* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: "Saira", sans-serif;
}

:root {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --accent: #3b82f6;
    --accent-hover: #2563eb;
    --border: #475569;
    --shadow: rgba(0, 0, 0, 0.3);
}

.light-mode {
    --bg-primary: #f8fafc;
    --bg-secondary: #ffffff;
    --bg-tertiary: #e2e8f0;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --accent: #3b82f6;
    --accent-hover: #2563eb;
    --border: #cbd5e1;
    --shadow: rgba(0, 0, 0, 0.1);
}

body {
    /* font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif; */
    background: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    transition: all 0.3s ease;
    padding: 0;
}

nav {
    background: var(--bg-secondary);
    border-bottom: 2px solid var(--border);
    padding: 15px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 15px;
}

.nav-links {
    display: flex;
    gap: 25px;
    align-items: center;
}

.nav-links a {
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    cursor: pointer;
}

.nav-links a:hover {
    color: var(--accent);
}

.nav-links a.active {
    color: var(--accent);
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--accent), #8b5cf6);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 20px;
}

header {
    text-align: center;
    margin-bottom: 40px;
}

h1 {
    font-size: 2.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--accent), #8b5cf6);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 10px;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

.theme-toggle {
    background: var(--bg-secondary);
    border: 2px solid var(--border);
    border-radius: 50px;
    padding: 8px 16px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    transition: all 0.3s ease;
}

.theme-toggle:hover {
    transform: scale(1.05);
    border-color: var(--accent);
}

.converter-card {
    background: var(--bg-secondary);
    border-radius: 20px;
    padding: 30px;
    box-shadow: 0 10px 30px var(--shadow);
    margin-bottom: 20px;
}

.category-selector {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 30px;
    justify-content: center;
}

.category-btn {
    background: var(--bg-tertiary);
    border: 2px solid var(--border);
    color: var(--text-primary);
    padding: 12px 20px;
    border-radius: 12px;
    cursor: pointer;
    font-size: 0.9rem;
    font-weight: 600;
    transition: all 0.3s ease;
    white-space: nowrap;
    flex: 0 1 auto;
}

.category-btn:hover {
    border-color: var(--accent);
    transform: translateY(-2px);
}

.category-btn.active {
    background: var(--accent);
    color: white;
    border-color: var(--accent);
}

.conversion-area {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    gap: 20px;
    align-items: center;
    margin-bottom: 30px;
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

select {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 2px solid var(--border);
    padding: 12px 16px;
    border-radius: 12px;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
}

select:focus {
    outline: none;
    border-color: var(--accent);
}

input[type="number"] {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 2px solid var(--border);
    padding: 16px;
    border-radius: 12px;
    font-size: 1.2rem;
    transition: all 0.3s ease;
}

input[type="number"]:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.swap-btn {
    background: var(--accent);
    color: white;
    border: none;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    cursor: pointer;
    font-size: 1.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
}

.swap-btn:hover {
    background: var(--accent-hover);
    transform: rotate(180deg);
}

.result {
    background: linear-gradient(135deg, var(--accent), #8b5cf6);
    padding: 20px;
    border-radius: 12px;
    text-align: center;
    color: white;
    font-size: 1.3rem;
    font-weight: 600;
}

.quick-conversions {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 15px;
}

.quick-card {
    background: var(--bg-tertiary);
    padding: 15px;
    border-radius: 12px;
    border: 2px solid var(--border);
    transition: all 0.3s ease;
}

.quick-card:hover {
    border-color: var(--accent);
    transform: translateY(-2px);
}

.quick-label {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 5px;
}

.quick-value {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--accent);
}

.blog-post, .faq-item {
    background: var(--bg-secondary);
    border-radius: 16px;
    padding: 25px;
    margin-bottom: 20px;
    box-shadow: 0 5px 15px var(--shadow);
    transition: all 0.3s ease;
}

.blog-post:hover, .faq-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px var(--shadow);
}

.blog-post h2, .faq-item h3 {
    color: var(--accent);
    margin-bottom: 15px;
    font-size: 1.5rem;
}

.blog-post .meta {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 15px;
}

.blog-post p, .faq-item p {
    line-height: 1.6;
    margin-bottom: 15px;
    color: var(--text-secondary);
}

.blog-post ul, .faq-item ul {
    margin-left: 20px;
    margin-bottom: 15px;
    color: var(--text-secondary);
}

.blog-post li, .faq-item li {
    margin-bottom: 8px;
    line-height: 1.6;
}

footer {
    background: var(--bg-secondary);
    border-top: 2px solid var(--border);
    padding: 30px 20px;
    margin-top: 50px;
    text-align: center;
}

footer p {
    color: var(--text-secondary);
    margin-bottom: 10px;
}

@media (max-width: 768px) {
    nav {
        justify-content: center;
    }

    .nav-links {
        flex-direction: column;
        gap: 10px;
        width: 100%;
        text-align: center;
    }

    h1 {
        font-size: 2rem;
    }

    .conversion-area {
        grid-template-columns: 1fr;
    }

    .swap-btn {
        transform: rotate(90deg);
    }

    .category-selector {
        justify-content: flex-start;
    }

    .blog-post h2, .faq-item h3 {
        font-size: 1.3rem;
    }
}