { font-size: 2rem; color: var(--text-muted); margin-bottom: 0.5rem; }
.glass-card h4 { font-size: 0.9rem; margin-bottom: 0; }

/* --- SOLUTION GRID (Features) FIXED --- */
.solution-grid {
    display: grid;
    grid-template-columns: 1fr; /* 1 Στήλη στο κινητό */
    border: 1px solid #333;
    border-radius: 1rem;
    overflow: hidden;
}

.solution-grid > div { 
    padding: 2rem; 
    border-bottom: 1px solid #333; /* Γραμμή κάτω στο κινητό */
    border-right: none;
    
    /* Εντολές για απόλυτο κεντράρισμα */
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
}

.solution-grid > div:last-child { border-bottom: none; }
.feature-item i { font-size: 2.5rem; color: var(--text-muted); margin-bottom: 1rem; display: block; }

/* Portfolio */
.portfolio-item { 
    position: relative; 
    border-radius: 1rem; 
    overflow: hidden; 
    display: block; 
    height: 250px; 
    border: 1px solid #333; 
    width: 100%;
}
.portfolio-item img { width: 100%; height: 100%; object-fit: cover; transition: 0.7s; }
.portfolio-overlay {
    position: absolute; inset: 0; background: linear-gradient(to top, black, transparent);
    display: flex; flex-direction: column; justify-content: flex-end; padding: 1.5rem;
    opacity: 0; transition: 0.3s;
}
.portfolio-item { transform: scale(1.1); filter: brightness(1.5); }
.portfolio-item, .portfolio-overlay { opacity: 1.0; transform: translateY(0); }
.portfolio-overlay span { color: var(--primary); font-size: 0.8rem; font-weight: bold; text-transform: uppercase; letter-spacing: 1px; }

/* Contact Form */
.contact-card { 
    background: #1e1e1e; 
    padding: 2rem 1.5rem; 
    border-radius: 1.5rem; 
    border: 1px solid var(--border); 
    box-shadow: 0 25px 50px -12px rgba(0,0,0,0.25); 
    width: 100%; 
    max-width: 500px; /* Όριο για PC */
    margin: 0 auto; 
}
.form-group { margin-bottom: 1.25rem; }
.form-group label { display: block; color: var(--primary); font-size: 0.7rem; font-weight: bold; text-transform: uppercase; margin-bottom: 0.5rem; }
.form-group input { width: 100%; background: transparent; border: none; border-bottom: 1px solid #555; color: white; padding: 0.5rem 0; outline: none; transition: 0.3s; font-size: 0.9rem; }
.form-group input:focus { border-color: var(--primary); }
#submit-btn { width: 100%; padding: 0.8rem; border-radius: 50px; background: var(--primary); color: white; border: none; font-weight: bold; cursor: pointer; transition: 0.3s; box-shadow: 0 4px 10px rgba(59,130,246,0.3); }
#submit-btn:hover { background: #2563eb; }
#form-message { display: none; text-align: center; margin-top: 1rem; font-size: 0.8rem; }

/* Footer */
.copyright { text-align: center; border-top: 1px solid #333; padding-top: 2rem; margin-top: 3rem; font-size: 0.8rem; color: var(--text-muted); }
.copyright a { color: var(--primary); }
.copyright a:hover { color: #ef4444; }

/* ----------------------------------------------------------- */
/* DESKTOP STYLES (Μόνο για μεγάλες οθόνες > 768px)            */
/* ----------------------------------------------------------- */
@media (min-width: 768px) {
    
    .section { padding: 5rem 0; }
    h1 { font-size: 3.5rem; }
    h2 { font-size: 2.5rem; }
    
    /* Μετατροπή σε στήλες */
    .grid-2 { grid-template-columns: 1fr 1fr; gap: 4rem; }
    .grid-3 { grid-template-columns: 1fr 1fr 1fr; gap: 2rem; }
    .contact-card{ text-align: left}
    

    .solution-grid > div:hover { background: rgba(255,255,255,0.05); transition: 0.3s; }
    .glass-card:hover { border-color: var(--primary); transform: translateY(-5px); }

    .grid-4 { 
    display: grid; 
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr)); 
    gap: 1rem; 
}

    /* Solution Grid Desktop Style */
    .solution-grid { grid-template-columns: 1fr 1fr 1fr; border: none; }
    .solution-grid > div { border-bottom: none; border-right: 1px solid #333; }
    .solution-grid > div:last-child { border-right: none; }

    .md-text-left { text-align: left; }
    .portfolio-item { height: 300px; }

    .portfolio-item:hover img { transform: scale(1.1); filter: brightness(0.8); }
    .portfolio-item:hover .portfolio-overlay { opacity: 1; transform: translateY(0); }
    .portfolio-overlay span { color: var(--primary); font-size: 0.8rem; font-weight: bold; text-transform: uppercase; letter-spacing: 1px; }
    .contact-card:hover {border-color: var(--primary); transition: 0.3s }

    .copyright { justify-content: center; text-align: center; align-items:center; }
}

/* Mobile Helper */
@media (max-width: 767px) {
    .reverse-mobile { display: flex; flex-direction: column-reverse; gap: 2rem; }
}