* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: Arial, sans-serif;
    background: #f8fafc;
    color: #0f172a;
}

a {
    color: inherit;
}

.page {
    width: 100%;
    max-width: 1500px;
    margin: 0 auto;
    padding: 36px 24px 60px;
}

.top {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 24px;
    margin-bottom: 58px;
}

.top-left {
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.logo {
    margin: 0;
    font-size: 32px;
    line-height: 1;
    font-weight: 800;
    letter-spacing: -1px;
}

.logo a {
    text-decoration: none;
    color: #0f172a;
}

.logo span {
    color: #2563eb;
}

.header-contacts {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

.header-contacts a {
    text-decoration: none;
    color: #0f172a;
    background: #ffffff;
    border: 1px solid #e5e7eb;
    padding: 9px 14px;
    border-radius: 10px;
    font-size: 15px;
    font-weight: 500;
    transition: 0.2s;
}

.header-contacts a:hover {
    color: #2563eb;
    border-color: #2563eb;
}

.top-menu {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-wrap: wrap;
    justify-content: flex-end;
}

.langs {
    display: flex;
    background: #ffffff;
    border: 1px solid #e5e7eb;
    border-radius: 9px;
    overflow: hidden;
}

.lang {
    text-decoration: none;
    padding: 9px 13px;
    font-size: 15px;
    color: #334155;
}

.lang.active {
    background: #2563eb;
    color: #ffffff;
}

.back {
    text-decoration: none;
    color: #334155;
    background: #ffffff;
    border: 1px solid #e5e7eb;
    padding: 9px 14px;
    border-radius: 10px;
    transition: 0.2s;
}

.back:hover {
    color: #2563eb;
    border-color: #2563eb;
}

.right {
    display: flex;
    align-items: center;
    gap: 14px;
}

.hero {
    margin-bottom: 28px;
}

.hero h1 {
    margin: 0 0 16px;
    font-size: 42px;
    line-height: 1.1;
    letter-spacing: -1px;
}

.hero p {
    margin: 0 0 30px;
    font-size: 18px;
    color: #64748b;
}

.search-box {
    width: 100%;
    max-width: 430px;
    height: 44px;
    display: flex;
    align-items: center;
    gap: 10px;
    background: #ffffff;
    border: 1px solid #e5e7eb;
    border-radius: 11px;
    padding: 0 14px;
}

.search-box span {
    color: #64748b;
}

.search-box input {
    width: 100%;
    border: none;
    outline: none;
    font-size: 15px;
    background: transparent;
    color: #0f172a;
}

.search-box input::placeholder {
    color: #94a3b8;
}

.line {
    width: 100%;
    height: 1px;
    background: #e5e7eb;
    margin: 28px 0 30px;
}

.main-layout {
    width: 100%;
}

.section {
    margin-bottom: 40px;
}

.section-title {
    margin: 0 0 18px;
    font-size: 26px;
    line-height: 1.2;
}

.groups {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 18px;
}

.group {
    min-height: 172px;
    background: #ffffff;
    border: 1px solid #e5e7eb;
    border-radius: 12px;
    padding: 20px 18px;
}

.group h3 {
    margin: 0 0 14px;
    font-size: 17px;
    color: #2563eb;
}

.group ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.group li {
    margin: 12px 0;
}

.group li a {
    position: relative;
    display: inline-block;
    text-decoration: none;
    color: #334155;
    font-size: 15.5px;
    line-height: 1.35;
    padding-left: 20px;
    transition: 0.2s;
}

.group li a::before {
    content: "→";
    position: absolute;
    left: 0;
    color: #94a3b8;
}

.group li a:hover {
    color: #2563eb;
}

.empty {
    display: none;
    margin: 25px 0;
    color: #64748b;
    font-size: 18px;
}

/* Страницы алгоритмов */

main {
    width: 100%;
}

.box {
    background: #ffffff;
    border: 1px solid #e5e7eb;
    border-radius: 14px;
    padding: 24px;
    margin-bottom: 22px;
}

.box h2 {
    margin: 0 0 16px;
    font-size: 25px;
    color: #0f172a;
}

.box h3 {
    margin: 18px 0 10px;
    font-size: 19px;
    color: #2563eb;
}

.box p {
    font-size: 16px;
    line-height: 1.65;
    color: #334155;
}

.box ul {
    margin: 12px 0;
    padding-left: 22px;
}

.box li {
    margin: 8px 0;
    color: #334155;
    line-height: 1.55;
}

.scheme {
    background: #f1f5f9;
    border-left: 4px solid #2563eb;
    border-radius: 10px;
    padding: 16px 18px;
    margin: 16px 0;
    color: #334155;
    line-height: 1.7;
}

