/**
 * ============================================================================
 * UNIVERSAL RESPONSIVE DESIGN SYSTEM - COMPLETE
 * Optimized for ALL screen sizes and devices (320px to 4K displays)
 * ============================================================================
 */

/* ============================================================================
   BASE RESPONSIVE FOUNDATION
   ============================================================================ */

* {
    box-sizing: border-box;
}

html {
    font-size: 16px;
    -webkit-text-size-adjust: 100%;
    -moz-text-size-adjust: 100%;
    -ms-text-size-adjust: 100%;
    text-size-adjust: 100%;
}

body {
    overflow-x: hidden;
    width: 100%;
    min-height: 100vh;
}

img, video, iframe, embed, object {
    max-width: 100%;
    height: auto;
}

pre, code, .code-block {
    max-width: 100%;
    overflow-x: auto;
    word-wrap: break-word;
}

/* ============================================================================
   CONTAINER SYSTEM
   ============================================================================ */

.container, .dashboard-container {
    width: 100%;
    margin-left: auto;
    margin-right: auto;
    padding-left: 1rem;
    padding-right: 1rem;
}

@media (min-width: 480px) {
    .container { 
        padding-left: 1.5rem;
        padding-right: 1.5rem;
    }
}

@media (min-width: 768px) { .container { max-width: 720px; } }
@media (min-width: 1024px) { .container { max-width: 960px; } }
@media (min-width: 1280px) { .container { max-width: 1140px; } }
@media (min-width: 1920px) { .container { max-width: 1600px; } }

/* ============================================================================
   TYPOGRAPHY SCALING
   ============================================================================ */

@media (max-width: 479px) {
    html { font-size: 14px; }
    h1, .hero-title { font-size: 1.75rem !important; line-height: 1.2; }
    h2, .section-title { font-size: 1.5rem !important; }
    h3 { font-size: 1.25rem !important; }
    h4 { font-size: 1.1rem !important; }
    body { font-size: 0.875rem; line-height: 1.5; }
}

@media (min-width: 480px) and (max-width: 767px) {
    html { font-size: 15px; }
    h1, .hero-title { font-size: 2rem !important; }
    h2, .section-title { font-size: 1.75rem !important; }
}

@media (min-width: 768px) and (max-width: 1023px) {
    h1, .hero-title { font-size: 2.5rem !important; }
    h2, .section-title { font-size: 2rem !important; }
}

/* ============================================================================
   NAVIGATION
   ============================================================================ */

@media (max-width: 767px) {
    .navbar, .dashboard-nav {
        position: sticky;
        top: 0;
        width: 100%;
        margin: 0;
        border-radius: 0;
        padding: 0.75rem 1rem;
        z-index: 1000;
    }
    
    .nav-logo {
        gap: 0.5rem;
        font-size: 1.1rem;
    }
    
    .logo-img {
        width: 40px;
        height: 40px;
    }
    
    .nav-links {
        display: none;
        position: fixed;
        top: 60px;
        left: 0;
        width: 100%;
        max-width: 320px;
        height: calc(100vh - 60px);
        background: var(--bg-secondary, rgba(15, 23, 42, 0.98));
        backdrop-filter: blur(20px);
        flex-direction: column;
        padding: 1.5rem 1rem;
        overflow-y: auto;
        box-shadow: 4px 0 20px rgba(0, 0, 0, 0.5);
        transform: translateX(-100%);
        transition: transform 0.3s ease;
        z-index: 999;
    }
    
    .nav-links.active, .nav-links.mobile-open {
        display: flex;
        transform: translateX(0);
    }
    
    .nav-links li {
        width: 100%;
        margin: 0;
    }
    
    .nav-links a, .nav-link {
        display: block;
        width: 100%;
        padding: 1rem 1.25rem;
        border-radius: 0.5rem;
        margin-bottom: 0.5rem;
    }
    
    .mobile-menu-btn, .hamburger-menu {
        display: flex !important;
        flex-direction: column;
        justify-content: space-between;
        width: 32px;
        height: 26px;
        background: transparent;
        border: none;
        cursor: pointer;
        padding: 0;
    }
    
    .mobile-menu-btn span, .hamburger-menu .line {
        width: 100%;
        height: 3px;
        background: var(--text-primary, #fff);
        border-radius: 3px;
        transition: all 0.3s ease;
    }
    
