/* Color Tokens & Typography Variables - Bright / Optimistic Theme */
:root {
    --bg-color: #ffffff;
    --bg-surface: #f8fafc; 
    --text-primary: #0f172a;
    --text-secondary: #475569;
    
    --accent-primary: #10b981; 
    --accent-secondary: #f59e0b; 
    --accent-warm: #ec4899; 
    
    --focus-color: #0ea5e9;
    
    --font-primary: 'Helvetica Neue', Arial, sans-serif;
    --font-heading: 'Georgia', serif;

    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: var(--font-primary);
    color: var(--text-primary);
    background-color: var(--bg-color);
    line-height: 1.7;
    overflow-x: hidden;
}

/* Accessibility */
.skip-link {
    position: absolute; top: -50px; left: 0;
    background: var(--accent-primary); color: #fff;
    padding: 10px; z-index: 100; transition: top 0.3s;
}
.skip-link:focus { top: 0; }
*:focus { outline: 2px solid var(--focus-color); outline-offset: 4px; }

/* Layout */
.container { width: 90%; max-width: 1100px; margin: 0 auto; }
.text-center { text-align: center; }

/* Header */
.site-header {
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid #e2e8f0;
    padding: 1.2rem 0;
    position: sticky; top: 0; z-index: 50;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}
.header-inner { display: flex; flex-wrap: wrap; justify-content: space-between; align-items: center; }
.logo a {
    font-family: var(--font-primary); font-size: 1.5rem; font-weight: 800;
    color: var(--text-primary); text-decoration: none; letter-spacing: 0.5px;
}
.logo .dot { color: var(--accent-primary); }

/* Navigation Animations (Hover underline effect) */
.nav-list { display: flex; list-style: none; gap: 2.5rem; }
.nav-list a {
    position: relative;
    display: inline-block;
    text-decoration: none; 
    color: var(--text-secondary);
    font-size: 0.95rem; 
    font-weight: 600; 
    transition: var(--transition);
}
.nav-list a::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: -4px;
    left: 50%;
    background-color: var(--accent-primary);
    transition: all 0.3s ease-in-out;
    transform: translateX(-50%);
}
.nav-list a:hover::after, .nav-list a[aria-current="page"]::after {
    width: 100%;
}
.nav-list a:hover {
    color: var(--accent-primary);
    transform: translateY(-1px);
}

/* Hero Section with Background Photo */
.hero {
    position: relative;
    padding: 10rem 0;
    text-align: center;
    /* Custom classroom background image */
    background: url('bg.jpg') center/cover no-repeat;
}

/* White overlay to keep the image bright but text readable */
.hero::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(255, 255, 255, 0.85); /* 85% opacity white overlay so it faintly shows */
    z-index: 0;
}

.hero-content { position: relative; z-index: 1; }

.badge {
    display: inline-block; padding: 0.4rem 1.2rem; margin-bottom: 1.5rem;
    background: #fffbeb; color: var(--accent-primary);
    border: 1px solid #bae6fd; border-radius: 50px;
    font-size: 0.85rem; font-weight: 700; letter-spacing: 1px; text-transform: uppercase;
    box-shadow: 0 4px 6px rgba(14, 165, 233, 0.1);
}
.hero h1 {
    font-family: var(--font-heading); font-size: 4rem; line-height: 1.2;
    margin-bottom: 1.5rem; color: #0f172a;
    text-shadow: 0 2px 4px rgba(255,255,255,0.5);
}
.hero .highlight {
    background: linear-gradient(120deg, var(--accent-primary), var(--accent-secondary));
    -webkit-background-clip: text; -webkit-text-fill-color: transparent;
}
.hero p {
    font-size: 1.25rem; color: var(--text-secondary); max-width: 700px;
    margin: 0 auto 3rem;
    font-weight: 500;
}

/* Animated Button with Scale and Shine Sweep */
.btn {
    display: inline-block; padding: 0.8rem 2.8rem; text-decoration: none;
    border-radius: 8px; font-weight: bold; 
    transition: var(--transition);
}
.btn-primary {
    position: relative;
    overflow: hidden;
    background-color: var(--accent-primary); color: #fff;
    box-shadow: 0 4px 14px rgba(14, 165, 233, 0.25);
    z-index: 1; /* Required for the shine effect */
}

.btn-primary::after {
    content: '';
    position: absolute;
    top: 0; left: -100%; width: 50%; height: 100%;
    background: linear-gradient(to right, rgba(255,255,255,0) 0%, rgba(255,255,255,0.3) 50%, rgba(255,255,255,0) 100%);
    transform: skewX(-25deg);
    transition: all 0.6s ease;
    z-index: -1;
}

.btn-primary:hover { 
    background-color: #0284c7; 
    transform: scale(1.05) translateY(-3px); 
    box-shadow: 0 10px 25px rgba(14, 165, 233, 0.4); 
}
.btn-primary:hover::after {
    left: 150%;
}


/* Sections with Soft Colors */
#vision {
    background: linear-gradient(135deg, #fffbeb 0%, #ffffff 100%); /* Απαλό φωτεινό γαλάζιο */
}
.section { padding: 6rem 0; }
.split-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 4rem; align-items: center; }
.section-title { font-family: var(--font-heading); font-size: 2.5rem; margin-bottom: 1.5rem; color: #0f172a; }
.section-subtitle { color: var(--text-secondary); margin-bottom: 3rem; font-size: 1.1rem; }

