/* 
    TPA9I Education - Modern Design System
    Focus: Blues, Whites, and Dark Mode Support
*/

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=Outfit:wght@400;500;600;700;800&display=swap');

:root {
    /* Color Palette - Light Mode */
    --primary: #2563eb;
    --primary-hover: #1d4ed8;
    --primary-light: #dbeafe;
    --bg: #ffffff;
    --bg-alt: #f8fafc;
    --text: #0f172a;
    --text-muted: #64748b;
    --border: #e2e8f0;
    --card-bg: #ffffff;
    --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --glass-bg: rgba(255, 255, 255, 0.8);
    --glass-border: rgba(255, 255, 255, 0.2);

    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-base: 0.3s ease;
    
    /* Spacing */
    --section-padding: clamp(4rem, 10vw, 8rem);
}

[data-theme="dark"] {
    /* Color Palette - Dark Mode */
    --primary: #3b82f6;
    --primary-hover: #60a5fa;
    --primary-light: #1e3a8a;
    --bg: #0f172a;
    --bg-alt: #1e293b;
    --text: #f1f5f9;
    --text-muted: #94a3b8;
    --border: #334155;
    --card-bg: #1e293b;
    --shadow: 0 10px 15px -3px rgb(0 0 0 / 0.3);
    --glass-bg: rgba(15, 23, 42, 0.8);
    --glass-border: rgba(255, 255, 255, 0.05);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg);
    color: var(--text);
    line-height: 1.6;
    transition: background-color var(--transition-base), color var(--transition-base);
    overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
    font-family: 'Outfit', sans-serif;
    font-weight: 700;
    line-height: 1.2;
}

a {
    text-decoration: none;
    color: inherit;
    transition: var(--transition-fast);
}

ul {
    list-style: none;
}

img {
    max-width: 100%;
    display: block;
}

.container {
    width: min(100% - 2rem, 1200px);
    margin-inline: auto;
}

/* --- Navigation --- */
nav {
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    background-color: var(--glass-bg);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--glass-border);
    transition: all var(--transition-base);
}

.nav-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

.logo {
    font-family: 'Outfit', sans-serif;
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--primary);
    letter-spacing: -0.5px;
    text-decoration: none !important;
}

.nav-links {
    display: flex;
    gap: 2rem;
    align-items: center;
}

.nav-links a:hover {
    color: var(--primary);
}

.hamburger {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--text);
    cursor: pointer;
    z-index: 1100; /* Increased z-index */
    padding: 0.5rem;
}

.btn-theme {
    background: none;
    border: 1px solid var(--border);
    padding: 0.5rem;
    border-radius: 8px;
    cursor: pointer;
    color: var(--text);
    display: flex;
    align-items: center;
    justify-content: center;
}

.btn-theme:hover {
    background-color: var(--bg-alt);
}

.btn-login {
    background-color: var(--primary);
    color: #ffffff !important;
    padding: 0.5rem 1.5rem;
    border-radius: 8px;
    font-weight: 600;
    transition: var(--transition-base);
}

.btn-login:hover {
    background-color: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.2);
}

/* --- Hero Section --- */
.hero {
    padding: calc(var(--section-padding) + 4rem) 0 var(--section-padding);
    background: linear-gradient(135deg, var(--bg) 0%, var(--bg-alt) 100%);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -10%;
    right: -5%;
    width: 40%;
    height: 60%;
    background: radial-gradient(circle, var(--primary-light) 0%, transparent 70%);
    filter: blur(80px);
    opacity: 0.4;
    z-index: 0;
}

.hero-grid {
    display: grid;
    grid-template-columns: 1.2fr 1fr;
    gap: 4rem;
    align-items: center;
    position: relative;
    z-index: 1;
}

.hero-content h1 {
    font-size: clamp(2.5rem, 5vw, 4rem);
    margin-bottom: 1.5rem;
    color: var(--text);
}

.hero-content h1 span {
    color: var(--primary);
}

.hero-content p {
    font-size: 1.125rem;
    color: var(--text-muted);
    margin-bottom: 2.5rem;
    max-width: 540px;
}

.hero-actions {
    display: flex;
    gap: 1rem;
}

.btn {
    padding: 0.875rem 2rem;
    border-radius: 12px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-base);
}

.btn-primary {
    background-color: var(--primary);
    color: #ffffff;
    box-shadow: 0 4px 14px 0 rgba(37, 99, 235, 0.39);
}

.btn-primary:hover {
    background-color: var(--primary-hover);
    transform: translateY(-2px);
}