.note {
    background: #eff6ff;
    border: 1px solid #bfdbfe;
    color: #1e3a8a;
    border-radius: 10px;
    padding: 14px 16px;
    margin: 16px 0;
    line-height: 1.6;
}

pre {
    overflow-x: auto;
    background: #f8fafc;
    border: 1px solid #e5e7eb;
    border-radius: 12px;
    padding: 16px;
}

code {
    font-size: 14.5px;
}

table {
    width: 100%;
    border-collapse: collapse;
    margin: 16px 0;
    overflow: hidden;
    border-radius: 12px;
}

th,
td {
    border: 1px solid #e5e7eb;
    padding: 13px 14px;
    text-align: left;
    color: #334155;
}

th {
    background: #f1f5f9;
    color: #0f172a;
}

@media (max-width: 1000px) {
    .groups {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (max-width: 800px) {
    .page {
        padding: 28px 16px 50px;
    }

    .top {
        flex-direction: column;
        gap: 22px;
        margin-bottom: 40px;
    }

    .top-menu {
        width: 100%;
        justify-content: flex-start;
    }

    .right {
        width: 100%;
        flex-wrap: wrap;
    }

    .hero h1 {
        font-size: 36px;
    }

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

    .box {
        padding: 18px;
    }
}

@media (max-width: 500px) {
    .header-contacts a,
    .lang,
    .back {
        font-size: 14px;
        padding: 8px 11px;
    }

    .logo {
        font-size: 29px;
    }

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

    .section-title {
        font-size: 24px;
    }
}

.top-menu {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-wrap: wrap;
    justify-content: flex-end;
}

.top-btn {
    text-decoration: none;
    border: 1px solid #e5e7eb;
    background: #ffffff;
    color: #0f172a;
    padding: 9px 15px;
    border-radius: 10px;
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    transition: 0.2s;
}

.top-btn:hover {
    color: #2563eb;
    border-color: #2563eb;
}

.top-btn.blue {
    background: #2563eb;
    color: #ffffff;
    border-color: #2563eb;
}

.top-btn.blue:hover {
    background: #1d4ed8;
}

.chat-head {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 24px;
    margin-bottom: 24px;
}

.chat-head h1 {
    margin: 0 0 10px;
    font-size: 42px;
    line-height: 1.1;
}

.chat-head p {
    margin: 0;
    color: #64748b;
    font-size: 18px;
}

.online-box {
    display: flex;
    align-items: center;
    gap: 8px;
    background: #ffffff;
    border: 1px solid #e5e7eb;
    padding: 10px 15px;
    border-radius: 999px;
    color: #334155;
    font-size: 15px;
}

.online-dot {
    width: 9px;
    height: 9px;
    background: #22c55e;
    border-radius: 50%;
}

.chat-page {
    width: 100%;
}

.chat-warning {
    display: none;
    background: #fff7ed;
    border: 1px solid #fed7aa;
    color: #9a3412;
    padding: 14px 16px;
    border-radius: 12px;
    margin-bottom: 18px;
    line-height: 1.5;
}

.chat-warning a {
    color: #ea580c;
    font-weight: 700;
}

.messages {
    height: 570px;
    overflow-y: auto;
    background: #ffffff;
    border: 1px solid #e5e7eb;
    border-radius: 16px;
    padding: 18px;
}

.message-item {
    padding: 13px 0;
    border-bottom: 1px solid #f1f5f9;
}

.message-item:last-child {
    border-bottom: none;
}

.message-top {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 7px;
}

.message-name {
    font-size: 16px;
    font-weight: 800;
}

.message-time {
    color: #94a3b8;
    font-size: 13px;
}

.message-text {
    margin: 0;
    color: #334155;
    font-size: 16px;
    line-height: 1.55;
    white-space: pre-wrap;
    word-break: break-word;
}

.chat-form {
    display: grid;
    grid-template-columns: 1fr 150px;
    gap: 12px;
    margin-top: 14px;
}

.chat-form textarea {
    width: 100%;
    min-height: 58px;
    max-height: 160px;
    resize: vertical;
    border: 1px solid #e5e7eb;
    background: #ffffff;
    border-radius: 13px;
    padding: 14px 15px;
    font-size: 15px;
    outline: none;
    color: #0f172a;
}

.chat-form textarea:focus {
    border-color: #2563eb;
}

.chat-form button {
    border: none;
    background: #2563eb;
    color: #ffffff;
    border-radius: 13px;
    font-size: 15px;
    font-weight: 800;
    cursor: pointer;
    transition: 0.2s;
}

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

.chat-form button:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

@media (max-width: 800px) {
    .chat-head {
        flex-direction: column;
    }

    .chat-head h1 {
        font-size: 36px;
    }

    .messages {
        height: 500px;
    }

    .chat-form {
        grid-template-columns: 1fr;
    }

    .chat-form button {
        height: 48px;
    }
}

.members-head {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 24px;
    margin-bottom: 28px;
}

.members-head h1 {
    margin: 0 0 10px;
    font-size: 42px;
    line-height: 1.1;
}

.members-head p {
    margin: 0;
    color: #64748b;
    font-size: 18px;
}

.members-count {
    display: flex;
    align-items: center;
    gap: 7px;
    background: #ffffff;
    border: 1px solid #e5e7eb;
    padding: 10px 15px;
    border-radius: 999px;
    color: #334155;
    font-size: 15px;
}