    .mobile-menu-btn.active span:nth-child(1),
    .hamburger-menu.active .line:nth-child(1) {
        transform: rotate(45deg) translateY(11px);
    }
    
    .mobile-menu-btn.active span:nth-child(2),
    .hamburger-menu.active .line:nth-child(2) {
        opacity: 0;
    }
    
    .mobile-menu-btn.active span:nth-child(3),
    .hamburger-menu.active .line:nth-child(3) {
        transform: rotate(-45deg) translateY(-11px);
    }
    
    body.nav-open::before {
        content: '';
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        background: rgba(0, 0, 0, 0.5);
        z-index: 998;
    }
}

@media (min-width: 768px) {
    .mobile-menu-btn, .hamburger-menu {
        display: none !important;
    }
    
    .navbar {
        top: 1rem;
        width: calc(100% - 2rem);
        max-width: 1200px;
        margin: 1rem auto;
    }
}

/* ============================================================================
   HERO SECTION
   ============================================================================ */

@media (max-width: 767px) {
    .hero-section {
        min-height: auto;
        padding-top: 80px;
        padding-bottom: 2rem;
    }
    
    .hero-section .container {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .hero-content {
        text-align: center;
        padding-top: 1rem;
    }
    
    .hero-badge {
        margin: 0 auto 1.5rem;
        padding: 0.65rem 1rem;
        max-width: 100%;
    }
    
    .badge-text {
        font-size: 0.7rem;
        white-space: normal;
        text-align: center;
        line-height: 1.3;
    }
    
    .hero-buttons {
        flex-direction: column;
        gap: 0.75rem;
        width: 100%;
        margin-bottom: 2rem;
    }
    
    .hero-buttons .btn {
        width: 100%;
        padding: 1rem 1.5rem;
    }
    
    .hero-stats {
        grid-template-columns: repeat(2, 1fr);
        gap: 0.75rem;
    }
    
    .stat-item {
        padding: 0.75rem;
    }
    
    .stat-number {
        font-size: 1.5rem;
    }
    
    .stat-label {
        font-size: 0.75rem;
    }
    
    .hero-logo-container, .hero-image {
        max-width: 280px;
        height: 280px;
        margin: 1rem auto 0;
    }
}

@media (max-width: 479px) {
    .hero-stats {
        grid-template-columns: 1fr;
        gap: 0.5rem;
    }
}

@media (min-width: 768px) and (max-width: 1023px) {
    .hero-section .container {
        grid-template-columns: 1fr;
        gap: 3rem;
        text-align: center;
    }
    
    .hero-stats {
        grid-template-columns: repeat(3, 1fr);
        max-width: 100%;
    }
    
    .hero-logo-container {
        max-width: 400px;
        height: 400px;
    }
}

@media (min-width: 1024px) {
    .hero-section .container {
        grid-template-columns: 1.2fr 1fr;
        align-items: center;
    }
    
    .hero-stats {
        grid-template-columns: repeat(5, 1fr);
    }
}

/* ============================================================================
   GRID LAYOUTS
   ============================================================================ */

@media (max-width: 479px) {
    .features-grid, .why-choose-grid, .tech-features, .facilities-grid,
    .academics-grid, .contact-grid, .download-grid, .about-highlights,
    .achievements-grid, .placement-stats, .dashboard-widgets,
    .quick-stats, .stats-grid {
        grid-template-columns: 1fr !important;
        gap: 1rem;
    }
}

@media (min-width: 480px) and (max-width: 767px) {
    .features-grid, .why-choose-grid, .tech-features, .facilities-grid {
        grid-template-columns: 1fr;
        gap: 1.25rem;
    }
    
    .academics-grid, .contact-grid, .about-highlights {
        grid-template-columns: repeat(2, 1fr);
        gap: 1rem;
    }
}

@media (min-width: 768px) and (max-width: 1023px) {
    .features-grid, .why-choose-grid, .tech-features, .facilities-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 1.5rem;
    }
    
    .academics-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 1.5rem;
    }
}

@media (min-width: 1024px) and (max-width: 1279px) {
    .features-grid, .academics-grid, .why-choose-grid, .tech-features {
        grid-template-columns: repeat(3, 1fr);
    }
    
