/* ============================================
   GSMSS Landing Page - Apple-Style CSS
   ============================================ */

/* CSS Variables */
:root {
    --primary-color: #0071e3;
    --primary-hover: #0077ed;
    --text-primary: #1d1d1f;
    --text-secondary: #6e6e73;
    --text-light: #86868b;
    --bg-primary: #ffffff;
    --bg-secondary: #f5f5f7;
    --bg-tertiary: #fbfbfd;
    --border-color: #d2d2d7;
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.12);
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
    --spacing-3xl: 6rem;
    --border-radius: 12px;
    --border-radius-sm: 8px;
    --border-radius-lg: 18px;
    --transition: all 0.3s ease;
    --max-width: 1100px;
}

/* Dark Mode Support */
@media (prefers-color-scheme: dark) {
    :root {
        --text-primary: #f5f5f7;
        --text-secondary: #a1a1a6;
        --text-light: #86868b;
        --bg-primary: #000000;
        --bg-secondary: #1d1d1f;
        --bg-tertiary: #1d1d1f;
        --border-color: #424245;
    }
}

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

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.2;
    color: var(--text-primary);
}

h1 {
    font-size: clamp(2.5rem, 5vw, 4rem);
    letter-spacing: -0.02em;
}

h2 {
    font-size: clamp(2rem, 4vw, 3rem);
    letter-spacing: -0.01em;
}

h3 {
    font-size: clamp(1.5rem, 3vw, 2rem);
}

p {
    color: var(--text-secondary);
    font-size: 1.125rem;
    line-height: 1.7;
}

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

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

/* Container */
.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* Announcement Bar */
.announcement-bar {
    background-color: var(--bg-secondary);
    padding: var(--spacing-xs) 0;
    text-align: center;
    font-size: 0.875rem;
    color: var(--text-secondary);
    border-bottom: 1px solid var(--border-color);
}

/* Header / Navbar */
.header {
    background-color: rgba(255, 255, 255, 0.8);
    backdrop-filter: saturate(180%) blur(20px);
    -webkit-backdrop-filter: saturate(180%) blur(20px);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 1000;
    transition: var(--transition);
}

@media (prefers-color-scheme: dark) {
    .header {
        background-color: rgba(0, 0, 0, 0.8);
    }
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-md) var(--spacing-md);
    max-width: var(--max-width);
    margin: 0 auto;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    letter-spacing: -0.01em;
}

.nav-links {
    display: flex;
    gap: var(--spacing-lg);
    align-items: center;
    list-style: none;
}

.nav-links a {
    color: var(--text-primary);
    font-size: 0.9375rem;
    font-weight: 400;
    padding: var(--spacing-xs) 0;
    position: relative;
}

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

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 1px;
    background-color: var(--text-secondary);
    transition: width 0.3s ease;
}

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

.nav-buttons {
    display: flex;
    gap: var(--spacing-sm);
    align-items: center;
}

.btn {
    display: inline-block;
    padding: 0.625rem 1.25rem;
    border-radius: var(--border-radius);
    font-size: 0.9375rem;
    font-weight: 400;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    border: none;
    font-family: inherit;
}

.btn-secondary {
    background-color: transparent;
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background-color: var(--bg-secondary);
    border-color: var(--text-secondary);
}

.btn-primary {
    background-color: var(--primary-color);
    color: #ffffff;
    padding: 0.625rem 1.5rem;
}

.btn-primary:hover {
    background-color: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* Mobile Menu Toggle */
.menu-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-xs);
    color: var(--text-primary);
    font-size: 1.5rem;
}

.menu-toggle:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
    border-radius: 4px;
}

/* Hero Section */
.hero {
    padding: var(--spacing-3xl) var(--spacing-md);
    text-align: center;
    background: linear-gradient(to bottom, var(--bg-primary), var(--bg-tertiary));
}

.hero h1 {
    margin-bottom: var(--spacing-md);
    max-width: 900px;
    margin-left: auto;
    margin-right: auto;
}

.hero .subtitle {
    font-size: clamp(1.125rem, 2vw, 1.5rem);
    color: var(--text-secondary);
    max-width: 700px;
    margin: 0 auto var(--spacing-xl);
    line-height: 1.6;
}

.hero-buttons {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    margin-bottom: var(--spacing-2xl);
    flex-wrap: wrap;
}