.btn-outline {
    border: 1px solid var(--border);
    color: var(--text);
}

.btn-outline:hover {
    background-color: var(--bg-alt);
}

.hero-image img {
    border-radius: 24px;
    box-shadow: var(--shadow);
    animation: float 6s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-20px); }
}

/* --- Features & Services --- */
.features {
    padding: var(--section-padding) 0;
    background-color: var(--bg);
}

.section-header {
    text-align: center;
    margin-bottom: 4rem;
}

.section-header h2 {
    font-size: clamp(2rem, 4vw, 3rem);
    margin-bottom: 1rem;
}

.section-header p {
    color: var(--text-muted);
    max-width: 600px;
    margin-inline: auto;
}

/* --- Interactive Viewer --- */
.viewer-container {
    display: flex;
    gap: 2rem;
    min-height: 600px;
    transition: all 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
    flex: 1;
    transition: all 0.5s ease;
}

.viewer-container.active .features-grid {
    grid-template-columns: 1fr;
    max-width: 320px;
    height: 600px;
    overflow-y: auto;
    padding-right: 1rem;
}

/* Scrollbar for LHS grid */
.viewer-container.active .features-grid::-webkit-scrollbar {
    width: 4px;
}
.viewer-container.active .features-grid::-webkit-scrollbar-thumb {
    background: var(--border);
    border-radius: 10px;
}

.feature-card {
    background-color: var(--card-bg);
    padding: 2.5rem;
    border-radius: 20px;
    border: 1px solid var(--border);
    transition: all 0.3s ease;
    cursor: pointer;
    position: relative;
}

.feature-card:hover {
    transform: translateY(-5px);
    border-color: var(--primary);
    box-shadow: var(--shadow);
}

.feature-card.selected {
    border-color: var(--primary);
    background-color: var(--primary-light);
}

.viewer-container.active .feature-card {
    padding: 1.25rem;
}

.viewer-container.active .feature-card h3 {
    font-size: 1rem;
}

.feature-icon {
    width: 60px;
    height: 60px;
    background-color: var(--primary-light);
    color: var(--primary);
    border-radius: 15px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
}

.viewer-container.active .feature-icon {
    width: 40px;
    height: 40px;
    font-size: 1rem;
    margin-bottom: 0.5rem;
}

/* Preview Panel */
.preview-panel {
    flex: 2;
    background-color: var(--card-bg);
    border-radius: 30px;
    border: 1px solid var(--border);
    padding: 3rem;
    opacity: 0;
    transform: translateX(50px);
    display: none;
    transition: all 0.5s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: var(--shadow);
}

.viewer-container.active .preview-panel {
    display: block;
    opacity: 1;
    transform: translateX(0);
}

.preview-content {
    max-width: 600px;
    margin: 0 auto;
    text-align: center;
}

.preview-icon {
    font-size: 4rem;
    margin-bottom: 1.5rem;
    display: block;
}

.preview-content h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.preview-content p {
    color: var(--text-muted);
    font-size: 1.1rem;
    margin-bottom: 2rem;
}

.preview-content img {
    width: 100%;
    border-radius: 20px;
    margin-bottom: 2rem;
    box-shadow: var(--shadow);
}

/* --- Footer --- */
footer {
    padding: 4rem 0 2rem;
    background-color: var(--bg-alt);
    border-top: 1px solid var(--border);
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 4rem;
    margin-bottom: 4rem;
}

.footer-brand p {
    color: var(--text-muted);
    margin-top: 1rem;
    max-width: 300px;
}

.footer-links h4 {
    margin-bottom: 1.5rem;
}

.footer-links ul li {
    margin-bottom: 0.75rem;
}

.footer-links a {
    color: var(--text-muted);
}

.footer-links a:hover {
    color: var(--primary);
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid var(--border);
    color: var(--text-muted);
    font-size: 0.875rem;
}

/* Mobile Responsiveness */
@media (max-width: 768px) {
    .hero-grid {
        grid-template-columns: 1fr;
        text-align: center;
    }
    .hero-content p {
        margin-inline: auto;
    }
    .hero-actions {
        justify-content: center;
    }
    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background-color: var(--card-bg);
        padding: 2rem;
        flex-direction: column;
        border-bottom: 1px solid var(--border);
        box-shadow: var(--shadow);
        z-index: 1050;
    }

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

    .hamburger {
        display: block;
    }

    .footer-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    .viewer-container.active {
        flex-direction: column;
    }
    .viewer-container.active .features-grid {
        max-width: 100%;
        height: auto;
        display: flex;
        overflow-x: auto;
        padding-bottom: 1rem;
    }

    .desktop-text {
        display: none !important;
    }
    
    .btn-whatsapp {
        padding: 0.75rem 1.5rem;
    }
}