/* ASEAN Power Grid - Main CSS
   Material Design 3 Compliant
   Professional Dark Theme with Split-Complementary Colors */

/* ===========================
   Base & Reset
   =========================== */

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    font-size: var(--md3-body-large);
    line-height: 1.6;
    color: var(--md3-on-background);
    background-color: var(--md3-background);
    overflow-x: hidden;
    position: relative;
}

/* ===========================
   Typography
   =========================== */

h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 1rem;
}

h1 { font-size: var(--md3-display-large); }
h2 { font-size: var(--md3-display-medium); }
h3 { font-size: var(--md3-headline-large); }
h4 { font-size: var(--md3-headline-medium); }
h5 { font-size: var(--md3-headline-small); }
h6 { font-size: var(--md3-body-large); }

p {
    margin-bottom: 1rem;
}

.lead-text {
    font-size: clamp(1.125rem, 2.5vw, 1.375rem);
    line-height: 1.7;
    color: var(--md3-on-surface);
    margin-bottom: 1.5rem;
}

a {
    color: var(--md3-secondary-container);
    text-decoration: none;
    transition: color var(--md3-motion-duration-short) var(--md3-motion-easing-standard);
}

a:hover {
    color: var(--md3-secondary);
}

/* ===========================
   Layout & Grid System
   =========================== */

.container {
    width: 100%;
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 1.25rem;
}

@media (min-width: 768px) {
    .container {
        padding: 0 2.5rem;
    }
}

.section {
    padding: 4rem 0;
    position: relative;
}

@media (min-width: 768px) {
    .section {
        padding: 6rem 0;
    }
}

.section-title {
    text-align: center;
    margin-bottom: 3rem;
    background: linear-gradient(135deg, var(--md3-on-background), var(--md3-on-surface-variant));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.section-content {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

/* Grid Systems */
.advantages-grid,
.industries-grid,
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

@media (min-width: 768px) {
    .industries-grid {
        grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    }
}

/* ===========================
   MD3 Components
   =========================== */

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.875rem 2rem;
    font-size: var(--md3-body-large);
    font-weight: 600;
    text-decoration: none;
    border: none;
    border-radius: var(--md3-corner-extra-small);
    cursor: pointer;
    transition: all var(--md3-motion-duration-medium) var(--md3-motion-easing-standard);
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.2);
    transform: translate(-50%, -50%);
    transition: width 0.6s, height 0.6s;
}

.btn:hover::before {
    width: 300px;
    height: 300px;
}

.btn-primary {
    background: linear-gradient(135deg, var(--md3-secondary), var(--md3-secondary-container));
    color: white;
    box-shadow: 0 2px 8px rgba(255,107,53,0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 16px rgba(255,107,53,0.4);
    color: white;
}

.btn-secondary {
    background: transparent;
    color: var(--md3-secondary);
    border: 2px solid var(--md3-secondary);
}

.btn-secondary:hover {
    background: var(--md3-secondary);
    color: white;
    transform: translateY(-2px);
}

.btn-link {
    display: inline-flex;
    align-items: center;
    color: var(--md3-secondary-container);
    font-weight: 600;
    transition: all var(--md3-motion-duration-short) var(--md3-motion-easing-standard);
}

.btn-link:hover {
    color: var(--md3-secondary);
    transform: translateX(4px);
}

/* Cards - MD3 Elevation System */
.advantage-card,
.industry-card,
.feature {
    background: linear-gradient(0deg, rgba(255,164,71,0.05), rgba(255,164,71,0.05)), var(--md3-surface);
    border-radius: var(--md3-corner-small);
    padding: 2rem;
    transition: all var(--md3-motion-duration-medium) var(--md3-motion-easing-standard);
    border: 1px solid rgba(255,164,71,0.1);
    position: relative;
    overflow: hidden;
}

.advantage-card:hover,
.industry-card:hover,
.feature:hover {
    transform: translateY(-4px);
    background: linear-gradient(0deg, rgba(255,164,71,0.08), rgba(255,164,71,0.08)), var(--md3-surface);
    box-shadow: 0 8px 24px rgba(0,0,0,0.3);
    border-color: rgba(255,164,71,0.2);
}

.advantage-card h3,
.industry-card h3,
.feature h3 {
    color: var(--md3-secondary-container);
    margin-bottom: 0.75rem;
}

/* ===========================
   CSS-Only Icons & Graphics
   =========================== */

.advantage-icon,
.industry-icon {
    width: 60px;
    height: 60px;
    margin-bottom: 1.5rem;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Direct Supply Icon - Arrow */
.advantage-card:nth-child(1) .advantage-icon::before {
    content: '';
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--md3-secondary), var(--md3-secondary-container));
    clip-path: polygon(75% 0%, 100% 50%, 75% 100%, 75% 75%, 0% 75%, 0% 25%, 75% 25%);
}