.hero-buttons .btn {
    padding: 0.875rem 2rem;
    font-size: 1rem;
}

.trust-bullets {
    display: flex;
    gap: var(--spacing-xl);
    justify-content: center;
    flex-wrap: wrap;
    font-size: 0.9375rem;
    color: var(--text-secondary);
}

.trust-bullets span {
    position: relative;
    padding-left: 1.5rem;
}

.trust-bullets span::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-weight: 600;
}

/* Social Proof Strip */
.social-proof {
    padding: var(--spacing-lg) var(--spacing-md);
    background-color: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    border-bottom: 1px solid var(--border-color);
    text-align: center;
}

.social-proof-text {
    font-size: 0.875rem;
    color: var(--text-light);
    margin-bottom: var(--spacing-sm);
}

.partners {
    display: flex;
    gap: var(--spacing-xl);
    justify-content: center;
    flex-wrap: wrap;
    font-size: 0.9375rem;
    color: var(--text-secondary);
    font-weight: 500;
}

/* Features Grid */
.features {
    padding: var(--spacing-3xl) var(--spacing-md);
}

.section-header {
    text-align: center;
    margin-bottom: var(--spacing-3xl);
}

.section-header h2 {
    margin-bottom: var(--spacing-sm);
}

.section-header p {
    font-size: 1.125rem;
    max-width: 600px;
    margin: 0 auto;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-2xl);
}

.feature-card {
    background-color: var(--bg-secondary);
    padding: var(--spacing-xl);
    border-radius: var(--border-radius);
    transition: var(--transition);
    border: 1px solid transparent;
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: var(--border-color);
}

.feature-card h3 {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.feature-card p {
    font-size: 1rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

.feature-icon {
    font-size: 2rem;
    margin-bottom: var(--spacing-md);
    display: block;
}

/* How It Works */
.how-it-works {
    padding: var(--spacing-3xl) var(--spacing-md);
    background-color: var(--bg-secondary);
}

.steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-xl);
    margin-top: var(--spacing-2xl);
}

.step {
    text-align: center;
    padding: var(--spacing-lg);
}

.step-number {
    display: inline-block;
    width: 60px;
    height: 60px;
    line-height: 60px;
    background-color: var(--primary-color);
    color: #ffffff;
    border-radius: 50%;
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: var(--spacing-md);
}

.step h3 {
    margin-bottom: var(--spacing-sm);
}

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

/* Screenshots */
.screenshots {
    padding: var(--spacing-3xl) var(--spacing-md);
}

.screenshots-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-xl);
    margin-top: var(--spacing-2xl);
}

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

.screenshot-placeholder {
    width: 100%;
    aspect-ratio: 16 / 10;
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-tertiary) 100%);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-lg);
    margin-bottom: var(--spacing-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-light);
    font-size: 0.875rem;
    transition: var(--transition);
}

.screenshot-placeholder:hover {
    transform: scale(1.02);
    box-shadow: var(--shadow-lg);
}

.screenshot-item h4 {
    font-size: 1.125rem;
    color: var(--text-primary);
    margin-bottom: var(--spacing-xs);
}

.screenshot-item p {
    font-size: 0.9375rem;
    color: var(--text-secondary);
}

/* Pricing */
.pricing {
    padding: var(--spacing-3xl) var(--spacing-md);
    background-color: var(--bg-secondary);
}

.pricing-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-xl);
    margin-top: var(--spacing-2xl);
    max-width: 1000px;
    margin-left: auto;
    margin-right: auto;
}

.pricing-card {
    background-color: var(--bg-primary);
    padding: var(--spacing-xl);
    border-radius: var(--border-radius);
    border: 1px solid var(--border-color);
    transition: var(--transition);
    position: relative;
}

.pricing-card.featured {
    border: 2px solid var(--primary-color);
    transform: scale(1.05);
    box-shadow: var(--shadow-lg);
}

.pricing-card.featured::before {
    content: 'Popular';
    position: absolute;
    top: -12px;
    left: 50%;
    transform: translateX(-50%);
    background-color: var(--primary-color);
    color: #ffffff;
    padding: 0.25rem 1rem;
    border-radius: var(--border-radius-sm);
    font-size: 0.75rem;
    font-weight: 600;
}

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

.pricing-card.featured:hover {
    transform: scale(1.05) translateY(-4px);
}

.pricing-card h3 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-sm);
}

.pricing-price {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
}

.pricing-price .currency {
    font-size: 1.25rem;
    vertical-align: top;
}

.pricing-features {
    list-style: none;
    margin: var(--spacing-lg) 0;
    padding: 0;
}

