/* ========================================
   CSS Variables & Reset
   ======================================== */
:root {
    --primary-color: #5982D6;
    --secondary-color: #FAFAFA;
    --accent-color: #7534F7;
    --text-white: #FFFFFF;
    --text-dark: #1a1a1a;
    --text-gray: #666666;
    --text-light-gray: #999999;
    --background-dark: #0f0f1e;
    --background-light: #f8f9fa;
    --card-bg: #ffffff;
    --border-color: #e0e0e0;
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.12);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.16);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background-color: var(--text-white);
    overflow-x: hidden;
}

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

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

ul {
    list-style: none;
}

/* ========================================
   Container & Layout
   ======================================== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ========================================
   Navigation Bar
   ======================================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow-sm);
    z-index: 1000;
    transition: var(--transition);
}

.nav-wrapper {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 0;
}

.logo {
    display: flex;
    align-items: center;
    gap: 8px;
    font-family: 'Poppins', sans-serif;
    font-size: 24px;
    font-weight: 700;
    color: var(--primary-color);
}

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

.nav-menu {
    display: flex;
    align-items: center;
    gap: 32px;
}

.nav-link {
    font-weight: 500;
    color: var(--text-dark);
    padding: 8px 12px;
    border-radius: 8px;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 6px;
}

.nav-link:hover {
    color: var(--primary-color);
    background: rgba(89, 130, 214, 0.1);
}

.nav-link.active {
    color: var(--primary-color);
    font-weight: 600;
}

.github-link svg {
    width: 18px;
    height: 18px;
}

.btn-download {
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    color: var(--text-white) !important;
    padding: 10px 20px !important;
    border-radius: 8px;
    font-weight: 600;
}

.btn-download:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
}

.nav-toggle span {
    display: block;
    width: 24px;
    height: 3px;
    background: var(--text-dark);
    border-radius: 3px;
    transition: var(--transition);
}

/* ========================================
   Hero Section
   ======================================== */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 120px 0 80px;
    overflow: hidden;
}

.hero-background {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, #f5f7fa 0%, #e9ecf5 50%, #f0f3f9 100%);
    z-index: -1;
}

.hero-background::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 800px;
    height: 800px;
    background: radial-gradient(circle, rgba(89, 130, 214, 0.15) 0%, transparent 70%);
    border-radius: 50%;
}

.hero-background::after {
    content: '';
    position: absolute;
    bottom: -30%;
    left: -10%;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(117, 52, 247, 0.1) 0%, transparent 70%);
    border-radius: 50%;
}

.hero-content {
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
}

.hero-title {
    font-family: 'Poppins', sans-serif;
    font-size: 56px;
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 24px;
    color: var(--text-dark);
}

.gradient-text {
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-description {
    font-size: 20px;
    color: var(--text-gray);
    margin-bottom: 40px;
    line-height: 1.8;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
}

/* ========================================
   Buttons
   ======================================== */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 32px;
    border-radius: 10px;
    font-weight: 600;
    font-size: 16px;
    cursor: pointer;
    transition: var(--transition);
    border: 2px solid transparent;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    color: var(--text-white);
    box-shadow: var(--shadow-md);
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background: var(--text-white);
    color: var(--primary-color);
    border-color: var(--primary-color);
}

.btn-secondary:hover {
    background: var(--primary-color);
    color: var(--text-white);
}

.btn-outline {
    background: transparent;
    color: var(--primary-color);
    border-color: var(--primary-color);
}

.btn-outline:hover {
    background: var(--primary-color);
    color: var(--text-white);
}

.btn-large {
    padding: 16px 40px;
    font-size: 18px;
}

.btn-extra-large {
    padding: 20px 48px;
    font-size: 20px;
}

.btn svg {
    width: 20px;
    height: 20px;
}

/* ========================================
   Features Section
   ======================================== */
.features {
    padding: 100px 0;
    background: var(--text-white);
}

.section-title {
    font-family: 'Poppins', sans-serif;
    font-size: 42px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 16px;
    color: var(--text-dark);
}

.section-subtitle {
    text-align: center;
    font-size: 18px;
    color: var(--text-gray);
    max-width: 700px;
    margin: 0 auto 60px;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 32px;
    margin-top: 48px;
}

.feature-card {
    background: var(--card-bg);
    padding: 32px;
    border-radius: 16px;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    border: 1px solid var(--border-color);
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
}