/* Certified Quality Icon - Badge */
.advantage-card:nth-child(2) .advantage-icon::before {
    content: '';
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--md3-success), #2ECC71);
    clip-path: polygon(50% 0%, 61% 35%, 98% 35%, 68% 57%, 79% 91%, 50% 70%, 21% 91%, 32% 57%, 2% 35%, 39% 35%);
}

/* Proven Product Icon - Checkmark */
.advantage-card:nth-child(3) .advantage-icon::before {
    content: '';
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--md3-secondary), var(--md3-secondary-container));
    border-radius: 50%;
}

.advantage-card:nth-child(3) .advantage-icon::after {
    content: '';
    position: absolute;
    width: 20px;
    height: 10px;
    border-left: 3px solid white;
    border-bottom: 3px solid white;
    transform: rotate(-45deg);
}

/* Professional Packaging Icon - Box */
.advantage-card:nth-child(4) .advantage-icon::before {
    content: '';
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--md3-secondary-container), #FFB74D);
    clip-path: polygon(10% 25%, 50% 5%, 90% 25%, 90% 75%, 50% 95%, 10% 75%);
}

/* Industry Icons */
.steel-icon::before {
    content: '';
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, #FF6B35, #FFA447);
    clip-path: polygon(0% 20%, 30% 0%, 70% 0%, 100% 20%, 100% 80%, 70% 100%, 30% 100%, 0% 80%);
}

.cement-icon::before {
    content: '';
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, #FF8C42, #FFB74D);
    clip-path: polygon(25% 0%, 75% 0%, 100% 50%, 75% 100%, 25% 100%, 0% 50%);
    animation: rotate 20s linear infinite;
}

.glass-icon::before {
    content: '';
    width: 50px;
    height: 45px;
    background: linear-gradient(135deg, rgba(255,164,71,0.3), rgba(255,164,71,0.8));
    clip-path: polygon(20% 0%, 80% 0%, 100% 100%, 0% 100%);
    border: 2px solid var(--md3-secondary-container);
}

.metals-icon::before {
    content: '';
    width: 50px;
    height: 50px;
    background: conic-gradient(from 45deg, #FF6B35, #FFA447, #FFB74D, #FF6B35);
    border-radius: 50%;
    position: relative;
}

.metals-icon::after {
    content: '';
    position: absolute;
    width: 30px;
    height: 30px;
    background: var(--md3-surface);
    border-radius: 50%;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

/* ===========================
   Sections Styling
   =========================== */

/* About Section */
.about-section {
    background: linear-gradient(180deg, transparent, rgba(30,58,95,0.1));
}

/* Advantages Section */
.advantages-section {
    background: 
        radial-gradient(ellipse at 10% 50%, rgba(255,107,53,0.05), transparent 40%),
        var(--md3-background);
}

/* Industries Section */
.industries-section {
    background: linear-gradient(180deg, rgba(30,58,95,0.1), transparent);
}

/* Why Section */
.why-section {
    background: 
        radial-gradient(ellipse at 90% 50%, rgba(255,164,71,0.05), transparent 40%),
        var(--md3-background);
}

/* CTA Section */
.cta-section {
    background: 
        radial-gradient(ellipse at center, rgba(255,107,53,0.1), transparent 60%),
        linear-gradient(135deg, var(--md3-surface), var(--md3-primary-container), var(--md3-surface));
    padding: 5rem 0;
}

.cta-content {
    text-align: center;
}

.cta-content h2 {
    margin-bottom: 2rem;
}

.cta-buttons {
    display: flex;
    gap: 1.5rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* ===========================
   Navigation - Material Design 3
   =========================== */

/* Main Navigation Bar - MD3 Top App Bar */
nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 4rem; /* MD3: 64dp standard height */
    z-index: 1000;
    background: linear-gradient(to bottom, rgba(11, 25, 41, 0.98), rgba(11, 25, 41, 0.95));
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(255, 164, 71, 0.08);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2);
    transition: all var(--md3-motion-duration-medium) var(--md3-motion-easing-standard);
}

/* Container for navigation content */
.nav-container {
    height: 100%;
    display: -webkit-flex; /* Safari */
    display: flex;
    -webkit-align-items: center; /* Safari */
    align-items: center;
    -webkit-justify-content: space-between; /* Safari */
    justify-content: space-between;
    padding: 0 1.5rem; /* MD3: 24dp horizontal padding */
}