.pricing-features li {
    padding: var(--spacing-xs) 0;
    padding-left: 1.5rem;
    position: relative;
    color: var(--text-secondary);
}

.pricing-features li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-weight: 600;
}

.pricing-card .btn {
    width: 100%;
    margin-top: var(--spacing-md);
}

/* FAQ */
.faq {
    padding: var(--spacing-3xl) var(--spacing-md);
}

.faq-list {
    max-width: 800px;
    margin: var(--spacing-2xl) auto 0;
}

.faq-item {
    border-bottom: 1px solid var(--border-color);
    padding: var(--spacing-md) 0;
}

.faq-question {
    width: 100%;
    background: none;
    border: none;
    text-align: left;
    font-size: 1.125rem;
    font-weight: 500;
    color: var(--text-primary);
    cursor: pointer;
    padding: var(--spacing-sm) 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-family: inherit;
    transition: var(--transition);
}

.faq-question:hover {
    color: var(--primary-color);
}

.faq-question:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 4px;
    border-radius: 4px;
}

.faq-question::after {
    content: '+';
    font-size: 1.5rem;
    color: var(--text-secondary);
    transition: transform 0.3s ease;
    flex-shrink: 0;
    margin-left: var(--spacing-md);
}

.faq-question.active::after {
    transform: rotate(45deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease, padding 0.3s ease;
    padding: 0 var(--spacing-md) 0 0;
}

.faq-answer.active {
    max-height: 500px;
    padding: var(--spacing-sm) var(--spacing-md) var(--spacing-sm) 0;
}

.faq-answer p {
    font-size: 1rem;
    color: var(--text-secondary);
    line-height: 1.7;
}

/* Final CTA */
.final-cta {
    padding: var(--spacing-3xl) var(--spacing-md);
    background: linear-gradient(to bottom, var(--bg-secondary), var(--bg-primary));
    text-align: center;
}

.final-cta h2 {
    margin-bottom: var(--spacing-md);
}

.final-cta p {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-xl);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.final-cta .btn {
    padding: 1rem 2.5rem;
    font-size: 1.125rem;
}

/* Footer */
.footer {
    background-color: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    padding: var(--spacing-2xl) var(--spacing-md);
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--spacing-md);
    max-width: var(--max-width);
    margin: 0 auto;
}

.footer-links {
    display: flex;
    gap: var(--spacing-lg);
    list-style: none;
    flex-wrap: wrap;
}

.footer-links a {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.footer-links a:hover {
    color: var(--text-primary);
}

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

/* Responsive Design */
@media (max-width: 768px) {
    .nav-links {
        position: fixed;
        top: 70px;
        left: 0;
        right: 0;
        background-color: var(--bg-primary);
        border-bottom: 1px solid var(--border-color);
        flex-direction: column;
        padding: var(--spacing-md);
        gap: var(--spacing-md);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: var(--transition);
        box-shadow: var(--shadow-md);
    }

    .nav-links.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }

    .nav-buttons {
        flex-direction: column;
        width: 100%;
        gap: var(--spacing-sm);
    }

    .nav-buttons .btn {
        width: 100%;
    }

    .menu-toggle {
        display: block;
    }

    .hero {
        padding: var(--spacing-2xl) var(--spacing-md);
    }

    .hero-buttons {
        flex-direction: column;
    }

    .hero-buttons .btn {
        width: 100%;
    }

    .trust-bullets {
        flex-direction: column;
        gap: var(--spacing-sm);
        align-items: center;
    }

    .partners {
        flex-direction: column;
        gap: var(--spacing-sm);
    }

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

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

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

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

    .pricing-card.featured {
        transform: scale(1);
    }

    .pricing-card.featured:hover {
        transform: translateY(-4px);
    }

    .footer-content {
        flex-direction: column;
        text-align: center;
    }

    .footer-links {
        justify-content: center;
    }
}

@media (max-width: 480px) {
    :root {
        --spacing-md: 1rem;
        --spacing-lg: 1.5rem;
        --spacing-xl: 2rem;
        --spacing-2xl: 3rem;
        --spacing-3xl: 4rem;
    }

    .container {
        padding: 0 var(--spacing-sm);
    }

    .nav {
        padding: var(--spacing-sm);
    }

    .logo {
        font-size: 1.25rem;
    }
}