.feature-icon {
    font-size: 48px;
    margin-bottom: 20px;
}

.feature-card h3 {
    font-family: 'Poppins', sans-serif;
    font-size: 22px;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text-dark);
}

.feature-card p {
    color: var(--text-gray);
    line-height: 1.7;
}

.inline-link {
    color: var(--primary-color);
    font-weight: 500;
    position: relative;
}

.inline-link:hover {
    color: var(--accent-color);
}

.inline-link::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent-color);
    transition: var(--transition);
}

.inline-link:hover::after {
    width: 100%;
}

/* ========================================
   About Preview Section
   ======================================== */
.about-preview {
    padding: 100px 0;
    background: var(--background-light);
}

.about-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 64px;
    align-items: center;
}

.about-text h2 {
    font-family: 'Poppins', sans-serif;
    font-size: 38px;
    font-weight: 700;
    margin-bottom: 24px;
    color: var(--text-dark);
}

.about-text p {
    color: var(--text-gray);
    margin-bottom: 20px;
    line-height: 1.8;
    font-size: 17px;
}

.about-image {
    display: flex;
    align-items: center;
    justify-content: center;
}

.image-placeholder {
    width: 100%;
    height: 400px;
    background: linear-gradient(135deg, rgba(89, 130, 214, 0.1), rgba(117, 52, 247, 0.1));
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.image-placeholder svg {
    opacity: 0.3;
    stroke: var(--primary-color);
}

/* ========================================
   CTA Section
   ======================================== */
.cta {
    padding: 80px 0;
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    color: var(--text-white);
}

.cta-content {
    text-align: center;
    max-width: 700px;
    margin: 0 auto;
}

.cta h2 {
    font-family: 'Poppins', sans-serif;
    font-size: 42px;
    font-weight: 700;
    margin-bottom: 20px;
}

.cta p {
    font-size: 18px;
    margin-bottom: 32px;
    opacity: 0.95;
}

.cta-buttons {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
}

.cta .btn-primary {
    background: var(--text-white);
    color: var(--primary-color);
}

.cta .btn-outline {
    border-color: var(--text-white);
    color: var(--text-white);
}

.cta .btn-outline:hover {
    background: var(--text-white);
    color: var(--primary-color);
}

/* ========================================
   Footer
   ======================================== */
.footer {
    background: var(--background-dark);
    color: var(--secondary-color);
    padding: 60px 0 24px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 48px;
    margin-bottom: 40px;
}

.footer-section h3,
.footer-section h4 {
    font-family: 'Poppins', sans-serif;
    margin-bottom: 20px;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 24px;
    color: var(--text-white);
}

.footer-section p {
    color: var(--text-light-gray);
    line-height: 1.7;
}

.footer-section ul li {
    margin-bottom: 12px;
}

.footer-section ul li a {
    color: var(--text-light-gray);
}

.footer-section ul li a:hover {
    color: var(--primary-color);
}

.social-links {
    display: flex;
    gap: 16px;
}

.social-links a {
    width: 40px;
    height: 40px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-white);
    transition: var(--transition);
}

.social-links a:hover {
    background: var(--primary-color);
    transform: translateY(-3px);
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 24px;
    text-align: center;
    color: var(--text-light-gray);
}

.footer-credit {
    margin-top: 8px;
    font-size: 14px;
}

/* ========================================
   Page Header
   ======================================== */
.page-header {
    padding: 140px 0 60px;
    text-align: center;
    background: linear-gradient(135deg, #f5f7fa 0%, #e9ecf5 100%);
}

.page-title {
    font-family: 'Poppins', sans-serif;
    font-size: 48px;
    font-weight: 700;
    margin-bottom: 16px;
}

.page-description {
    font-size: 20px;
    color: var(--text-gray);
    max-width: 700px;
    margin: 0 auto;
}

/* ========================================
   About Page
   ======================================== */
.about-section {
    padding: 80px 0;
}

.content-block {
    margin-bottom: 60px;
}

.content-block h2 {
    font-family: 'Poppins', sans-serif;
    font-size: 36px;
    font-weight: 700;
    margin-bottom: 24px;
    color: var(--text-dark);
}

.content-block p {
    color: var(--text-gray);
    font-size: 17px;
    line-height: 1.8;
    margin-bottom: 16px;
}