/* Logo/Brand - MD3 Title Large */
.logo {
    font-size: 1.375rem; /* MD3: Title Large (22sp) */
    font-weight: 600;
    color: var(--md3-on-surface);
    text-decoration: none;
    letter-spacing: -0.01em;
    transition: all var(--md3-motion-duration-short) var(--md3-motion-easing-standard);
    display: -webkit-inline-flex; /* Safari */
    display: inline-flex;
    -webkit-align-items: center; /* Safari */
    align-items: center;
    height: 2.5rem;
    padding: 0 0.75rem;
    border-radius: var(--md3-corner-extra-small);
    position: relative;
    -webkit-flex-shrink: 0; /* Safari */
    flex-shrink: 0;
}

.logo::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--md3-secondary);
    opacity: 0;
    border-radius: var(--md3-corner-extra-small);
    transition: opacity var(--md3-motion-duration-short) var(--md3-motion-easing-standard);
}

.logo:hover::before {
    opacity: 0.08;
}

.logo:hover {
    color: var(--md3-secondary-container);
}

/* Navigation Menu - MD3 Navigation Rail Pattern */
.nav-menu {
    display: -webkit-flex; /* Safari */
    display: flex;
    -webkit-flex-direction: row; /* Safari explicit */
    flex-direction: row;
    list-style: none;
    gap: 0.5rem; /* MD3: 8dp between items */
    margin: 0;
    padding: 0;
    -webkit-align-items: center; /* Safari */
    align-items: center;
    height: 100%;
    -webkit-flex-shrink: 0; /* Safari */
    flex-shrink: 0;
}

.nav-menu li {
    margin: 0;
    padding: 0;
    height: 100%;
    display: -webkit-flex; /* Safari */
    display: flex;
    -webkit-align-items: center; /* Safari */
    align-items: center;
    -webkit-flex-shrink: 0; /* Safari */
    flex-shrink: 0;
}

/* Navigation Links - MD3 Label Large with States */
.nav-link {
    color: var(--md3-on-surface-variant);
    text-decoration: none;
    font-size: 0.9375rem; /* MD3: Label Large (14sp) */
    font-weight: 500;
    letter-spacing: 0.01em;
    padding: 0.625rem 1rem; /* MD3: 10dp vertical, 16dp horizontal */
    height: 2.5rem;
    display: -webkit-inline-flex; /* Safari */
    display: inline-flex;
    -webkit-align-items: center; /* Safari */
    align-items: center;
    -webkit-justify-content: center; /* Safari */
    justify-content: center;
    border-radius: var(--md3-corner-extra-small);
    position: relative;
    transition: all var(--md3-motion-duration-short) var(--md3-motion-easing-standard);
    white-space: nowrap;
    -webkit-flex-shrink: 0; /* Safari */
    flex-shrink: 0;
}

/* Hover State Indicator */
.nav-link::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--md3-secondary);
    opacity: 0;
    border-radius: var(--md3-corner-extra-small);
    transition: opacity var(--md3-motion-duration-short) var(--md3-motion-easing-standard);
}

.nav-link:hover::before {
    opacity: 0.08;
}

.nav-link:hover {
    color: var(--md3-secondary-container);
}

/* Active/Current Page Indicator */
.nav-link.active {
    color: var(--md3-secondary-container);
    font-weight: 600;
}

.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: calc(100% - 2rem);
    height: 3px;
    background: var(--md3-secondary);
    border-radius: 3px 3px 0 0;
}

/* Mobile Menu Toggle - MD3 Icon Button */
.mobile-menu-toggle {
    display: none;
    width: 2.5rem;
    height: 2.5rem;
    background: transparent;
    border: none;
    border-radius: var(--md3-corner-extra-small);
    color: var(--md3-on-surface);
    font-size: 1.5rem;
    cursor: pointer;
    transition: all var(--md3-motion-duration-short) var(--md3-motion-easing-standard);
    position: relative;
    -webkit-align-items: center; /* Safari */
    align-items: center;
    -webkit-justify-content: center; /* Safari */
    justify-content: center;
    -webkit-flex-shrink: 0; /* Safari */
    flex-shrink: 0;
}

.mobile-menu-toggle::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--md3-on-surface);
    opacity: 0;
    border-radius: var(--md3-corner-extra-small);
    transition: opacity var(--md3-motion-duration-short) var(--md3-motion-easing-standard);
}

.mobile-menu-toggle:hover::before {
    opacity: 0.08;
}

.mobile-menu-toggle:active::before {
    opacity: 0.12;
}

/* Mobile Menu Styles */
@media (max-width: 768px) {
    .nav-container {
        padding: 0 1rem; /* MD3: 16dp on mobile */
    }
    
