/* ===== CSS Variables ===== */
:root {
    --orange-primary: #FF6B00;
    --orange-light: #FF8533;
    --orange-dark: #E55A00;
    --orange-glow: rgba(255, 107, 0, 0.2);
    
    --gray-900: #1A1A1A;
    --gray-800: #2D2D2D;
    --gray-700: #3D3D3D;
    --gray-600: #4D4D4D;
    --gray-500: #6B6B6B;
    --gray-400: #8B8B8B;
    --gray-300: #ABABAB;
    --gray-200: #D4D4D4;
    --gray-100: #F5F5F5;
    
    --white: #FFFFFF;
    --black: #000000;
    
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.15);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.2);
    --shadow-xl: 0 20px 40px rgba(0, 0, 0, 0.25);
    
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    
    --transition: all 0.3s ease;
}

/* ===== Reset & Base ===== */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    font-size: 16px;
    line-height: 1.6;
    color: var(--gray-200);
    background-color: var(--gray-900);
}

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

ul, ol {
    list-style: none;
}

img {
    max-width: 100%;
    height: auto;
}

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    background: none;
}

/* ===== Container ===== */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* ===== Header ===== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(26, 26, 26, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--gray-700);
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo-icon {
    font-size: 28px;
}

.logo-text {
    font-size: 24px;
    font-weight: 700;
    color: var(--orange-primary);
    letter-spacing: 1px;
}

.nav {
    display: flex;
    gap: 30px;
}

.nav a {
    font-size: 15px;
    font-weight: 500;
    color: var(--gray-300);
    padding: 8px 0;
    position: relative;
}

.nav a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--orange-primary);
    transition: var(--transition);
}

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

.nav a:hover::after {
    width: 100%;
}

.mobile-menu-btn {
    display: none;
    flex-direction: column;
    gap: 5px;
    padding: 5px;
}

.mobile-menu-btn span {
    display: block;
    width: 25px;
    height: 2px;
    background: var(--gray-200);
    transition: var(--transition);
}

.mobile-nav {
    display: none;
    position: fixed;
    top: 70px;
    left: 0;
    right: 0;
    background: var(--gray-800);
    padding: 20px;
    flex-direction: column;
    gap: 15px;
    z-index: 999;
    border-bottom: 1px solid var(--gray-700);
}

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

.mobile-nav a {
    font-size: 16px;
    color: var(--gray-200);
    padding: 10px 0;
    border-bottom: 1px solid var(--gray-700);
}

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

/* ===== Sections ===== */
.section {
    padding: 100px 0;
}

.section:first-of-type {
    padding-top: 150px;
}

.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-header h1,
.section-header h2 {
    font-size: 36px;
    font-weight: 700;
    color: var(--white);
    margin-bottom: 20px;
}

.divider {
    width: 80px;
    height: 4px;
    background: linear-gradient(90deg, var(--orange-primary), var(--orange-light));
    margin: 0 auto 20px;
    border-radius: 2px;
}

.section-subtitle {
    font-size: 18px;
    color: var(--gray-400);
    max-width: 700px;
    margin: 0 auto;
}

/* ===== Intro Section ===== */
.section-intro {
    background: linear-gradient(180deg, var(--gray-900) 0%, var(--gray-800) 100%);
}

.intro-content {
    display: grid;
    gap: 60px;
}

.intro-text .lead {
    font-size: 20px;
    color: var(--gray-100);
    margin-bottom: 20px;
    line-height: 1.7;
}

.intro-text p {
    color: var(--gray-300);
    margin-bottom: 15px;
}

.intro-features {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
}

.feature-card {
    background: var(--gray-800);
    border: 1px solid var(--gray-700);
    border-radius: var(--radius-lg);
    padding: 30px 20px;
    text-align: center;
    transition: var(--transition);
}

.feature-card:hover {
    border-color: var(--orange-primary);
    transform: translateY(-5px);
    box-shadow: 0 10px 30px var(--orange-glow);
}

