:root {
    /* Core Palette - Deeper & Richer */
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #a5b4fc;
    --primary-glow: rgba(99, 102, 241, 0.5);
    --primary-glow-intense: rgba(99, 102, 241, 0.7);

    /* Accent Colors */
    --accent-purple: #a855f7;
    --accent-pink: #ec4899;
    --accent-cyan: #22d3ee;
    --success: #10b981;
    --warning: #f59e0b;
    --error: #ef4444;

    /* Backgrounds - Ultra Dark */
    --bg: #050810;
    --bg-secondary: #0a0e1a;
    --surface: #0f1629;
    --surface-elevated: #1a2035;
    --surface-hover: #252d45;

    /* Text */
    --text: #f8fafc;
    --text-muted: #94a3b8;
    --text-dim: #64748b;

    /* Gradients - More Vibrant */
    --gradient: linear-gradient(135deg, #6366f1 0%, #a855f7 40%, #ec4899 100%);
    --gradient-subtle: linear-gradient(135deg, rgba(99, 102, 241, 0.15) 0%, rgba(168, 85, 247, 0.1) 50%, rgba(236, 72, 153, 0.05) 100%);
    --gradient-mesh: radial-gradient(ellipse at 20% 0%, rgba(99, 102, 241, 0.15) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 100%, rgba(168, 85, 247, 0.10) 0%, transparent 50%);

    /* Shadows & Effects */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.2);
    --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.25);
    --shadow-lg: 0 20px 48px rgba(0, 0, 0, 0.4);
    --shadow-glow: 0 0 60px rgba(99, 102, 241, 0.35);
    --shadow-glow-pink: 0 0 40px rgba(236, 72, 153, 0.25);

    /* Glassmorphism */
    --glass-bg: rgba(15, 22, 41, 0.7);
    --glass-border: rgba(255, 255, 255, 0.08);
    --glass-border-hover: rgba(99, 102, 241, 0.4);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.7;
    min-height: 100vh;
    position: relative;
}

body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--gradient-mesh);
    pointer-events: none;
    z-index: 0;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 24px;
    position: relative;
    z-index: 1;
}

/* Navigation */
.nav {
    padding: 16px 0;
    border-bottom: 1px solid var(--glass-border);
    position: sticky;
    top: 0;
    background: rgba(5, 8, 16, 0.8);
    backdrop-filter: blur(24px) saturate(200%);
    -webkit-backdrop-filter: blur(24px) saturate(200%);
    z-index: 100;
    transition: all 0.3s ease;
}

.nav::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, rgba(99, 102, 241, 0.5), transparent);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.nav:hover::after {
    opacity: 1;
}

.nav .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 24px;
    font-weight: 800;
    background: var(--gradient);
    background-size: 200% 200%;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-decoration: none;
    animation: gradientShift 8s ease infinite;
    letter-spacing: -0.02em;
    transition: transform 0.3s ease;
}

.logo:hover {
    transform: scale(1.05);
}

@keyframes gradientShift {

    0%,
    100% {
        background-position: 0% 50%;
    }

    50% {
        background-position: 100% 50%;
    }
}

.lang-switcher {
    display: flex;
    gap: 8px;
}

.lang-switcher a {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 13px;
    font-weight: 600;
    padding: 6px 12px;
    border-radius: 8px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
}

.lang-switcher a::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--gradient);
    opacity: 0;
    transition: opacity 0.3s ease;
    border-radius: 8px;
    z-index: -1;
}

.lang-switcher a:hover {
    color: var(--text);
    transform: translateY(-2px);
}

.lang-switcher a.active {
    color: white;
    background: rgba(99, 102, 241, 0.2);
    box-shadow: 0 0 20px rgba(99, 102, 241, 0.3);
}

.lang-switcher a.active::before {
    opacity: 0.8;
}

/* Hero */
.hero {
    padding: 80px 0 60px;
    text-align: center;
    position: relative;
}

.hero h1 {
    font-size: clamp(36px, 6vw, 56px);
    font-weight: 900;
    margin-bottom: 20px;
    line-height: 1.1;
    letter-spacing: -0.03em;
    background: linear-gradient(135deg, #ffffff 0%, #e0e7ff 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: fadeInUp 0.8s ease;
}

.hero p {
    color: var(--text-muted);
    font-size: 20px;
    line-height: 1.6;
    max-width: 600px;
    margin: 0 auto;
    animation: fadeInUp 0.8s ease 0.1s both;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.trust-badge {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    margin-top: 32px;
    color: var(--text-muted);
    font-size: 15px;
    animation: fadeInUp 0.8s ease 0.2s both;
    padding: 12px 24px;
    background: rgba(255, 255, 255, 0.03);
    border-radius: 100px;
    border: 1px solid rgba(255, 255, 255, 0.08);
    backdrop-filter: blur(10px);
}