    .facilities-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

@media (min-width: 1280px) {
    .features-grid, .academics-grid {
        grid-template-columns: repeat(3, 1fr);
    }
    
    .facilities-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

@media (min-width: 1920px) {
    .features-grid, .academics-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

/* ============================================================================
   CARDS
   ============================================================================ */

@media (max-width: 767px) {
    .feature-card, .why-card, .tech-feature-item, .facility-card,
    .academic-card, .contact-card, .download-card, .glass-card {
        padding: 1.25rem;
    }
    
    .feature-icon, .why-icon, .tech-icon, .facility-icon,
    .academic-icon, .contact-icon, .download-icon {
        font-size: 2rem;
        margin-bottom: 1rem;
    }
    
    .widget, .dashboard-section {
        padding: 1.25rem;
        margin-bottom: 1rem;
    }
}

@media (min-width: 768px) {
    .feature-card, .why-card, .tech-feature-item {
        padding: 1.5rem;
    }
    
    .academic-card, .facility-card {
        padding: 2rem;
    }
}

/* ============================================================================
   DASHBOARD
   ============================================================================ */

@media (max-width: 767px) {
    .dashboard-main {
        padding: 1rem;
        padding-bottom: 90px;
    }
    
    .dashboard-welcome {
        padding: 1.5rem;
        margin-bottom: 1.5rem;
    }
    
    .dashboard-welcome h2 {
        font-size: 1.5rem;
    }
    
    .quick-stats {
        grid-template-columns: 1fr;
        gap: 1rem;
        padding: 1rem;
    }
    
    .stat-card {
        padding: 1.25rem;
    }
    
    .stat-value {
        font-size: 2rem;
    }
    
    .dashboard-widgets {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .mobile-bottom-nav {
        display: flex;
        position: fixed;
        bottom: 0;
        left: 0;
        right: 0;
        height: 70px;
        background: rgba(15, 23, 42, 0.98);
        backdrop-filter: blur(20px);
        border-top: 1px solid rgba(255, 255, 255, 0.1);
        box-shadow: 0 -4px 20px rgba(0, 0, 0, 0.5);
        justify-content: space-around;
        align-items: center;
        z-index: 1000;
    }
    
    .mobile-bottom-nav .nav-item {
        display: flex;
        flex-direction: column;
        align-items: center;
        justify-content: center;
        flex: 1;
        min-height: 56px;
        text-decoration: none;
        color: rgba(255, 255, 255, 0.6);
        transition: all 0.3s ease;
        padding: 0.5rem;
        border-radius: 0.75rem;
        margin: 0 0.25rem;
    }
    
    .mobile-bottom-nav .nav-item .icon {
        font-size: 1.5rem;
        margin-bottom: 0.25rem;
    }
    
    .mobile-bottom-nav .nav-item span {
        font-size: 0.7rem;
        font-weight: 600;
    }
    
    .mobile-bottom-nav .nav-item.active {
        color: var(--primary, #6366f1);
        background: rgba(99, 102, 241, 0.1);
    }
}

@media (min-width: 768px) and (max-width: 1023px) {
    .quick-stats {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .dashboard-widgets {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .mobile-bottom-nav {
        display: none;
    }
}

@media (min-width: 1024px) {
    .quick-stats {
        grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    }
    
    .dashboard-widgets {
        grid-template-columns: repeat(3, 1fr);
    }
    
    .mobile-bottom-nav {
        display: none;
    }
}

/* ============================================================================
   FORMS
   ============================================================================ */

@media (max-width: 767px) {
    .form-row, .form-grid {
        grid-template-columns: 1fr !important;
        gap: 1rem;
    }
    
    .form-group {
        margin-bottom: 1rem;
    }
    
    .form-group input, .form-group select, .form-group textarea {
        font-size: 16px;
        padding: 0.875rem;
        width: 100%;
    }
    
    .login-card, .register-card {
        padding: 1.5rem;
        margin: 1rem;
    }
    
    .demo-accounts-mini {
        flex-direction: column;
        gap: 0.5rem;
    }
    
    .demo-item {
        width: 100%;
    }
    
    .role-selection {
        flex-direction: column;
        gap: 0.75rem;
    }
}

@media (min-width: 768px) {
    .form-row {
        grid-template-columns: repeat(2, 1fr);
        gap: 1.5rem;
    }
}

