:root {
    --color-primary: #22c55e;
    --color-primary-dark: #16a34a;
    --color-primary-light: #4ade80;
    --color-text: #1f2937;
    --color-text-light: #6b7280;
    --color-bg: #ffffff;
    --color-bg-alt: #f9fafb;
    --color-bg-dark: #111827;
    --color-border: #e5e7eb;
    --color-white: #ffffff;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1);
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --container-max: 1200px;
    --header-height: 70px;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-bg);
}

a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color 0.2s ease;
}

a:hover {
    color: var(--color-primary-dark);
}

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

.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* Header */
.site-header {
    position: sticky;
    top: 0;
    background: var(--color-white);
    border-bottom: 1px solid var(--color-border);
    z-index: 100;
    height: var(--header-height);
    display: flex;
    align-items: center;
}

.header-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
}

.site-logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-weight: 700;
    font-size: 1.5rem;
    color: var(--color-text);
}

.site-logo:hover {
    color: var(--color-text);
}

.site-logo img {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-sm);
}

.main-nav ul {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.main-nav a {
    color: var(--color-text-light);
    font-weight: 500;
    padding: 0.5rem 0;
    position: relative;
}

.main-nav a:hover,
.main-nav a.active {
    color: var(--color-primary);
}

.main-nav a.active::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--color-primary);
    border-radius: 1px;
}

/* Mobile menu */
.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.mobile-menu-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--color-text);
    margin: 5px 0;
    transition: 0.3s;
}

/* Hero Section */
.hero {
    padding: 4rem 0;
    background: linear-gradient(135deg, var(--color-bg-alt) 0%, var(--color-white) 100%);
    text-align: center;
}

.hero h1 {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.hero p {
    font-size: 1.25rem;
    color: var(--color-text-light);
    max-width: 600px;
    margin: 0 auto 2rem;
}

.hero-cta {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: var(--color-primary);
    color: var(--color-white);
    padding: 0.875rem 2rem;
    border-radius: var(--radius-md);
    font-weight: 600;
    transition: all 0.2s ease;
}

.hero-cta:hover {
    background: var(--color-primary-dark);
    color: var(--color-white);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

/* Category Cards */
.categories {
    padding: 4rem 0;
}

.categories-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
}

.category-card {
    background: var(--color-white);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    transition: all 0.3s ease;
    display: block;
}

.category-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--color-primary);
}

.category-card img {
    width: 64px;
    height: 64px;
    object-fit: contain;
    margin-bottom: 1rem;
}

.category-card h3 {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
    color: var(--color-text);
}

.category-card p {
    color: var(--color-text-light);
    font-size: 0.9375rem;
}

/* Page Header */
.page-header {
    padding: 3rem 0;
    background: var(--color-bg-alt);
    border-bottom: 1px solid var(--color-border);
}

.page-header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.page-header p {
    color: var(--color-text-light);
    font-size: 1.125rem;
}

/* Content Sections */
.content {
    padding: 4rem 0;
}

.content-alt {
    background: var(--color-bg-alt);
}

/* Software Cards */
.software-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 2rem;
}

.software-card {
    background: var(--color-white);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: all 0.3s ease;
}

.software-card:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-4px);
}

.software-card-image {
    width: 100%;
    height: 200px;
    object-fit: cover;
    background: var(--color-bg-alt);
}

.software-card-content {
    padding: 1.5rem;
}

.software-card h3 {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
}

.software-card p {
    color: var(--color-text-light);
    margin-bottom: 1rem;
    font-size: 0.9375rem;
}

.software-card .features {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.software-card .feature-tag {
    background: var(--color-bg-alt);
    color: var(--color-text-light);
    padding: 0.25rem 0.75rem;
    border-radius: 9999px;
    font-size: 0.8125rem;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.625rem 1.25rem;
    border-radius: var(--radius-md);
    font-weight: 500;
    font-size: 0.9375rem;
    transition: all 0.2s ease;
    cursor: pointer;
    border: none;
}