.feature-icon {
    font-size: 40px;
    margin-bottom: 15px;
}

.feature-card h3 {
    font-size: 16px;
    font-weight: 600;
    color: var(--white);
    margin-bottom: 5px;
}

.feature-card p {
    font-size: 14px;
    color: var(--gray-400);
}

/* ===== Functions Section ===== */
.section-functions {
    background: var(--gray-800);
}

.functions-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    margin-bottom: 50px;
}

.function-card {
    background: var(--gray-900);
    border: 1px solid var(--gray-700);
    border-radius: var(--radius-lg);
    padding: 30px;
    transition: var(--transition);
    position: relative;
}

.function-card:hover {
    border-color: var(--orange-primary);
    box-shadow: var(--shadow-lg);
}

.function-number {
    position: absolute;
    top: -15px;
    left: 20px;
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--orange-primary), var(--orange-dark));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    font-weight: 700;
    color: var(--white);
}

.function-card h3 {
    font-size: 18px;
    font-weight: 600;
    color: var(--white);
    margin-bottom: 15px;
    padding-top: 10px;
}

.function-card > p {
    color: var(--gray-300);
    margin-bottom: 15px;
    font-size: 15px;
}

.function-card ul {
    padding-left: 0;
}

.function-card ul li {
    position: relative;
    padding-left: 20px;
    margin-bottom: 8px;
    color: var(--gray-400);
    font-size: 14px;
}

.function-card ul li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 8px;
    width: 6px;
    height: 6px;
    background: var(--orange-primary);
    border-radius: 50%;
}

.summary-box {
    background: linear-gradient(135deg, var(--orange-primary), var(--orange-dark));
    border-radius: var(--radius-lg);
    padding: 30px 40px;
    text-align: center;
}

.summary-box h4 {
    font-size: 20px;
    font-weight: 600;
    color: var(--white);
    margin-bottom: 10px;
}

.summary-box p {
    color: rgba(255, 255, 255, 0.9);
    font-size: 16px;
    max-width: 800px;
    margin: 0 auto;
}

/* ===== Mandatory Section ===== */
.section-mandatory {
    background: var(--gray-900);
}

.mandatory-alert {
    display: flex;
    align-items: flex-start;
    gap: 20px;
    background: linear-gradient(135deg, rgba(255, 107, 0, 0.15), rgba(255, 107, 0, 0.05));
    border: 1px solid var(--orange-primary);
    border-radius: var(--radius-lg);
    padding: 30px;
    margin-bottom: 50px;
}

.alert-icon {
    font-size: 40px;
    flex-shrink: 0;
}

.alert-text strong {
    display: block;
    font-size: 24px;
    color: var(--orange-primary);
    margin-bottom: 10px;
}

.alert-text p {
    color: var(--gray-200);
    font-size: 16px;
}

.mandatory-content h3 {
    font-size: 24px;
    font-weight: 600;
    color: var(--white);
    margin-bottom: 30px;
    text-align: center;
}

.timeline {
    max-width: 800px;
    margin: 0 auto;
}

.timeline-item {
    display: flex;
    gap: 20px;
    padding: 25px;
    background: var(--gray-800);
    border: 1px solid var(--gray-700);
    border-radius: var(--radius-lg);
    margin-bottom: 20px;
    transition: var(--transition);
}

.timeline-item:hover {
    border-color: var(--orange-primary);
}

.timeline-item.warning {
    border-color: var(--orange-dark);
    background: linear-gradient(135deg, rgba(255, 107, 0, 0.1), transparent);
}

.timeline-icon {
    font-size: 32px;
    flex-shrink: 0;
}

.timeline-content h4 {
    font-size: 18px;
    font-weight: 600;
    color: var(--white);
    margin-bottom: 10px;
}

.timeline-content p {
    color: var(--gray-300);
    font-size: 15px;
}

.timeline-content strong {
    color: var(--orange-primary);
}

/* ===== Changes Section ===== */
.section-changes {
    background: var(--gray-800);
}