/* ============================================================================
   TABLES
   ============================================================================ */

@media (max-width: 767px) {
    .table-responsive {
        overflow-x: auto;
        -webkit-overflow-scrolling: touch;
    }
    
    .data-table {
        min-width: 600px;
        font-size: 0.85rem;
    }
    
    .data-table th, .data-table td {
        padding: 0.75rem 0.5rem;
        white-space: nowrap;
    }
}

@media (max-width: 479px) {
    .data-table-stacked table,
    .data-table-stacked thead,
    .data-table-stacked tbody,
    .data-table-stacked th,
    .data-table-stacked td,
    .data-table-stacked tr {
        display: block;
        width: 100%;
    }
    
    .data-table-stacked thead tr {
        position: absolute;
        top: -9999px;
        left: -9999px;
    }
    
    .data-table-stacked tr {
        border: 1px solid var(--glass-border, #e2e8f0);
        margin-bottom: 1rem;
        border-radius: 0.5rem;
        padding: 1rem;
        background: var(--glass-bg, rgba(255, 255, 255, 0.05));
    }
    
    .data-table-stacked td {
        border: none;
        position: relative;
        padding-left: 50%;
        text-align: right;
        min-height: 40px;
        padding-top: 0.75rem;
        padding-bottom: 0.75rem;
    }
    
    .data-table-stacked td::before {
        content: attr(data-label);
        position: absolute;
        left: 0;
        font-weight: 600;
        text-align: left;
    }
}

/* ============================================================================
   BUTTONS
   ============================================================================ */

@media (max-width: 767px) {
    button, .btn, a.btn,
    input[type="button"],
    input[type="submit"] {
        min-height: 44px;
        min-width: 44px;
        font-size: 16px;
        padding: 0.75rem 1.25rem;
    }
    
    .btn-large {
        padding: 1rem 1.5rem;
        font-size: 1.1rem;
    }
    
    .btn-sm {
        min-height: 36px;
        padding: 0.5rem 1rem;
        font-size: 0.875rem;
    }
    
    .action-btns {
        flex-direction: column;
        gap: 0.5rem;
    }
    
    .action-btns .btn {
        width: 100%;
    }
}

/* ============================================================================
   SECTIONS
   ============================================================================ */

@media (max-width: 767px) {
    .features-section, .download-section, .about-section,
    .academics-section, .contact-section, .why-choose-section,
    .tech-stack-section, .facilities-section, .placement-section {
        padding: 2rem 0;
        margin: 1.5rem 0;
    }
    
    .section-header {
        margin-bottom: 1.5rem;
    }
    
    .about-highlights, .vision-mission {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .recruiters-grid {
        gap: 0.5rem;
    }
    
    .recruiter-tag {
        padding: 0.5rem 1rem;
        font-size: 0.85rem;
    }
}

@media (min-width: 768px) and (max-width: 1023px) {
    .about-highlights {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* ============================================================================
   FOOTER
   ============================================================================ */

@media (max-width: 767px) {
    .footer {
        padding: 2rem 0 1rem;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
}

@media (min-width: 768px) and (max-width: 1023px) {
    .footer-content {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .footer-content {
        grid-template-columns: repeat(4, 1fr);
    }
}

/* ============================================================================
   FLOATING BUTTONS
   ============================================================================ */

@media (max-width: 767px) {
    .theme-toggle {
        bottom: 90px;
        right: 20px;
        width: 48px;
        height: 48px;
    }
}

@media (min-width: 768px) {
    .theme-toggle {
        bottom: 24px;
        right: 96px;
    }
}

/* ============================================================================
   LANDSCAPE MODE
   ============================================================================ */

@media (max-width: 900px) and (orientation: landscape) {
    .hero-section {
        min-height: auto;
        padding: 2rem 0;
    }
    
    .hero-section .container {
        grid-template-columns: 1fr 1fr;
        gap: 2rem;
    }
    
