:root {
    --bg: #fafafa;
    --bg-alt: #f0f0f0;
    --card-bg: #ffffff;
    --text: #1a1a1a;
    --text-secondary: #555;
    --accent: #6366f1;
    --accent-hover: #4f46e5;
    --border: #e5e5e5;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
    --nav-bg: rgba(250, 250, 250, 0.9);
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg: #0a0a0a;
        --bg-alt: #141414;
        --card-bg: #1a1a1a;
        --text: #e5e5e5;
        --text-secondary: #999;
        --accent: #818cf8;
        --accent-hover: #a5b4fc;
        --border: #2a2a2a;
        --shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
        --nav-bg: rgba(10, 10, 10, 0.9);
    }
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    transition: background 0.3s, color 0.3s;
}

/* ── Navigation ── */

nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    background: var(--nav-bg);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
}

nav .nav-inner {
    max-width: 960px;
    margin: 0 auto;
    padding: 0 24px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

nav .logo {
    font-size: 20px;
    font-weight: 700;
    color: var(--text);
    text-decoration: none;
    letter-spacing: -0.5px;
}

nav .logo span {
    color: var(--accent);
}

nav .nav-links {
    display: flex;
    align-items: center;
    gap: 24px;
    list-style: none;
}

nav .nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 15px;
    transition: color 0.2s;
}

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

.lang-toggle {
    background: none;
    border: 1px solid var(--border);
    border-radius: 6px;
    color: var(--text-secondary);
    font-size: 13px;
    padding: 4px 10px;
    cursor: pointer;
    transition: color 0.2s, border-color 0.2s;
}

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

.burger {
    display: none;
    background: none;
    border: none;
    color: var(--text);
    font-size: 24px;
    cursor: pointer;
    padding: 4px;
}

/* ── Mobile menu ── */

@media (max-width: 640px) {
    .burger {
        display: block;
    }

    nav .nav-links {
        display: none;
        position: absolute;
        top: 60px;
        left: 0;
        right: 0;
        background: var(--nav-bg);
        backdrop-filter: blur(12px);
        flex-direction: column;
        padding: 16px 24px;
        gap: 16px;
        border-bottom: 1px solid var(--border);
    }

    nav .nav-links.open {
        display: flex;
    }
}

/* ── Layout ── */

main {
    max-width: 960px;
    margin: 0 auto;
    padding: 100px 24px 60px;
}

section {
    margin-bottom: 80px;
}

/* ── Hero ── */

.hero {
    text-align: center;
    padding: 80px 0;
}

.hero h1 {
    font-size: 48px;
    font-weight: 700;
    letter-spacing: -1px;
    margin-bottom: 16px;
    line-height: 1.1;
}

.hero h1 span {
    color: var(--accent);
}

.hero p {
    font-size: 20px;
    color: var(--text-secondary);
    max-width: 560px;
    margin: 0 auto 32px;
}

.btn {
    display: inline-block;
    padding: 12px 28px;
    background: var(--accent);
    color: #fff;
    text-decoration: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 500;
    transition: background 0.2s;
    border: none;
    cursor: pointer;
}

.btn:hover {
    background: var(--accent-hover);
}

/* ── Cards grid ── */

.cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 20px;
}

.card {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 32px 24px;
    box-shadow: var(--shadow);
}

.card h3 {
    font-size: 18px;
    margin-bottom: 8px;
}

.card p {
    color: var(--text-secondary);
    font-size: 15px;
}

.card .icon {
    font-size: 32px;
    margin-bottom: 16px;
    display: block;
}

/* ── Section titles ── */

.section-title {
    font-size: 32px;
    font-weight: 700;
    letter-spacing: -0.5px;
    margin-bottom: 12px;
}

.section-subtitle {
    color: var(--text-secondary);
    font-size: 17px;
    margin-bottom: 40px;
    max-width: 560px;
}

/* ── About page ── */

.about-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    align-items: start;
}

.about-content p {
    color: var(--text-secondary);
    font-size: 16px;
    margin-bottom: 16px;
}

.stats {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
}

.stat {
    text-align: center;
    padding: 24px;
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 12px;
}

.stat .number {
    font-size: 36px;
    font-weight: 700;
    color: var(--accent);
}

.stat .label {
    font-size: 14px;
    color: var(--text-secondary);
    margin-top: 4px;
}

@media (max-width: 640px) {
    .about-content {
        grid-template-columns: 1fr;
    }
}

/* ── Contact form ── */

.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.contact-info p {
    color: var(--text-secondary);
    font-size: 16px;
}

.contact-info a {
    color: var(--accent);
    text-decoration: none;
}

.contact-info a:hover {
    text-decoration: underline;
}

form {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

form input,
form textarea {
    width: 100%;
    padding: 12px 16px;
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 15px;
    color: var(--text);
    font-family: inherit;
    transition: border-color 0.2s;
}

form input:focus,
form textarea:focus {
    outline: none;
    border-color: var(--accent);
}

form textarea {
    resize: vertical;
    min-height: 120px;
}

@media (max-width: 640px) {
    .contact-grid {
        grid-template-columns: 1fr;
    }

    .hero h1 {
        font-size: 32px;
    }

    .hero p {
        font-size: 17px;
    }
}

/* ── Footer ── */

footer {
    border-top: 1px solid var(--border);
    padding: 24px;
    text-align: center;
    color: var(--text-secondary);
    font-size: 14px;
}