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 4rem; /* Height of nav bar */
        -webkit-flex-direction: column; /* Safari */
        flex-direction: column;
        background: linear-gradient(to bottom, var(--md3-surface), rgba(11, 25, 41, 0.98));
        width: 100%;
        height: calc(100vh - 4rem);
        text-align: center;
        transition: left var(--md3-motion-duration-medium) var(--md3-motion-easing-standard);
        padding: 1rem 0;
        gap: 0.25rem;
        box-shadow: 0 4px 8px rgba(0, 0, 0, 0.3);
        overflow-y: auto;
        -webkit-overflow-scrolling: touch; /* Safari smooth scrolling */
        -webkit-justify-content: flex-start; /* Safari */
        justify-content: flex-start;
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .nav-menu li {
        width: 100%;
        height: auto;
    }
    
    .nav-link {
        width: calc(100% - 2rem);
        margin: 0 1rem;
        padding: 1rem;
        height: auto;
        justify-content: center;
        font-size: 1rem;
    }
    
    .nav-link.active::after {
        display: none;
    }
    
    .nav-link.active {
        background: rgba(255, 107, 53, 0.1);
    }
    
    .mobile-menu-toggle {
        display: -webkit-flex; /* Safari */
        display: flex;
    }
}

/* Tablet Adjustments */
@media (min-width: 769px) and (max-width: 1024px) {
    .nav-container {
        padding: 0 1.25rem;
    }
    
    .nav-menu {
        gap: 0.25rem;
    }
    
    .nav-link {
        padding: 0.625rem 0.875rem;
        font-size: 0.875rem;
    }
}

/* Enhanced scroll behavior */
body {
    padding-top: 4rem; /* Compensate for fixed nav */
}

/* Navigation scroll effect */
nav.scrolled {
    background: rgba(11, 25, 41, 1);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

/* Skip navigation for accessibility */
.skip-nav {
    position: absolute;
    top: -100px;
    left: 0;
    background: var(--md3-secondary);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: var(--md3-corner-extra-small);
    text-decoration: none;
    z-index: 1001;
}

.skip-nav:focus {
    top: 0.5rem;
    left: 0.5rem;
}

/* ===========================
   Footer
   =========================== */

.footer {
    background: var(--md3-surface);
    border-top: 1px solid rgba(255,164,71,0.1);
    padding: 3rem 0 2rem;
    margin-top: 4rem;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-column h4 {
    color: var(--md3-secondary-container);
    margin-bottom: 1rem;
    font-size: var(--md3-headline-small);
}

.footer-column ul {
    list-style: none;
}

.footer-column li {
    margin-bottom: 0.5rem;
}

.footer-column a {
    color: var(--md3-on-surface-variant);
    transition: color var(--md3-motion-duration-short) var(--md3-motion-easing-standard);
}

.footer-column a:hover {
    color: var(--md3-secondary-container);
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(255,164,71,0.05);
    color: var(--md3-on-surface-variant);
}

/* ===========================
   Animations
   =========================== */

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes rotate {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

.animate-in {
    animation: fadeInUp 0.8s var(--md3-motion-easing-standard) forwards;
    opacity: 0;
}

/* ===========================
   Responsive Design
   =========================== */

@media (max-width: 768px) {
    h1 { font-size: clamp(2rem, 8vw, 3rem); }
    h2 { font-size: clamp(1.5rem, 6vw, 2.5rem); }
    
    .section {
        padding: 3rem 0;
    }
    
    .advantages-grid,
    .industries-grid,
    .features-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .cta-buttons {
        flex-direction: column;
        align-items: stretch;
    }
    
    .footer-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 480px) {
    .footer-grid {
        grid-template-columns: 1fr;
    }
}

/* ===========================
   Accessibility
   =========================== */

:focus-visible {
    outline: 2px solid var(--md3-secondary-container);
    outline-offset: 2px;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    .btn,
    .advantage-card,
    .industry-card,
    .feature {
        border: 2px solid currentColor;
    }
}

/* Reduced motion support */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
}

/* ===========================
   Loading States
   =========================== */

.skeleton {
    background: linear-gradient(
        90deg,
        rgba(255,164,71,0.1) 25%,
        rgba(255,164,71,0.2) 50%,
        rgba(255,164,71,0.1) 75%
    );
    background-size: 200% 100%;
    animation: loading 1.5s infinite;
}

@keyframes loading {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}

/* ===========================
   Print Styles
   =========================== */

@media print {
    nav,
    .cta-section,
    .footer {
        display: none;
    }
    
    body {
        color: black;
        background: white;
    }
    
    a {
        color: black;
        text-decoration: underline;
    }
}