/* =============================================
   Unit Conversion & Physical Models - Index CSS
   Modern, Responsive, Mobile-First Design
   ============================================= */

/* CSS Variables */
:root {
    --primary-color: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #3b82f6;
    --secondary-color: #0f172a;
    --accent-color: #06b6d4;
    --text-color: #334155;
    --text-light: #64748b;
    --text-white: #ffffff;
    --bg-color: #ffffff;
    --bg-light: #f8fafc;
    --bg-dark: #0f172a;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);
    --gradient-primary: linear-gradient(135deg, #2563eb 0%, #06b6d4 100%);
    --gradient-dark: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
    --transition-fast: 0.15s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
    --border-radius-sm: 0.375rem;
    --border-radius-md: 0.5rem;
    --border-radius-lg: 0.75rem;
    --border-radius-xl: 1rem;
    --border-radius-2xl: 1.5rem;
    --max-width: 1280px;
}

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

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

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

ul,
ol {
    list-style: none;
}

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

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

/* Typography */
h1,
h2,
h3,
h4,
h5,
h6 {
    font-weight: 700;
    line-height: 1.2;
    color: var(--secondary-color);
}

h1 {
    font-size: clamp(2rem, 5vw, 3.5rem);
}

h2 {
    font-size: clamp(1.75rem, 4vw, 2.5rem);
}

h3 {
    font-size: clamp(1.25rem, 3vw, 1.75rem);
}

h4 {
    font-size: clamp(1.125rem, 2.5vw, 1.5rem);
}

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

/* Container */
.container {
    width: 100%;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* Header */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    transition: all var(--transition-normal);
}

.header.scrolled {
    box-shadow: var(--shadow-md);
}

.header .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 72px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--secondary-color);
}

.logo-icon {
    width: 40px;
    height: 40px;
    background: var(--gradient-primary);
    border-radius: var(--border-radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.25rem;
}

/* Desktop Navigation */
.nav-desktop {
    display: none;
}

.nav-desktop ul {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.nav-desktop li a {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.625rem 1rem;
    border-radius: var(--border-radius-md);
    font-weight: 500;
    color: var(--text-color);
    transition: all var(--transition-fast);
}

.nav-desktop li a:hover {
    background: var(--bg-light);
    color: var(--primary-color);
}

.nav-desktop li a i {
    font-size: 1rem;
    opacity: 0.7;
}

/* Mobile Menu Button */
.mobile-menu-btn {
    display: flex;
    flex-direction: column;
    gap: 5px;
    padding: 0.5rem;
    z-index: 1001;
}

.mobile-menu-btn span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--secondary-color);
    border-radius: 2px;
    transition: all var(--transition-fast);
}

.mobile-menu-btn.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.mobile-menu-btn.active span:nth-child(2) {
    opacity: 0;
}

.mobile-menu-btn.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

/* Mobile Navigation */
.nav-mobile {
    position: fixed;
    height: 100vh;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--bg-color);
    z-index: 999;
    display: flex;
    flex-direction: column;
    padding: 100px 2rem 2rem;
    transform: translateX(100%);
    transition: transform var(--transition-normal);
}

.nav-mobile.active {
    transform: translateX(0);
}

.nav-mobile ul {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.nav-mobile li a {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem 1.5rem;
    border-radius: var(--border-radius-lg);
    font-size: 1.125rem;
    font-weight: 500;
    color: var(--text-color);
    background: var(--bg-light);
    transition: all var(--transition-fast);
}

.nav-mobile li a:hover,
.nav-mobile li a.active {
    background: var(--gradient-primary);
    color: white;
}

.nav-mobile li a i {
    font-size: 1.25rem;
    width: 24px;
    text-align: center;
}

/* Hero Section */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: 100px 0 30px;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: -1;
}

.hero-bg img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    opacity: 0.15;
}

.hero-bg::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.9) 0%, rgba(248, 250, 252, 0.95) 100%);
}

.hero-content {
    display: grid;
    gap: 3rem;
    align-items: center;
}

.hero-text {
    text-align: center;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: rgba(37, 99, 235, 0.1);
    border-radius: 50px;
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
}

.hero-badge i {
    font-size: 1rem;
}

.hero-title {
    margin-bottom: 1.5rem;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-description {
    font-size: 1.125rem;
    color: var(--text-light);
    max-width: 600px;
    margin: 0 auto 2rem;
}

.hero-buttons {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    justify-content: center;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.875rem 1.75rem;
    font-size: 1rem;
    font-weight: 600;
    border-radius: var(--border-radius-lg);
    transition: all var(--transition-fast);
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: 0 4px 14px 0 rgba(37, 99, 235, 0.4);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px 0 rgba(37, 99, 235, 0.5);
}

.btn-secondary {
    background: white;
    color: var(--text-color);
    border: 2px solid var(--border-color);
}