    .hero-stats {
        grid-template-columns: repeat(5, 1fr);
    }
    
    .mobile-bottom-nav {
        height: 56px;
    }
    
    .mobile-bottom-nav .nav-item span {
        display: none;
    }
}

/* ============================================================================
   MODALS
   ============================================================================ */

@media (max-width: 767px) {
    .modal, .dialog, .popup {
        max-width: 100%;
        margin: 0;
        border-radius: 1rem 1rem 0 0;
        position: fixed;
        bottom: 0;
        left: 0;
        right: 0;
        max-height: 90vh;
        overflow-y: auto;
    }
    
    .modal-header {
        position: sticky;
        top: 0;
        background: var(--bg-secondary, #1e293b);
        z-index: 10;
        padding-top: 1.5rem;
    }
    
    .modal-header::before {
        content: '';
        position: absolute;
        top: 0.5rem;
        left: 50%;
        transform: translateX(-50%);
        width: 40px;
        height: 4px;
        background: var(--text-muted, #94a3b8);
        border-radius: 2px;
    }
}

/* ============================================================================
   SAFE AREA INSETS
   ============================================================================ */

@supports (padding: env(safe-area-inset-bottom)) {
    body {
        padding-top: env(safe-area-inset-top);
        padding-left: env(safe-area-inset-left);
        padding-right: env(safe-area-inset-right);
    }
    
    .navbar, .dashboard-nav {
        padding-left: calc(1rem + env(safe-area-inset-left));
        padding-right: calc(1rem + env(safe-area-inset-right));
    }
    
    @media (max-width: 767px) {
        .dashboard-main {
            padding-bottom: calc(90px + env(safe-area-inset-bottom));
        }
        
        .mobile-bottom-nav {
            padding-bottom: env(safe-area-inset-bottom);
            height: calc(70px + env(safe-area-inset-bottom));
        }
    }
}

/* ============================================================================
   UTILITY CLASSES
   ============================================================================ */

@media (max-width: 479px) {
    .hide-xs { display: none !important; }
    .show-xs { display: block !important; }
    .text-center-xs { text-align: center !important; }
    .w-100-xs { width: 100% !important; }
}

@media (min-width: 480px) and (max-width: 767px) {
    .hide-sm { display: none !important; }
    .show-sm { display: block !important; }
    .text-center-sm { text-align: center !important; }
}

@media (min-width: 768px) and (max-width: 1023px) {
    .hide-md { display: none !important; }
    .show-md { display: block !important; }
}

@media (min-width: 1024px) {
    .hide-lg { display: none !important; }
    .show-lg { display: block !important; }
}

@media (max-width: 767px) {
    .hide-mobile { display: none !important; }
    .show-mobile { display: block !important; }
    .flex-column-mobile { flex-direction: column !important; }
    .w-100-mobile { width: 100% !important; }
    .text-center-mobile { text-align: center !important; }
    .p-mobile-sm { padding: 0.5rem !important; }
    .p-mobile-md { padding: 1rem !important; }
    .m-mobile-sm { margin: 0.5rem !important; }
    .m-mobile-md { margin: 1rem !important; }
}

@media (min-width: 768px) {
    .show-mobile { display: none !important; }
    .hide-desktop { display: none !important; }
}

/* ============================================================================
   PRINT STYLES
   ============================================================================ */

@media print {
    .navbar, .theme-toggle, .mobile-bottom-nav,
    .mobile-menu-btn, .bg-animation, .hero-buttons,
    footer, .fab, .floating-action-btn {
        display: none !important;
    }
    
    body {
        background: white;
        color: black;
    }
    
    .glass-card {
        border: 1px solid #ddd;
        box-shadow: none;
    }
}

/* ============================================================================
   REDUCED MOTION
   ============================================================================ */

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    
    .gradient-orb {
        animation: none !important;
    }
}

/* ============================================================================
   HIGH CONTRAST MODE
   ============================================================================ */

@media (prefers-contrast: high) {
    .glass-card {
        border: 2px solid currentColor;
    }
    
    .btn {
        border: 2px solid currentColor;
    }
}

/* ============================================================================
   DARK MODE SUPPORT
   ============================================================================ */

@media (prefers-color-scheme: dark) {
    :root {
        color-scheme: dark;
    }
}

/* ============================================================================
   END OF RESPONSIVE UNIVERSAL CSS
   ============================================================================ */