/* Core Styling & Design System */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #667eea;
    --secondary-color: #764ba2;
    --accent-color: #f093fb;
    --text-dark: #2d3748;
    --text-light: #718096;
    --bg-light: #f7fafc;
    --white: #ffffff;
    --shadow: 0 10px 25px rgba(0,0,0,0.1);
    --shadow-hover: 0 20px 40px rgba(0,0,0,0.15);
    
    --bg-gradient-start: #f7fafc;
    --bg-gradient-end: #e2e8f0;
    
    --navbar-bg: rgba(255, 255, 255, 0.95);
    --navbar-bg-scroll: rgba(255, 255, 255, 0.98);
    --card-border: #e2e8f0;
}

[data-theme="dark"] {
    --text-dark: #f8fafc;
    --text-light: #94a3b8;
    --bg-light: #0f172a;
    --white: #1e293b;
    --shadow: 0 10px 25px rgba(0,0,0,0.3);
    --shadow-hover: 0 20px 40px rgba(0,0,0,0.5);
    
    --bg-gradient-start: #0f172a;
    --bg-gradient-end: #020617;
    
    --navbar-bg: rgba(15, 23, 42, 0.95);
    --navbar-bg-scroll: rgba(15, 23, 42, 0.98);
    --card-border: #334155;
}

body {
    font-family: 'Inter', sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background: linear-gradient(135deg, var(--bg-gradient-start) 0%, var(--bg-gradient-end) 100%);
    min-height: 100vh;
    transition: background 0.3s ease, color 0.3s ease;
}

/* Modern Navigation */
.navbar {
    background: var(--navbar-bg);
    backdrop-filter: blur(10px);
    padding: 1rem 0;
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 20px rgba(0,0,0,0.1);
    transition: all 0.3s ease;
    border-bottom: 1px solid var(--card-border);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    text-decoration: none;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 1.5rem;
    align-items: center;
}

.nav-link {
    text-decoration: none;
    color: var(--text-dark);
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 25px;
    transition: all 0.3s ease;
}

.nav-link:hover, .nav-link.active {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    transform: translateY(-2px);
}

/* Controls (Theme & Lang) */
.nav-controls {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-left: auto;
    margin-right: 1.5rem;
}

.theme-toggle-btn {
    background: var(--white);
    border: 1px solid var(--card-border);
    width: 40px;
    height: 40px;
    border-radius: 50%;
    color: var(--text-dark);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    transition: all 0.3s ease;
    box-shadow: var(--shadow);
}

.theme-toggle-btn:hover {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border-color: transparent;
    transform: rotate(15deg) scale(1.05);
}

.lang-switcher {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    border: 1px solid var(--card-border);
    padding: 0.2rem 0.6rem;
    border-radius: 20px;
    background: var(--white);
    box-shadow: var(--shadow);
    height: 40px;
}

.lang-btn {
    text-decoration: none;
    color: var(--text-light);
    font-weight: 600;
    font-size: 0.85rem;
    padding: 0.2rem 0.5rem;
    border-radius: 12px;
    transition: all 0.3s ease;
}

.lang-btn.active {
    color: white !important;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
}

.lang-btn:hover:not(.active) {
    color: var(--primary-color);
}

.lang-divider {
    color: var(--text-light);
    font-size: 0.8rem;
    opacity: 0.5;
}

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

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    width: 100%;
}

/* Animations */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 0.8s ease forwards;
}

@keyframes fadeInUp {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.delay-1 { animation-delay: 0.2s; }
.delay-2 { animation-delay: 0.4s; }
.delay-3 { animation-delay: 0.6s; }
.delay-4 { animation-delay: 0.8s; }

/* Responsive adjustments for Navigation */
@media (max-width: 968px) {
    .nav-container {
        padding: 0 1rem;
    }
}

@media (max-width: 768px) {
    .mobile-toggle {
        display: block;
    }

    .nav-menu {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background: var(--white);
        flex-direction: column;
        padding: 1.5rem 2rem;
        box-shadow: var(--shadow);
        gap: 1rem;
        align-items: stretch;
        border-top: 1px solid var(--card-border);
    }

    .nav-menu.active {
        display: flex;
    }

    .nav-link {
        text-align: center;
    }

    .nav-controls {
        margin-left: auto;
        margin-right: 1rem;
    }
}