.highlight-block {
    background: var(--background-light);
    padding: 48px;
    border-radius: 16px;
    margin: 60px 0;
}

.mission-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 32px;
    margin-top: 32px;
}

.mission-item {
    text-align: center;
}

.mission-icon {
    font-size: 56px;
    margin-bottom: 16px;
}

.mission-item h3 {
    font-family: 'Poppins', sans-serif;
    font-size: 22px;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text-dark);
}

.mission-item p {
    color: var(--text-gray);
    font-size: 15px;
}

.values-section {
    margin: 60px 0;
}

.values-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
    margin-top: 32px;
}

.value-card {
    background: var(--card-bg);
    padding: 32px;
    border-radius: 12px;
    border: 2px solid var(--border-color);
    transition: var(--transition);
}

.value-card:hover {
    border-color: var(--primary-color);
    transform: translateY(-4px);
}

.value-card h3 {
    font-family: 'Poppins', sans-serif;
    font-size: 20px;
    margin-bottom: 12px;
    color: var(--text-dark);
}

.value-card p {
    color: var(--text-gray);
    font-size: 15px;
}

.cta-block {
    text-align: center;
    background: linear-gradient(135deg, rgba(89, 130, 214, 0.1), rgba(117, 52, 247, 0.1));
    padding: 60px 40px;
    border-radius: 16px;
    margin-top: 60px;
}

.cta-block h2 {
    font-family: 'Poppins', sans-serif;
    font-size: 36px;
    margin-bottom: 16px;
}

.cta-block p {
    font-size: 18px;
    margin-bottom: 32px;
}

/* ========================================
   Contact Page
   ======================================== */
.contact-section {
    padding: 80px 0;
}

.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 64px;
    margin-bottom: 80px;
}

.contact-info h2 {
    font-family: 'Poppins', sans-serif;
    font-size: 36px;
    font-weight: 700;
    margin-bottom: 20px;
}

.contact-intro {
    color: var(--text-gray);
    font-size: 17px;
    line-height: 1.8;
    margin-bottom: 32px;
}

.contact-features {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.contact-feature {
    display: flex;
    gap: 16px;
    align-items: flex-start;
}

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

.contact-feature h3 {
    font-family: 'Poppins', sans-serif;
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 8px;
}

.contact-feature p {
    color: var(--text-gray);
    font-size: 15px;
}

.contact-form-wrapper {
    display: flex;
    align-items: center;
}

.form-card {
    background: var(--background-light);
    padding: 48px;
    border-radius: 16px;
    text-align: center;
    width: 100%;
}

.form-icon {
    margin-bottom: 24px;
}

.form-icon svg {
    stroke: var(--primary-color);
}

.form-card h3 {
    font-family: 'Poppins', sans-serif;
    font-size: 24px;
    margin-bottom: 16px;
}

.form-card p {
    color: var(--text-gray);
    margin-bottom: 32px;
    line-height: 1.7;
}

.btn-form {
    width: 100%;
    justify-content: center;
}

.contact-alternative {
    text-align: center;
}

.contact-alternative h3 {
    font-family: 'Poppins', sans-serif;
    font-size: 32px;
    margin-bottom: 40px;
}

.alternative-methods {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 32px;
}

.method-card {
    background: var(--card-bg);
    padding: 40px;
    border-radius: 16px;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.method-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
}

.method-icon {
    margin-bottom: 20px;
    color: var(--primary-color);
}

.method-card h4 {
    font-family: 'Poppins', sans-serif;
    font-size: 22px;
    margin-bottom: 12px;
}

.method-card p {
    color: var(--text-gray);
    margin-bottom: 20px;
    line-height: 1.7;
}

.method-link {
    color: var(--primary-color);
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    gap: 6px;
}

.method-link:hover {
    color: var(--accent-color);
}

/* ========================================
   Download Page
   ======================================== */
.download-section {
    padding: 80px 0;
}

.download-hero {
    text-align: center;
    max-width: 700px;
    margin: 0 auto 80px;
}

.download-icon {
    margin-bottom: 24px;
}

.download-icon svg {
    stroke: var(--primary-color);
}

.download-hero h2 {
    font-family: 'Poppins', sans-serif;
    font-size: 36px;
    font-weight: 700;
    margin-bottom: 16px;
}

.download-intro {
    color: var(--text-gray);
    font-size: 17px;
    line-height: 1.8;
    margin-bottom: 32px;
}

