* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    font-family: Arial, sans-serif;
    color: #1f2937;
    background: #f5f7fb;
}

/* Header */

.header {
    position: sticky;
    top: 0;
    z-index: 10;
    background: #ffffff;
    border-bottom: 1px solid #e5e7eb;
}

.header__inner {
    max-width: 1280px;
    margin: 0 auto;
    padding: 16px 24px;
    display: flex;
    align-items: center;
    gap: 32px;
}

.logo {
    font-size: 20px;
    font-weight: 700;
    color: #111827;
    text-decoration: none;
    white-space: nowrap;
}

.nav {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.nav__link {
    padding: 9px 14px;
    border-radius: 10px;
    color: #374151;
    text-decoration: none;
    font-size: 14px;
}

.nav__link:hover {
    background: #f3f4f6;
}

.nav__link_active {
    background: #2563eb;
    color: #ffffff;
}

/* Main */

.main {
    max-width: 1280px;
    margin: 0 auto;
    padding: 24px;
}

/* Messages */

.messages {
    margin-bottom: 16px;
}

.message {
    padding: 12px 16px;
    border-radius: 10px;
    margin-bottom: 8px;
    font-size: 14px;
}

.message_success {
    background: #dcfce7;
    color: #166534;
}

.message_error {
    background: #fee2e2;
    color: #991b1b;
}

/* Dashboard */

.dashboard {
    background: #ffffff;
    border: 1px solid #e5e7eb;
    border-radius: 16px;
    overflow: hidden;
    min-height: 720px;
}

.dashboard iframe {
    width: 100%;
    height: 720px;
    border: 0;
    display: block;
}

/* About page */

.about-page {
    max-width: 1100px;
    margin: 0 auto;
    padding: 32px 0;
}

.about-page h1 {
    margin: 0 0 18px;
    font-size: 32px;
    color: #111827;
}

.about-page > p {
    margin: 0 0 24px;
    max-width: 900px;
    color: #4b5563;
    font-size: 17px;
    line-height: 1.6;
}

.about-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
    margin-top: 24px;
}

.about-card {
    padding: 22px;
    background: #ffffff;
    border: 1px solid #e5e7eb;
    border-radius: 16px;
}

.about-card h2 {
    margin: 0 0 10px;
    font-size: 20px;
    color: #111827;
}

.about-card p {
    margin: 0;
    color: #4b5563;
    line-height: 1.55;
}

.about-note {
    margin-top: 20px;
    padding: 16px 18px;
    background: #f9fafb;
    border: 1px solid #e5e7eb;
    border-radius: 14px;
    color: #374151;
    line-height: 1.5;
}

/* Support */

.support {
    margin-top: 18px;
}

.support-details {
    max-width: 520px;
    background: #ffffff;
    border: 1px solid #e5e7eb;
    border-radius: 14px;
    overflow: hidden;
}

.support-summary {
    padding: 14px 16px;
    display: flex;
    align-items: center;
    gap: 12px;
    cursor: pointer;
    list-style: none;
}

.support-summary::-webkit-details-marker {
    display: none;
}

.support-icon {
    width: 34px;
    height: 34px;
    border-radius: 50%;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: #2563eb;
    color: #ffffff;
    font-weight: 700;
    flex-shrink: 0;
}

.support-text strong {
    display: block;
    font-size: 15px;
    color: #111827;
}

.support-text small {
    display: block;
    margin-top: 2px;
    color: #6b7280;
    font-size: 13px;
}

.support-form {
    display: grid;
    gap: 12px;
    padding: 0 16px 16px;
}

.support-form label {
    display: grid;
    gap: 6px;
    font-size: 14px;
    color: #374151;
}

.support-form input,
.support-form textarea {
    width: 100%;
    padding: 10px 11px;
    border: 1px solid #d1d5db;
    border-radius: 10px;
    font: inherit;
}

.support-form input:focus,
.support-form textarea:focus {
    outline: none;
    border-color: #2563eb;
}

.support-form textarea {
    min-height: 90px;
    resize: vertical;
}

.support-form button {
    width: fit-content;
    padding: 10px 16px;
    border: 0;
    border-radius: 10px;
    background: #2563eb;
    color: #ffffff;
    font: inherit;
    cursor: pointer;
}

.support-form button:hover {
    background: #1d4ed8;
}

.hidden-field {
    position: absolute;
    left: -9999px;
    visibility: hidden;
}

/* Footer */

.footer {
    max-width: 1280px;
    margin: 0 auto;
    padding: 24px;
    display: flex;
    justify-content: space-between;
    gap: 16px;
    color: #6b7280;
    font-size: 14px;
}

/* Mobile */

@media (max-width: 768px) {
    .header__inner {
        align-items: flex-start;
        flex-direction: column;
        gap: 12px;
        padding: 16px;
    }

    .main {
        padding: 16px;
    }

    .dashboard {
        min-height: 620px;
    }

    .dashboard iframe {
        height: 620px;
    }

    .about-page {
        padding: 24px 0;
    }

    .about-page h1 {
        font-size: 26px;
    }

    .about-page > p {
        font-size: 15px;
    }

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

    .support-details {
        max-width: 100%;
    }

    .footer {
        flex-direction: column;
        padding: 20px 16px;
    }
}