.btn-secondary:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.btn-outline {
    background: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
    padding: 0.75rem 2rem;
}

.btn-outline:hover {
    background: var(--primary-color);
    color: white;
    transform: translateY(-2px);
    box-shadow: 0 4px 14px 0 rgba(37, 99, 235, 0.3);
}
.about-image img{
    border-radius: 10px;
    box-shadow: 0 5px 10px rgba(0, 0, 0, 0.5);
}
/* Section More Button */
.section-more {
    text-align: center;
    margin-top: 2.5rem;
}

.hero-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
    margin-top: 3rem;
    padding-top: 3rem;
    border-top: 1px solid var(--border-color);
}

.hero-image {
    display: none;
}

.hero-image img {
    width: 100%;
    max-width: 500px;
    height: auto;
    border-radius: var(--border-radius-xl);
    box-shadow: var(--shadow-xl);
    transform: perspective(1000px) rotateY(-5deg) rotateX(2deg);
    transition: transform var(--transition-normal);
}

.hero-image img:hover {
    transform: perspective(1000px) rotateY(0deg) rotateX(0deg);
}

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

.stat-number {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 0.25rem;
}

.stat-label {
    font-size: 0.875rem;
    color: var(--text-light);
}

/* Section Styles */
.section {
    padding: 80px 0;
}

.section-header {
    text-align: center;
    max-width: 700px;
    margin: 0 auto 3rem;
}

.section-label {
    display: inline-block;
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--primary-color);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: 0.75rem;
}

.section-title {
    margin-bottom: 1rem;
}

.section-description {
    font-size: 1.125rem;
    color: var(--text-light);
}

/* About Section */
.about {
    background: var(--bg-light);
}

.about-content {
    display: grid;
    gap: 2rem;
}

.about-text h3 {
    margin-bottom: 1rem;
}

.about-features {
    display: grid;
    gap: 1rem;
    margin-top: 1.5rem;
}

.about-feature {
    display: flex;
    align-items: flex-start;
    gap: 1rem;
}

.about-feature i {
    flex-shrink: 0;
    width: 24px;
    height: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(37, 99, 235, 0.1);
    color: var(--primary-color);
    border-radius: 50%;
    font-size: 0.75rem;
}

.about-feature span {
    color: var(--text-color);
    font-weight: 500;
}

/* Tools Section */
.tools-grid {
    display: grid;
    gap: 1.5rem;
}

.tool-card {
    background: white;
    border-radius: var(--border-radius-xl);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: all var(--transition-normal);
    border: 1px solid var(--border-color);
}

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

.tool-card-image {
    position: relative;
    height: 180px;
    overflow: hidden;
}

.tool-card-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform var(--transition-slow);
}

.tool-card:hover .tool-card-image img {
    transform: scale(1.1);
}

.tool-card-badge {
    position: absolute;
    top: 1rem;
    left: 1rem;
    padding: 0.375rem 0.75rem;
    background: var(--gradient-primary);
    color: white;
    font-size: 0.75rem;
    font-weight: 600;
    border-radius: 50px;
}

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

.tool-card-title {
    font-size: 1.25rem;
    margin-bottom: 0.75rem;
    color: var(--secondary-color);
}

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

.tool-card-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--primary-color);
    font-weight: 600;
    font-size: 0.9375rem;
}

.tool-card-link i {
    transition: transform var(--transition-fast);
}

.tool-card:hover .tool-card-link i {
    transform: translateX(4px);
}

/* How It Works Section */
.how-it-works {
    background: var(--bg-light);
}

.steps-grid {
    display: grid;
    gap: 2rem;
}

.step-card {
    position: relative;
    background: white;
    padding: 2rem;
    border-radius: var(--border-radius-xl);
    box-shadow: var(--shadow-md);
    text-align: center;
}

.step-number {
    position: absolute;
    top: -15px;
    left: 50%;
    transform: translateX(-50%);
    width: 40px;
    height: 40px;
    background: var(--gradient-primary);
    color: white;
    font-size: 1.25rem;
    font-weight: 700;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 14px 0 rgba(37, 99, 235, 0.4);
}

.step-icon {
    width: 64px;
    height: 64px;
    margin: 1rem auto 1.5rem;
    background: rgba(37, 99, 235, 0.1);
    border-radius: var(--border-radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.75rem;
    color: var(--primary-color);
}

.step-card h3 {
    font-size: 1.25rem;
    margin-bottom: 0.75rem;
}

.step-card p {
    font-size: 0.9375rem;
    color: var(--text-light);
    margin-bottom: 0;
}

/* Guides Section */
.guides-grid {
    display: grid;
    gap: 1.5rem;
}

.guide-card {
    display: flex;
    flex-direction: column;
    background: white;
    border-radius: var(--border-radius-xl);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: all var(--transition-normal);
    border: 1px solid var(--border-color);
}