.trust-badge span {
    color: #10b981;
    font-weight: 600;
}

/* Calculator Section */
.calculator-section {
    padding: 40px 0 80px;
    animation: fadeInUp 0.8s ease 0.3s both;
}

.calculator-wrapper {
    background: linear-gradient(145deg, var(--surface) 0%, rgba(10, 15, 30, 0.95) 100%);
    border-radius: 28px;
    padding: 8px;
    box-shadow:
        0 50px 100px -30px rgba(0, 0, 0, 0.7),
        0 0 0 1px var(--glass-border),
        var(--shadow-glow);
    backdrop-filter: blur(40px);
    -webkit-backdrop-filter: blur(40px);
    position: relative;
    overflow: hidden;
    transition: transform 0.4s cubic-bezier(0.4, 0, 0.2, 1), box-shadow 0.4s ease;
}

.calculator-wrapper::before {
    content: '';
    position: absolute;
    top: -1px;
    left: -1px;
    right: -1px;
    bottom: -1px;
    background: var(--gradient);
    border-radius: inherit;
    z-index: -1;
    opacity: 0;
    transition: opacity 0.4s ease;
}

.calculator-wrapper:hover {
    transform: translateY(-6px);
    box-shadow:
        0 60px 120px -35px rgba(0, 0, 0, 0.8),
        0 0 0 1px var(--glass-border-hover),
        var(--shadow-glow),
        var(--shadow-glow-pink);
}

.calculator-wrapper:hover::before {
    opacity: 0.15;
}

/* Content Section */
.content-section {
    padding: 80px 0;
}

.content-section h2 {
    font-size: 32px;
    font-weight: 800;
    margin-bottom: 32px;
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.02em;
}

.content-section h3 {
    font-size: 22px;
    font-weight: 700;
    margin: 32px 0 16px;
    color: var(--text);
}

.content-section p {
    color: var(--text-muted);
    margin-bottom: 20px;
    line-height: 1.8;
    font-size: 16px;
}

.content-section ul {
    color: var(--text-muted);
    padding-left: 28px;
    margin-bottom: 20px;
}

.content-section li {
    margin-bottom: 12px;
    line-height: 1.7;
}

/* FAQ Section */
.faq-section {
    padding: 80px 0;
    background: linear-gradient(135deg, rgba(26, 31, 53, 0.5) 0%, rgba(30, 41, 59, 0.3) 100%);
    position: relative;
}

.faq-section::before {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at 50% 50%, rgba(99, 102, 241, 0.05), transparent 70%);
    pointer-events: none;
}

.faq-section h2 {
    text-align: center;
    font-size: 36px;
    font-weight: 800;
    margin-bottom: 48px;
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.02em;
}

.faq-item {
    background: rgba(10, 14, 26, 0.6);
    border-radius: 16px;
    margin-bottom: 16px;
    overflow: hidden;
    border: 1px solid rgba(255, 255, 255, 0.05);
    transition: all 0.3s ease;
    backdrop-filter: blur(10px);
}

.faq-item:hover {
    border-color: rgba(99, 102, 241, 0.3);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.2);
}

.faq-question {
    padding: 24px 28px;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-weight: 600;
    font-size: 16px;
    transition: all 0.3s ease;
}

.faq-question:hover {
    background: rgba(255, 255, 255, 0.05);
    color: var(--primary-light);
}

.faq-icon {
    color: var(--primary);
    font-size: 24px;
    font-weight: 300;
    transition: transform 0.4s cubic-bezier(0.4, 0, 0.2, 1), color 0.3s ease;
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(99, 102, 241, 0.1);
    border-radius: 8px;
}

.faq-item.open .faq-icon {
    transform: rotate(45deg);
    background: rgba(99, 102, 241, 0.2);
    color: var(--primary-light);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s cubic-bezier(0.4, 0, 0.2, 1), opacity 0.3s ease;
    opacity: 0;
}

.faq-item.open .faq-answer {
    max-height: 500px;
    opacity: 1;
}

.faq-answer p {
    padding: 0 28px 24px;
    color: var(--text-muted);
    line-height: 1.8;
    font-size: 15px;
}

/* Embed CTA */
.embed-cta {
    padding: 80px 0;
    text-align: center;
    position: relative;
}