.changes-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 30px;
}

.change-card {
    background: var(--gray-900);
    border: 1px solid var(--gray-700);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: var(--transition);
}

.change-card:hover {
    border-color: var(--orange-primary);
    box-shadow: var(--shadow-lg);
}

.change-header {
    display: flex;
    align-items: center;
    gap: 15px;
    padding: 20px 25px;
    background: var(--gray-800);
    border-bottom: 1px solid var(--gray-700);
}

.change-number {
    width: 35px;
    height: 35px;
    background: linear-gradient(135deg, var(--orange-primary), var(--orange-dark));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 16px;
    font-weight: 700;
    color: var(--white);
    flex-shrink: 0;
}

.change-header h3 {
    font-size: 16px;
    font-weight: 600;
    color: var(--white);
}

.change-comparison {
    display: grid;
    grid-template-columns: 1fr 1fr;
}

.change-comparison .before,
.change-comparison .after {
    padding: 20px;
}

.change-comparison .before {
    background: rgba(107, 107, 107, 0.1);
    border-right: 1px solid var(--gray-700);
}

.change-comparison .after {
    background: rgba(255, 107, 0, 0.05);
}

.change-comparison .label {
    display: inline-block;
    font-size: 12px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
    padding: 4px 10px;
    border-radius: var(--radius-sm);
    margin-bottom: 10px;
}

.change-comparison .before .label {
    background: var(--gray-600);
    color: var(--gray-200);
}

.change-comparison .after .label {
    background: var(--orange-primary);
    color: var(--white);
}

.change-comparison p {
    font-size: 14px;
    color: var(--gray-300);
}

/* ===== FAQ Section ===== */
.section-faq {
    background: var(--gray-900);
}

.faq-list {
    max-width: 900px;
    margin: 0 auto;
}

.faq-item {
    background: var(--gray-800);
    border: 1px solid var(--gray-700);
    border-radius: var(--radius-lg);
    margin-bottom: 15px;
    overflow: hidden;
    transition: var(--transition);
}

.faq-item:hover {
    border-color: var(--gray-600);
}

.faq-item.active {
    border-color: var(--orange-primary);
}

.faq-question {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 20px 25px;
    font-size: 16px;
    font-weight: 500;
    color: var(--white);
    text-align: left;
    transition: var(--transition);
}

.faq-question:hover {
    color: var(--orange-primary);
}

.faq-icon {
    font-size: 24px;
    color: var(--orange-primary);
    transition: var(--transition);
}

.faq-item.active .faq-icon {
    transform: rotate(45deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
}

.faq-item.active .faq-answer {
    max-height: 500px;
}

.faq-answer p {
    padding: 0 25px 20px;
    color: var(--gray-300);
    font-size: 15px;
    line-height: 1.7;
}

/* ===== Responsive ===== */
@media (max-width: 1024px) {
    .functions-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .intro-features {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .nav {
        display: none;
    }
    
    .mobile-menu-btn {
        display: flex;
    }
    
    .section-header h1,
    .section-header h2 {
        font-size: 28px;
    }
    
    .section {
        padding: 70px 0;
    }
    
    .section:first-of-type {
        padding-top: 120px;
    }
    
    .functions-grid {
        grid-template-columns: 1fr;
    }
    
    .changes-grid {
        grid-template-columns: 1fr;
    }
    
    .change-comparison {
        grid-template-columns: 1fr;
    }
    
    .change-comparison .before {
        border-right: none;
        border-bottom: 1px solid var(--gray-700);
    }
    
    .intro-features {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .mandatory-alert {
        flex-direction: column;
        text-align: center;
    }
    
    .timeline-item {
        flex-direction: column;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .intro-features {
        grid-template-columns: 1fr;
    }
    
    .feature-card {
        padding: 20px 15px;
    }
    
    .section-header h1,
    .section-header h2 {
        font-size: 24px;
    }
    
    .faq-question {
        font-size: 14px;
        padding: 15px 20px;
    }
    
    .summary-box {
        padding: 20px;
    }
}