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

.guide-card-image {
    height: 160px;
    overflow: hidden;
}

.guide-card-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform var(--transition-slow);
}

.guide-card:hover .guide-card-image img {
    transform: scale(1.05);
}

.guide-card-content {
    padding: 1.5rem;
    flex-grow: 1;
    display: flex;
    flex-direction: column;
}

.guide-card-tag {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    background: rgba(6, 182, 212, 0.1);
    color: var(--accent-color);
    font-size: 0.75rem;
    font-weight: 600;
    border-radius: 50px;
    margin-bottom: 0.75rem;
    width: fit-content;
}

.guide-card-title {
    font-size: 1.125rem;
    margin-bottom: 0.75rem;
}

.guide-card-excerpt {
    font-size: 0.9375rem;
    color: var(--text-light);
    flex-grow: 1;
}

.guide-card-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--primary-color);
    font-weight: 600;
    font-size: 0.875rem;
    margin-top: 1rem;
}

/* Trust Section */
.trust {
    background: var(--gradient-dark);
    color: white;
}

.trust .section-label {
    color: var(--accent-color);
}

.trust .section-title {
    color: white;
}

.trust .section-description {
    color: rgba(255, 255, 255, 0.7);
}

.trust-grid {
    display: grid;
    gap: 1.5rem;
}

.trust-card {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--border-radius-xl);
    padding: 2rem;
    text-align: center;
    transition: all var(--transition-normal);
}

.trust-card:hover {
    background: rgba(255, 255, 255, 0.1);
    transform: translateY(-4px);
}

.trust-card-icon {
    width: 56px;
    height: 56px;
    margin: 0 auto 1.5rem;
    background: rgba(6, 182, 212, 0.2);
    border-radius: var(--border-radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    color: var(--accent-color);
}

.trust-card h3 {
    font-size: 1.125rem;
    color: white;
    margin-bottom: 0.75rem;
}

.trust-card p {
    font-size: 0.9375rem;
    color: rgba(255, 255, 255, 0.7);
    margin-bottom: 0;
}

/* CTA Section */
.cta {
    padding: 100px 0;
    text-align: center;
}

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

.cta-title {
    margin-bottom: 1rem;
}

.cta-description {
    font-size: 1.125rem;
    margin-bottom: 2rem;
}

.cta-buttons {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    justify-content: center;
}

/* Footer */
.footer {
    background: var(--secondary-color);
    color: white;
    padding: 60px 0 30px;
}

.footer-content {
    display: grid;
    gap: 2rem;
    margin-bottom: 3rem;
}

.footer-brand {
    max-width: 300px;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.25rem;
    font-weight: 700;
    color: white;
    margin-bottom: 1rem;
}

.footer-logo-icon {
    width: 40px;
    height: 40px;
    background: var(--gradient-primary);
    border-radius: var(--border-radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
}

.footer-brand p {
    color: rgba(255, 255, 255, 0.6);
    font-size: 0.9375rem;
    margin-bottom: 1.5rem;
}

.footer-social {
    display: flex;
    gap: 0.75rem;
}

.footer-social a {
    width: 40px;
    height: 40px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: var(--border-radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.125rem;
    transition: all var(--transition-fast);
}

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

.footer-links h4 {
    color: white;
    font-size: 1rem;
    margin-bottom: 1.25rem;
}

.footer-links ul {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.6);
    font-size: 0.9375rem;
    transition: color var(--transition-fast);
}

.footer-links a:hover {
    color: white;
}

.footer-bottom {
    padding-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    display: flex;
    flex-direction: column;
    gap: 1rem;
    align-items: center;
    text-align: center;
}

.footer-bottom p {
    color: rgba(255, 255, 255, 0.5);
    font-size: 0.875rem;
    margin: 0;
}

.footer-bottom-links {
    display: flex;
    gap: 1.5rem;
}

.footer-bottom-links a {
    color: rgba(255, 255, 255, 0.5);
    font-size: 0.875rem;
}

.footer-bottom-links a:hover {
    color: white;
}
#about{
    padding: 0 0 20px;
}
/* Responsive Styles */
@media (min-width: 640px) {

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

    .tools-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .guides-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .trust-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .footer-content {
        grid-template-columns: repeat(2, 1fr);
    }

    .footer-bottom {
        flex-direction: row;
        justify-content: space-between;
    }
}

@media (min-width: 768px) {
    .section {
        padding: 100px 0;
    }

    .about-content {
        grid-template-columns: 1fr 1fr;
        gap: 3rem;
        align-items: center;
    }

