/* =============================================
   Unit Conversion & Physical Models - Page CSS
   For About, Privacy, Terms, Contact pages
   ============================================= */

:root {
    --primary-color: #2563eb;
    --primary-dark: #1d4ed8;
    --secondary-color: #0f172a;
    --accent-color: #06b6d4;
    --text-color: #334155;
    --text-light: #64748b;
    --bg-color: #ffffff;
    --bg-light: #f8fafc;
    --border-color: #e2e8f0;
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --gradient-primary: linear-gradient(135deg, #2563eb 0%, #06b6d4 100%);
    --transition-fast: 0.15s ease;
    --transition-normal: 0.3s ease;
    --border-radius-md: 0.5rem;
    --border-radius-lg: 0.75rem;
    --border-radius-xl: 1rem;
    --max-width: 1280px;
}

*,
*::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, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-light);
}

a {
    text-decoration: none;
    color: inherit;
}

ul,
ol {
    list-style: none;
}

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

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

.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: 10000;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
}

.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;
}

.nav-desktop {
    display: none;
}

.nav-desktop ul {
    display: flex;
    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;
    transition: all var(--transition-fast);
}

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

.mobile-menu-btn {
    display: flex;
    flex-direction: column;
    gap: 5px;
    padding: 0.5rem;
    z-index: 10001;
}

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

.nav-mobile {
    position: fixed;
    height: 100vh;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--bg-color);
    z-index: 9999;
    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;
    background: var(--bg-light);
    transition: all var(--transition-fast);
}

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

/* Page Hero */
.page-hero {
    position: relative;
    padding: 120px 0 50px;
    background: linear-gradient(135deg, rgba(37, 99, 235, 0.03) 0%, rgba(6, 182, 212, 0.03) 100%);
    border-bottom: 1px solid var(--border-color);
    overflow: hidden;
}

/* Hero Decoration */
.page-hero-decoration {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    pointer-events: none;
    overflow: hidden;
}

.decoration-circle {
    position: absolute;
    border-radius: 50%;
    background: var(--gradient-primary);
    opacity: 0.05;
}

.decoration-circle-1 {
    width: 400px;
    height: 400px;
    top: -200px;
    right: -100px;
}

.decoration-circle-2 {
    width: 300px;
    height: 300px;
    bottom: -150px;
    left: -100px;
}

.decoration-dots {
    position: absolute;
    top: 50%;
    right: 10%;
    width: 100px;
    height: 100px;
    background-image: radial-gradient(circle, var(--primary-color) 1.5px, transparent 1.5px);
    background-size: 20px 20px;
    opacity: 0.15;
    transform: translateY(-50%);
}

/* Hero Badge */
.page-hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: var(--gradient-primary);
    color: white;
    font-size: 0.875rem;
    font-weight: 600;
    border-radius: 50px;
    margin-bottom: 1rem;
}

.page-hero-badge i {
    font-size: 0.75rem;
}

.page-hero-content {
    position: relative;
    z-index: 1;
    display: flex;
    flex-direction: column;
    gap: 2rem;
    text-align: center;
}

.page-hero-text h1 {
    font-size: clamp(2rem, 5vw, 3rem);
    margin-bottom: 1rem;
    color: var(--secondary-color);
}

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

.page-hero-image {
    max-width: 400px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
}

.page-hero-image img {
    border-radius: var(--border-radius-xl);
    box-shadow: var(--shadow-md);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.page-hero-image img:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
}

/* Page Content */
.page-content {
    padding: 60px 0;
}

.content-card {
    background: var(--bg-color);
    border-radius: var(--border-radius-xl);
    padding: 2rem;
    box-shadow: var(--shadow-md);
    max-width: 900px;
    margin: 0 auto;
}

.content-card h2 {
    font-size: 1.5rem;
    margin: 2rem 0 1rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--border-color);
    color: var(--secondary-color);
}

.content-card h2:first-child {
    margin-top: 0;
    padding-top: 0;
    border-top: none;
}

.content-card h3 {
    font-size: 1.25rem;
    margin: 1.5rem 0 0.75rem;
}

.content-card p {
    margin-bottom: 1rem;
    color: var(--text-color);
    line-height: 1.8;
}

.content-card ul,
.content-card ol {
    margin: 1rem 0;
    padding-left: 1.5rem;
}

.content-card ul {
    list-style: disc;
}

.content-card ol {
    list-style: decimal;
}

.content-card li {
    margin-bottom: 0.5rem;
    color: var(--text-color);
}

.content-card a {
    color: var(--primary-color);
    text-decoration: underline;
}

.content-card strong {
    color: var(--secondary-color);
}

/* Info Cards */
.info-cards {
    display: grid;
    gap: 1.5rem;
    margin: 2rem 0;
}

.info-card {
    padding: 1.5rem;
    background: var(--bg-light);
    border-radius: var(--border-radius-lg);
    border: 1px solid var(--border-color);
}

.info-card-icon {
    width: 48px;
    height: 48px;
    background: var(--gradient-primary);
    border-radius: var(--border-radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.25rem;
    margin-bottom: 1rem;
}

.info-card h3 {
    font-size: 1.125rem;
    margin-bottom: 0.5rem;
}

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

/* Contact Form */
.contact-form {
    margin-top: 2rem;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-label {
    display: block;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-color);
}

.form-input,
.form-textarea {
    width: 100%;
    padding: 0.875rem 1rem;
    font-size: 1rem;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius-lg);
    background: var(--bg-color);
    color: var(--text-color);
    transition: all var(--transition-fast);
    font-family: inherit;
}

.form-input:focus,
.form-textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-textarea {
    min-height: 150px;
    resize: vertical;
}

.form-submit {
    width: 100%;
    padding: 1rem 2rem;
    font-size: 1.125rem;
    font-weight: 600;
    background: var(--gradient-primary);
    color: white;
    border-radius: var(--border-radius-lg);
    cursor: pointer;
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
}

.form-submit:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px 0 rgba(37, 99, 235, 0.4);
}

/* Disclaimer Box */
.disclaimer-box {
    padding: 1.5rem;
    background: rgba(245, 158, 11, 0.1);
    border: 1px solid rgba(245, 158, 11, 0.3);
    border-radius: var(--border-radius-lg);
    margin: 2rem 0;
}

.disclaimer-box h3 {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: #f59e0b;
    margin-bottom: 0.75rem;
}

.disclaimer-box p {
    margin: 0;
    font-size: 0.9375rem;
}

/* 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;
}

.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;
    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);
    text-decoration: none;
}

.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;
    text-decoration: none;
}

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

@media (min-width: 640px) {
    .info-cards {
        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) {
    .info-cards {
        grid-template-columns: repeat(3, 1fr);
    }

    .page-hero {
        padding: 140px 0 60px;
    }

    .page-hero-content {
        flex-direction: row;
        align-items: center;
        text-align: left;
        gap: 3rem;
    }

    .page-hero-text {
        flex: 1;
    }

    .page-hero-text p {
        margin: 0;
    }

    .page-hero-image {
        flex-shrink: 0;
        max-width: 320px;
        margin: 0;
    }

    .decoration-circle-1 {
        width: 500px;
        height: 500px;
        top: -250px;
        right: -150px;
    }

    .decoration-circle-2 {
        width: 400px;
        height: 400px;
        bottom: -200px;
        left: -150px;
    }
}

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

    .nav-desktop {
        display: block;
    }

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