/* ===== Variables CSS ===== */
:root {
    --color-bg: #ffffff;
    --color-bg-alt: #f8fafc;
    --color-bg-dark: #0f172a;
    --color-surface: #ffffff;
    --color-border: #e2e8f0;
    --color-text: #0f172a;
    --color-text-muted: #64748b;
    --color-primary: #4f46e5;
    --color-primary-light: #eef2ff;
    --color-primary-hover: #4338ca;
    --color-accent: #06b6d4;
    --color-accent-light: #ecfeff;
    --color-success: #10b981;
    --color-warning: #f59e0b;

    --font-display: 'Space Grotesk', sans-serif;
    --font-body: 'Inter', sans-serif;

    --space-xs: 0.5rem;
    --space-sm: 0.75rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    --space-3xl: 4rem;
    --space-4xl: 6rem;

    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-2xl: 1.5rem;

    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);

    --transition: 0.2s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-body);
    font-size: 1rem;
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-bg);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

ul, ol {
    list-style: none;
}

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

/* ===== Typography ===== */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-display);
    font-weight: 700;
    line-height: 1.1;
    letter-spacing: -0.02em;
    color: var(--color-text);
}

h1 {
    font-size: clamp(3rem, 10vw, 6rem);
    font-weight: 700;
    letter-spacing: -0.03em;
}

h2 {
    font-size: clamp(2rem, 5vw, 3rem);
}

h3 {
    font-size: 1.25rem;
    font-weight: 600;
}

/* ===== Layout ===== */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
}

.section {
    padding: var(--space-4xl) 0;
}

.section-alt {
    background-color: var(--color-bg-alt);
}

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

.section-header h2 {
    margin-bottom: var(--space-md);
}

.section-header p {
    color: var(--color-text-muted);
    font-size: 1.125rem;
    max-width: 600px;
    margin: 0 auto;
}

/* ===== Navigation ===== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--color-border);
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-md) var(--space-lg);
    max-width: 1200px;
    margin: 0 auto;
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-text);
}

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

.logo-icon svg {
    width: 24px;
    height: 24px;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: var(--space-xl);
}

.nav-links a {
    font-size: 0.9375rem;
    font-weight: 500;
    color: var(--color-text-muted);
    transition: color var(--transition);
}

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

.lang-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-xs) var(--space-sm);
    background: var(--color-bg-alt);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    color: var(--color-text);
    font-size: 0.75rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition);
}

.lang-toggle:hover {
    background: var(--color-border);
}

/* ===== Hero ===== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-4xl) var(--space-lg);
    background: linear-gradient(180deg, var(--color-primary-light) 0%, var(--color-bg) 100%);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 150%;
    height: 600px;
    background: radial-gradient(ellipse at center top, rgba(79, 70, 229, 0.15) 0%, transparent 70%);
    pointer-events: none;
}

.hero-content {
    max-width: 1000px;
    text-align: center;
    position: relative;
    z-index: 1;
}

.hero-brand {
    margin-bottom: var(--space-xl);
}

.hero-logo {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 80px;
    height: 80px;
    background: var(--color-primary);
    border-radius: var(--radius-xl);
    color: white;
    margin-bottom: var(--space-lg);
    box-shadow: var(--shadow-xl);
}

.hero-logo svg {
    width: 48px;
    height: 48px;
}

.hero-title {
    font-size: clamp(3.5rem, 12vw, 7rem);
    font-weight: 700;
    letter-spacing: -0.04em;
    line-height: 1;
    margin-bottom: var(--space-md);
    background: linear-gradient(135deg, var(--color-text) 0%, var(--color-primary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero h1 {
    font-size: clamp(1.5rem, 4vw, 2.5rem);
    font-weight: 500;
    color: var(--color-text-muted);
    margin-bottom: var(--space-xl);
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--color-text-muted);
    max-width: 700px;
    margin: 0 auto var(--space-2xl);
    line-height: 1.7;
}

.hero-actions {
    display: flex;
    gap: var(--space-md);
    justify-content: center;
    flex-wrap: wrap;
}

/* ===== Buttons ===== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    padding: var(--space-md) var(--space-xl);
    font-family: var(--font-body);
    font-size: 1rem;
    font-weight: 600;
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: all var(--transition);
}

.btn-primary {
    background: var(--color-primary);
    color: white;
    border: none;
    box-shadow: var(--shadow-md);
}

.btn-primary:hover {
    background: var(--color-primary-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

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

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

/* ===== AI Banner ===== */
.ai-banner {
    background: var(--color-bg-dark);
    color: white;
    padding: var(--space-3xl) 0;
    position: relative;
    overflow: hidden;
}

.ai-banner::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background:
        radial-gradient(ellipse at 20% 50%, rgba(79, 70, 229, 0.3) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 50%, rgba(6, 182, 212, 0.3) 0%, transparent 50%);
    pointer-events: none;
}

.ai-banner .container {
    position: relative;
    z-index: 1;
}

.ai-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-3xl);
    align-items: center;
}