.download-main-btn {
    margin-bottom: 16px;
}

.download-note {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    color: var(--text-gray);
    font-size: 14px;
    padding: 12px 20px;
    background: var(--background-light);
    border-radius: 8px;
}

.download-features {
    margin-bottom: 80px;
}

.download-features h3 {
    font-family: 'Poppins', sans-serif;
    font-size: 32px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 40px;
}

.feature-list {
    max-width: 900px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.feature-item {
    display: flex;
    gap: 20px;
    padding: 24px;
    background: var(--card-bg);
    border-radius: 12px;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.feature-item:hover {
    box-shadow: var(--shadow-md);
}

.check-icon {
    width: 32px;
    height: 32px;
    background: var(--primary-color);
    color: var(--text-white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    flex-shrink: 0;
}

.feature-item h4 {
    font-family: 'Poppins', sans-serif;
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 8px;
}

.feature-item p {
    color: var(--text-gray);
    line-height: 1.7;
}

.requirements-section {
    margin-bottom: 80px;
}

.requirements-section h3 {
    font-family: 'Poppins', sans-serif;
    font-size: 32px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 40px;
}

.requirements-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 24px;
}

.requirement-card {
    background: var(--background-light);
    padding: 32px;
    border-radius: 12px;
    text-align: center;
}

.req-icon {
    font-size: 48px;
    margin-bottom: 16px;
}

.requirement-card h4 {
    font-family: 'Poppins', sans-serif;
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 12px;
}

.requirement-card p {
    color: var(--text-gray);
    font-size: 15px;
    line-height: 1.7;
}

.safety-notice {
    background: #fff3cd;
    border: 2px solid #ffc107;
    border-radius: 12px;
    padding: 32px;
    display: flex;
    gap: 24px;
    margin-bottom: 80px;
}

.notice-icon {
    font-size: 48px;
    flex-shrink: 0;
}

.notice-content h3 {
    font-family: 'Poppins', sans-serif;
    font-size: 24px;
    margin-bottom: 16px;
    color: var(--text-dark);
}

.notice-content ul {
    list-style: disc;
    margin-left: 20px;
}

.notice-content li {
    margin-bottom: 12px;
    color: var(--text-dark);
    line-height: 1.7;
}

.help-section {
    text-align: center;
    max-width: 700px;
    margin: 0 auto;
}

.help-section h3 {
    font-family: 'Poppins', sans-serif;
    font-size: 32px;
    margin-bottom: 16px;
}

.help-section p {
    color: var(--text-gray);
    font-size: 17px;
    margin-bottom: 32px;
}

.help-buttons {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
}

/* ========================================
   Responsive Design
   ======================================== */
@media (max-width: 768px) {
    .nav-toggle {
        display: flex;
    }

    .nav-menu {
        position: fixed;
        top: 70px;
        left: -100%;
        width: 100%;
        background: var(--text-white);
        flex-direction: column;
        padding: 24px;
        box-shadow: var(--shadow-lg);
        transition: var(--transition);
        gap: 16px;
    }

    .nav-menu.active {
        left: 0;
    }

    .hero-title {
        font-size: 36px;
    }

    .hero-description {
        font-size: 18px;
    }

    .section-title {
        font-size: 32px;
    }

    .feature-grid {
        grid-template-columns: 1fr;
    }

    .about-content {
        grid-template-columns: 1fr;
    }

    .contact-content {
        grid-template-columns: 1fr;
    }

    .page-title {
        font-size: 36px;
    }

    .hero-buttons,
    .cta-buttons,
    .help-buttons {
        flex-direction: column;
    }

    .btn {
        width: 100%;
        justify-content: center;
    }

    .highlight-block {
        padding: 32px 24px;
    }

    .mission-grid {
        grid-template-columns: 1fr;
    }

    .values-grid {
        grid-template-columns: 1fr;
    }

    .alternative-methods {
        grid-template-columns: 1fr;
    }

    .requirements-grid {
        grid-template-columns: 1fr;
    }

    .safety-notice {
        flex-direction: column;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 16px;
    }

    .hero-title {
        font-size: 28px;
    }

    .section-title {
        font-size: 28px;
    }

    .page-title {
        font-size: 28px;
    }

    .feature-card,
    .value-card,
    .form-card {
        padding: 24px;
    }
}