/* Bright Abstract Shape */
.bright-shape {
    width: 100%; aspect-ratio: 1;
    background: linear-gradient(45deg, #fffbeb, #f8fafc);
    border: 1px solid #e2e8f0; border-radius: 30px;
    position: relative; overflow: hidden;
    box-shadow: inset 0 0 20px rgba(14, 165, 233, 0.05);
}
.bright-shape::after {
    content: ''; position: absolute; top: -50%; left: -50%; width: 200%; height: 200%;
    background: conic-gradient(from 0deg, transparent, rgba(16, 185, 129, 0.1), transparent);
    animation: rotate 20s linear infinite;
}
@keyframes rotate { 100% { transform: rotate(360deg); } }

/* Cards (Light UI) with Soft Color */
.light-grey-section { 
    background: linear-gradient(135deg, #ffffff 0%, #f0fdf4 100%); /* Απαλό πράσινο της ελπίδας */
    border-top: 1px solid #f1f5f9;
}
.card-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 2.5rem; }
.card {
    background: #ffffff;
    border: 1px solid #f1f5f9;
    padding: 2.5rem; border-radius: 16px;
    transition: var(--transition);
    position: relative; overflow: hidden;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -1px rgba(0, 0, 0, 0.03);
}
.card::before {
    content: ''; position: absolute; top: 0; left: 0; width: 100%; height: 4px;
    background: linear-gradient(90deg, var(--accent-primary), var(--accent-secondary));
    opacity: 0; transition: var(--transition);
}
.card:hover, .card:focus-within {
    transform: translateY(-5px);
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
}
.card:hover::before { opacity: 1; }
.card h3 { color: var(--text-primary); margin-bottom: 1rem; font-size: 1.4rem; font-family: var(--font-heading); }
.card p { color: var(--text-secondary); margin-bottom: 1.5rem; font-size: 1rem; }
.card .date { 
    font-size: 0.85rem; color: var(--accent-primary); font-weight: bold;
    display: block; margin-bottom: 0.8rem; letter-spacing: 0.5px; 
}
.loading-text { color: var(--text-secondary); font-style: italic; }

/* === BLOG / ARTICLE STYLES === */
.article-section {
    padding: 6rem 0 4rem;
    max-width: 800px;
    margin: 0 auto;
}
.article-section .date {
    display: block;
    color: var(--accent-primary);
    font-weight: bold;
    margin-bottom: 1rem;
}
.article-title {
    font-family: var(--font-heading);
    font-size: 3rem;
    color: var(--text-primary);
    margin-bottom: 2rem;
    line-height: 1.2;
}
.article-body {
    font-size: 1.15rem;
    color: var(--text-secondary);
    line-height: 1.8;
}
.article-body p {
    margin-bottom: 1.5rem;
}
.read-more {
    display: inline-block;
    margin-top: 1rem;
    color: var(--accent-primary);
    font-weight: 700;
    text-decoration: none;
    transition: var(--transition);
}
.read-more:hover {
    color: var(--accent-warm);
    transform: translateX(4px);
}

/* Footer */
.site-footer {
    background: #0f172a; 
    color: #cbd5e1;
    padding: 3rem 0;
    font-size: 0.95rem;
}
.footer-inner { display: flex; justify-content: space-between; flex-wrap: wrap; align-items: center;}
.footer-links { list-style: none; display: flex; gap: 1.5rem; }
.footer-links a { color: #cbd5e1; text-decoration: none; transition: color 0.2s;}
.footer-links a:hover { color: #fff; }

/* === TEACHERS, SCHEDULE & CONTACT === */
.teachers-grid {
    display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 2rem; margin-top: 2rem;
}
.teacher-card {
    background: #fff; border-left: 4px solid var(--accent-secondary);
    padding: 1.5rem; border-radius: 8px; box-shadow: 0 4px 6px rgba(0,0,0,0.02);
    transition: transform 0.2s;
}
.teacher-card:hover { transform: translateY(-3px); }
.teacher-card h3 { color: var(--text-primary); margin-bottom: 0.5rem; font-size: 1.2rem; }
.teacher-card .specialty { color: var(--accent-primary); font-weight: 600; font-size: 0.95rem; }

.table-responsive { overflow-x: auto; margin-top: 2rem; box-shadow: 0 4px 15px rgba(0,0,0,0.03); border-radius: 12px; }
.schedule-table { width: 100%; border-collapse: collapse; background: #fff; text-align: left; }
.schedule-table th, .schedule-table td { padding: 1.2rem; border-bottom: 1px solid #e2e8f0; }
.schedule-table th { background: #fffbeb; color: var(--text-primary); font-family: var(--font-heading); font-size: 1.1rem; }
.schedule-table tr:hover { background: #f8fafc; }

.contact-list { list-style: none; margin-top: 2rem; }
.contact-list li { margin-bottom: 1.2rem; font-size: 1.1rem; color: var(--text-secondary); }
.contact-list a { color: var(--accent-primary); text-decoration: none; font-weight:bold; }
.contact-list a:hover { text-decoration:underline; }

.contact-box {
    background: #fff; padding: 3rem; border-radius: 16px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.06); text-align: center;
}
.contact-box h3 { font-family: var(--font-heading); font-size: 1.8rem; margin-bottom: 1rem; color: var(--text-primary); }

/* Mobile */
@media (max-width: 768px) {
    .site-header { padding: 0.8rem 0; }
    .split-grid { grid-template-columns: 1fr; }
    .hero { padding: 6rem 0; }
    .hero h1 { font-size: 2.8rem; }
    .header-inner { flex-direction: column; gap: 1rem; }
    .nav-list { flex-direction: row; flex-wrap: wrap; justify-content: center; gap: 0.8rem; margin-top: 0.5rem; }
    .nav-list a { font-size: 0.95rem; }
    .footer-inner { flex-direction: column; text-align: center; gap: 1.5rem; }
    .footer-links { justify-content: center; }
    .article-title { font-size: 2.2rem; }
}