    .steps-grid {
        grid-template-columns: repeat(3, 1fr);
    }

    .step-card {
        text-align: left;
    }

    .step-number {
        left: 2rem;
        transform: none;
    }

    .step-icon {
        margin: 1rem 0 1.5rem;
    }
}

@media (min-width: 1024px) {
    .mobile-menu-btn {
        display: none;
    }

    .nav-desktop {
        display: block;
    }

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

    .hero-image {
        display: block;
    }

    .hero-text {
        text-align: left;
    }

    .hero-description {
        margin: 0 0 2rem;
    }

    .hero-buttons {
        justify-content: flex-start;
    }

    .tools-grid {
        grid-template-columns: repeat(3, 1fr);
    }

    .guides-grid {
        grid-template-columns: repeat(4, 1fr);
    }

    .trust-grid {
        grid-template-columns: repeat(4, 1fr);
    }

    .footer-content {
        grid-template-columns: 2fr 1fr 1fr 1fr;
    }
}


/* Animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }

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

@keyframes fadeIn {
    from {
        opacity: 0;
    }

    to {
        opacity: 1;
    }
}

.animate-fade-in-up {
    animation: fadeInUp 0.6s ease forwards;
}

.animate-fade-in {
    animation: fadeIn 0.6s ease forwards;
}

/* Utility Classes */
.text-center {
    text-align: center;
}

.text-gradient {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}


.tools-filter {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    justify-content: center;
    margin-bottom: 2rem;
  
}

.filter-btn {
    padding: 0.625rem 1.25rem;
    background: white;
    border: 2px solid #e2e8f0;
    border-radius: 50px;
    font-size: 0.9375rem;
    font-weight: 500;
    color: #475569;
    cursor: pointer;
    transition: all 0.3s ease;
    white-space: nowrap;
}

.filter-btn:hover {
    border-color: #6366f1;
    color: #6366f1;
}

.filter-btn.active {
    background: #6366f1;
    border-color: #6366f1;
    color: white;
}

.tool-card {
    transition: all 0.3s ease;
}

.tool-card.hidden {
    display: none;
}

/* FAQ Section */
.faq-grid {
    display: grid;
    gap: 1.5rem;
}

@media (min-width: 768px) {
    .faq-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

.faq-item {
    border: 1px solid #e2e8f0;
    border-radius: 12px;
    overflow: hidden;
}

.faq-question {
    padding: 1.5rem;
    background: white;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    transition: background 0.3s;
}

.faq-question:hover {
    background: #f8fafc;
}

.faq-question h3 {
    margin: 0;
    font-size: 1.125rem;
    font-weight: 600;
    color: #1e293b;
}

.faq-question i {
    transition: transform 0.3s;
    color: #64748b;
}

.faq-answer {
    padding: 0 1.5rem;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease, padding 0.3s ease;
    background: white;
}

.faq-answer p {
    margin: 1.5rem 0;
    color: #475569;
    line-height: 1.6;
}

.faq-item.active .faq-question i {
    transform: rotate(180deg);
}

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

/* Testimonials Section */
.testimonials {
    background: linear-gradient(135deg, #f0f9ff 0%, #e0f2fe 100%);
}

.testimonials-grid {
    display: grid;
    gap: 2rem;
}

@media (min-width: 768px) {
    .testimonials-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

.testimonial-card {
    background: white;
    border-radius: 12px;
    padding: 2rem;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    position: relative;
}

.testimonial-content {
    position: relative;
    margin-bottom: 1.5rem;
}

.testimonial-content i {
    position: absolute;
    top: -1rem;
    left: -1rem;
    font-size: 2rem;
    color: #bae6fd;
    opacity: 0.5;
}

.testimonial-content p {
    margin: 0;
    font-size: 1.125rem;
    line-height: 1.6;
    color: #334155;
}

.testimonial-author {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.testimonial-avatar {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 600;
    font-size: 1.125rem;
}

.testimonial-info h4 {
    margin: 0 0 0.25rem 0;
    font-size: 1rem;
    color: #1e293b;
}

.testimonial-info p {
    margin: 0;
    font-size: 0.875rem;
    color: #64748b;
}

/* Formula Reference Section */
.formula-reference {
    background: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
}

.formula-grid {
    display: grid;
    gap: 1.5rem;
}

@media (min-width: 768px) {
    .formula-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .formula-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

.formula-card {
    background: white;
    border-radius: 12px;
    padding: 1.5rem;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
}

.formula-card h3 {
    margin: 0 0 1rem 0;
    font-size: 1.125rem;
    color: #1e293b;
    border-bottom: 2px solid #e2e8f0;
    padding-bottom: 0.5rem;
}

.formula-item {
    margin-bottom: 1rem;
}

.formula-item:last-child {
    margin-bottom: 0;
}

.formula-equation {
    font-family: 'Courier New', monospace;
    font-size: 1.25rem;
    font-weight: 600;
    color: #6366f1;
    margin-bottom: 0.25rem;
}

.formula-description {
    font-size: 0.875rem;
    color: #64748b;
}