.ai-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-xs) var(--space-md);
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: var(--radius-xl);
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--color-accent);
    margin-bottom: var(--space-lg);
}

.ai-text h2 {
    color: white;
    font-size: clamp(1.75rem, 4vw, 2.5rem);
    margin-bottom: var(--space-md);
}

.ai-text p {
    color: rgba(255, 255, 255, 0.7);
    font-size: 1.125rem;
    line-height: 1.7;
}

.ai-features {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

.ai-feature {
    display: flex;
    align-items: flex-start;
    gap: var(--space-md);
    padding: var(--space-lg);
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-lg);
}

.ai-feature-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 48px;
    background: var(--color-primary);
    border-radius: var(--radius-md);
    flex-shrink: 0;
}

.ai-feature h4 {
    color: white;
    font-size: 1rem;
    margin-bottom: var(--space-xs);
}

.ai-feature p {
    color: rgba(255, 255, 255, 0.6);
    font-size: 0.875rem;
    margin: 0;
}

/* ===== Key Features (Big & Bold) ===== */
.key-features {
    padding: var(--space-4xl) 0;
}

.key-features-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-lg);
}

.key-feature {
    padding: var(--space-2xl);
    background: var(--color-bg-alt);
    border-radius: var(--radius-2xl);
    border: 1px solid var(--color-border);
    transition: all var(--transition);
}

.key-feature:hover {
    border-color: var(--color-primary);
    box-shadow: var(--shadow-lg);
}

.key-feature-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 56px;
    height: 56px;
    background: var(--color-primary);
    border-radius: var(--radius-lg);
    margin-bottom: var(--space-lg);
    color: white;
}

.key-feature h3 {
    font-size: 1.5rem;
    margin-bottom: var(--space-sm);
}

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

/* ===== Modes Section ===== */
.modes-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-xl);
}

.mode-card {
    padding: var(--space-2xl);
    background: var(--color-surface);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-2xl);
    text-align: center;
    transition: all var(--transition);
}

.mode-card:hover {
    border-color: var(--color-primary);
}

.mode-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 72px;
    height: 72px;
    border-radius: 50%;
    margin-bottom: var(--space-lg);
}

.mode-icon.online {
    background: var(--color-accent-light);
    color: var(--color-accent);
}

.mode-icon.offline {
    background: #fef3c7;
    color: var(--color-warning);
}

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

.mode-card > p {
    color: var(--color-text-muted);
    margin-bottom: var(--space-lg);
}

.mode-features {
    text-align: left;
    background: var(--color-bg-alt);
    padding: var(--space-lg);
    border-radius: var(--radius-lg);
}

.mode-features li {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-sm) 0;
    color: var(--color-text);
    font-size: 0.9375rem;
    font-weight: 500;
}

.mode-features li::before {
    content: '';
    width: 8px;
    height: 8px;
    background: var(--color-success);
    border-radius: 50%;
    flex-shrink: 0;
}

/* ===== Use Cases Grid ===== */
.usecases-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--space-md);
}

.usecase-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-lg);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    font-size: 0.9375rem;
    font-weight: 500;
    color: var(--color-text);
    text-align: center;
    transition: all var(--transition);
}

.usecase-item:hover {
    border-color: var(--color-primary);
    background: var(--color-primary-light);
}

.usecase-item svg {
    color: var(--color-primary);
}

/* ===== Contact ===== */
.contact-card {
    max-width: 500px;
    margin: 0 auto;
    padding: var(--space-2xl);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-2xl);
    text-align: center;
    box-shadow: var(--shadow-lg);
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: var(--space-lg);
}

.contact-item {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-md);
    color: var(--color-text-muted);
}

.contact-item svg {
    color: var(--color-primary);
}

.contact-item a {
    color: var(--color-text);
    font-weight: 500;
    transition: color var(--transition);
}

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

/* ===== Footer ===== */
.footer {
    padding: var(--space-2xl) 0;
    background: var(--color-bg-alt);
    border-top: 1px solid var(--color-border);
}

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

.footer-logo {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    font-family: var(--font-display);
    font-size: 1.25rem;
    font-weight: 700;
}

.footer-logo svg {
    color: var(--color-primary);
}

.footer-content p {
    color: var(--color-text-muted);
    font-size: 0.875rem;
}

/* ===== Responsive ===== */
@media (max-width: 968px) {
    .ai-content {
        grid-template-columns: 1fr;
        text-align: center;
    }

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

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

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

@media (max-width: 768px) {
    .nav-links a:not(.lang-toggle) {
        display: none;
    }

    .hero {
        padding-top: 120px;
    }

    .hero-title {
        font-size: clamp(2.5rem, 15vw, 4rem);
    }

    .section {
        padding: var(--space-3xl) 0;
    }

    .footer-content {
        flex-direction: column;
        gap: var(--space-md);
        text-align: center;
    }
}

@media (max-width: 480px) {
    .usecases-grid {
        grid-template-columns: 1fr;
    }

    .hero-actions {
        flex-direction: column;
        width: 100%;
    }

    .btn {
        width: 100%;
    }
}