.embed-cta::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, rgba(99, 102, 241, 0.1), transparent 70%);
    pointer-events: none;
}

.embed-cta h2 {
    font-size: 36px;
    font-weight: 800;
    margin-bottom: 20px;
    letter-spacing: -0.02em;
}

.embed-cta p {
    color: var(--text-muted);
    margin-bottom: 32px;
    font-size: 18px;
    line-height: 1.7;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 16px 36px;
    border-radius: 12px;
    font-size: 16px;
    font-weight: 700;
    text-decoration: none;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
    border: none;
    cursor: pointer;
}

.btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.15);
    transform: translate(-50%, -50%);
    transition: width 0.5s ease, height 0.5s ease;
}

.btn:hover::before {
    width: 350px;
    height: 350px;
}

.btn-primary {
    background: var(--gradient);
    background-size: 200% 200%;
    color: white;
    box-shadow:
        0 8px 24px rgba(99, 102, 241, 0.35),
        inset 0 1px 0 rgba(255, 255, 255, 0.2);
    animation: gradientShift 6s ease infinite;
}

.btn-primary:hover {
    transform: translateY(-3px) scale(1.02);
    box-shadow:
        0 16px 40px rgba(99, 102, 241, 0.45),
        0 0 30px rgba(168, 85, 247, 0.3),
        inset 0 1px 0 rgba(255, 255, 255, 0.25);
}

.btn-primary:active {
    transform: translateY(-1px) scale(1);
}

/* Footer */
.footer {
    padding: 60px 0 40px;
    border-top: 1px solid rgba(255, 255, 255, 0.08);
    text-align: center;
    background: linear-gradient(to bottom, transparent, rgba(10, 14, 26, 0.5));
}

.footer-links {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 32px;
    margin-bottom: 24px;
    list-style: none;
}

.footer-links a {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 14px;
    font-weight: 500;
    transition: all 0.3s ease;
    position: relative;
}

.footer-links a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--gradient);
    transition: width 0.3s ease;
}

.footer-links a:hover {
    color: var(--primary-light);
    transform: translateY(-2px);
}

.footer-links a:hover::after {
    width: 100%;
}

.footer p {
    color: var(--text-dim);
    font-size: 14px;
    opacity: 0.8;
}

/* Responsive */
@media (max-width: 640px) {
    .hero {
        padding: 40px 0 30px;
    }

    .hero h1 {
        font-size: 28px;
    }

    .calculator-wrapper {
        padding: 12px;
        border-radius: 16px;
    }
}

/* 2026 Edition Badge */
.edition-badge {
    color: var(--primary-light);
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.2), rgba(168, 85, 247, 0.15));
    padding: 6px 14px;
    border-radius: 8px;
    font-size: 12px;
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 1px;
    border: 1px solid rgba(99, 102, 241, 0.3);
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.15);
    backdrop-filter: blur(10px);
}

/* Related Calculators & Localized Content */
.related-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 20px;
    margin-top: 32px;
}

.related-card {
    background: var(--surface);
    padding: 24px;
    border-radius: 16px;
    text-decoration: none;
    transition: all 0.35s cubic-bezier(0.4, 0, 0.2, 1);
    border: 1px solid var(--glass-border);
    position: relative;
    overflow: hidden;
}

.related-card::before {
    content: '';
    position: absolute;
    inset: 0;
    background: var(--gradient-subtle);
    opacity: 0;
    transition: opacity 0.35s ease;
    pointer-events: none;
}

.related-card:hover {
    transform: translateY(-6px);
    border-color: var(--glass-border-hover);
    box-shadow:
        0 20px 50px -15px rgba(0, 0, 0, 0.5),
        0 0 30px rgba(99, 102, 241, 0.15);
}

.related-card:hover::before {
    opacity: 1;
}

.related-card h3 {
    color: var(--text);
    font-size: 19px;
    font-weight: 700;
    margin-bottom: 12px;
    position: relative;
    z-index: 1;
    transition: color 0.3s ease;
}

.related-card:hover h3 {
    color: var(--primary-light);
}

.related-card p {
    color: var(--text-muted);
    font-size: 15px;
    margin-bottom: 0;
    line-height: 1.6;
    position: relative;
    z-index: 1;
}

.section-tag {
    display: inline-block;
    color: var(--primary-light);
    font-size: 13px;
    font-weight: 700;
    margin-bottom: 12px;
    text-transform: uppercase;
    letter-spacing: 2px;
    padding: 4px 0;
    position: relative;
}

.section-tag::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 40px;
    height: 2px;
    background: var(--gradient);
}