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

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

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

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

/* Feature List */
.feature-list {
    list-style: none;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin: 1.5rem 0;
}

.feature-list li {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--color-text);
}

.feature-list li::before {
    content: '';
    width: 20px;
    height: 20px;
    background: var(--color-primary);
    mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='currentColor' stroke-width='2'%3E%3Cpolyline points='20 6 9 17 4 12'%3E%3C/polyline%3E%3C/svg%3E") center/contain no-repeat;
    flex-shrink: 0;
}

/* About Section */
.about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    align-items: center;
}

.about-content h2 {
    font-size: 2rem;
    margin-bottom: 1rem;
}

.about-content p {
    color: var(--color-text-light);
    margin-bottom: 1rem;
}

.about-image {
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
}

/* Footer */
.site-footer {
    background: var(--color-bg-dark);
    color: var(--color-white);
    padding: 3rem 0 1.5rem;
    margin-top: 4rem;
}

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

.footer-section h4 {
    font-size: 1rem;
    margin-bottom: 1rem;
    color: var(--color-white);
}

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

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

.footer-section a {
    color: var(--color-text-light);
    transition: color 0.2s;
}

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

.footer-bottom {
    text-align: center;
    padding-top: 1.5rem;
    border-top: 1px solid #374151;
    color: var(--color-text-light);
    font-size: 0.875rem;
}

/* Responsive */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 2rem;
    }

    .hero p {
        font-size: 1rem;
    }

    .main-nav {
        display: none;
        position: absolute;
        top: var(--header-height);
        left: 0;
        right: 0;
        background: var(--color-white);
        padding: 1rem;
        border-bottom: 1px solid var(--color-border);
        box-shadow: var(--shadow-md);
    }

    .main-nav.open {
        display: block;
    }

    .main-nav ul {
        flex-direction: column;
        gap: 0;
    }

    .main-nav li {
        border-bottom: 1px solid var(--color-border);
    }

    .main-nav a {
        display: block;
        padding: 0.75rem 0;
    }

    .mobile-menu-toggle {
        display: block;
    }

    .page-header h1 {
        font-size: 2rem;
    }

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

    .about-image {
        order: -1;
    }

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

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

/* Utility Classes */
.text-center { text-align: center; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }
.mt-4 { margin-top: 2rem; }
.py-4 { padding-top: 2rem; padding-bottom: 2rem; }

.section-title {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    text-align: center;
}

.section-subtitle {
    color: var(--color-text-light);
    text-align: center;
    margin-bottom: 3rem;
}

/* Tools Page - 3 Column Grid Layout */
.tools-intro {
    max-width: 800px;
    margin: 0 auto 3rem;
    text-align: center;
    color: var(--color-text-light);
    font-size: 1.125rem;
    line-height: 1.7;
}

.tools-3col {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
    margin-bottom: 3rem;
}

.tool-item {
    background: var(--color-white);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    text-align: center;
    transition: all 0.3s ease;
}

.tool-item:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-2px);
}

.tool-icon {
    width: 108px;
    height: 108px;
    object-fit: contain;
    margin: 0 auto 1rem;
    border-radius: var(--radius-md);
}

.tool-name {
    font-size: 1.125rem;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: 0.5rem;
}

.tool-desc {
    color: var(--color-text-light);
    font-size: 0.9375rem;
    margin-bottom: 0.75rem;
    line-height: 1.5;
}

.tool-tutorial-status {
    color: var(--color-text-light);
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    font-style: italic;
}

.tool-buttons {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.tool-buttons .btn {
    width: 100%;
    justify-content: center;
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

.btn-tutorial {
    background: #3b82f6;
    color: var(--color-white);
}

.btn-tutorial:hover {
    background: #2563eb;
    color: var(--color-white);
}

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

.btn-learn:hover {
    background: var(--color-primary-dark);
    color: var(--color-white);
}

@media (max-width: 1024px) {
    .tools-3col {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 640px) {
    .tools-3col {
        grid-template-columns: 1fr;
    }
}