.members-count b {
    color: #2563eb;
}

.members-page {
    width: 100%;
}

.members-loading,
.members-empty,
.members-error {
    background: #ffffff;
    border: 1px solid #e5e7eb;
    color: #64748b;
    padding: 18px;
    border-radius: 14px;
    font-size: 16px;
}

.members-empty {
    display: none;
}

.members-error {
    color: #dc2626;
    border-color: #fecaca;
    background: #fef2f2;
}

.members-list {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 18px;
}

.member-card {
    display: flex;
    align-items: center;
    gap: 14px;
    background: #ffffff;
    border: 1px solid #e5e7eb;
    border-radius: 14px;
    padding: 18px;
    transition: 0.2s;
}

.member-card:hover {
    transform: translateY(-2px);
    border-color: #cbd5e1;
    box-shadow: 0 12px 30px rgba(15, 23, 42, 0.06);
}

.member-avatar {
    width: 46px;
    height: 46px;
    flex: 0 0 46px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #ffffff;
    font-weight: 800;
    font-size: 18px;
}

.member-info {
    display: flex;
    flex-direction: column;
    gap: 5px;
    min-width: 0;
}

.member-name {
    font-size: 17px;
    font-weight: 800;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.member-date {
    font-size: 13.5px;
    color: #94a3b8;
}

@media (max-width: 1000px) {
    .members-list {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (max-width: 800px) {
    .members-head {
        flex-direction: column;
    }

    .members-head h1 {
        font-size: 36px;
    }

    .members-list {
        grid-template-columns: 1fr;
    }
}

.auth-page {
    min-height: 520px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.auth-card {
    width: 100%;
    max-width: 430px;
    background: #ffffff;
    border: 1px solid #e5e7eb;
    border-radius: 18px;
    padding: 30px;
    box-shadow: 0 18px 45px rgba(15, 23, 42, 0.06);
}

.auth-card h1 {
    margin: 0 0 10px;
    font-size: 36px;
    line-height: 1.1;
}

.auth-card p {
    margin: 0 0 24px;
    color: #64748b;
    line-height: 1.5;
}

.auth-card label {
    display: block;
    margin: 14px 0 8px;
    color: #334155;
    font-weight: 700;
    font-size: 14px;
}

.auth-input {
    width: 100%;
    height: 46px;
    border: 1px solid #e5e7eb;
    background: #f8fafc;
    border-radius: 12px;
    padding: 0 14px;
    font-size: 15px;
    outline: none;
    color: #0f172a;
}

.auth-input:focus {
    border-color: #2563eb;
    background: #ffffff;
}

.password-row {
    display: grid;
    grid-template-columns: 1fr 48px;
    gap: 10px;
}

.password-row .auth-input {
    margin: 0;
}

.password-row button {
    border: 1px solid #e5e7eb;
    background: #ffffff;
    border-radius: 12px;
    cursor: pointer;
    font-size: 17px;
    transition: 0.2s;
}

.password-row button:hover {
    border-color: #2563eb;
}

.auth-main-btn {
    width: 100%;
    height: 48px;
    margin-top: 20px;
    border: none;
    border-radius: 12px;
    background: #2563eb;
    color: #ffffff;
    font-size: 16px;
    font-weight: 800;
    cursor: pointer;
    transition: 0.2s;
}

.auth-main-btn:hover {
    background: #1d4ed8;
}

.auth-main-btn:disabled {
    opacity: 0.65;
    cursor: not-allowed;
}

.auth-status {
    min-height: 22px;
    margin: 16px 0 0 !important;
    font-size: 14px;
}

.auth-status.info {
    color: #2563eb;
}

.auth-status.success {
    color: #16a34a;
}

.auth-status.error {
    color: #dc2626;
}

.auth-bottom {
    display: flex;
    justify-content: center;
    gap: 8px;
    margin-top: 22px;
    font-size: 15px;
    color: #64748b;
}

.auth-bottom a {
    color: #2563eb;
    font-weight: 700;
    text-decoration: none;
}

.auth-bottom a:hover {
    text-decoration: underline;
}

@media (max-width: 600px) {
    .auth-page {
        align-items: flex-start;
    }

    .auth-card {
        padding: 24px 18px;
    }

    .auth-card h1 {
        font-size: 32px;
    }

    .auth-bottom {
        flex-direction: column;
        align-items: center;
    }
}

.auth-card {
    max-width: 460px;
}

.auth-status {
    min-height: 22px;
    margin: 16px 0 0 !important;
    font-size: 14px;
    line-height: 1.45;
}

.auth-status.info {
    color: #2563eb;
}

.auth-status.success {
    color: #16a34a;
}

.auth-status.error {
    color: #dc2626;
}

.logout-btn {
    display: none;
    align-items: center;
    justify-content: center;
    font-family: inherit;
}

.load-more-btn {
    display: none;
    margin: 24px auto 0;
    border: none;
    background: #2563eb;
    color: #ffffff;
    padding: 12px 22px;
    border-radius: 12px;
    font-size: 15px;
    font-weight: 800;
    cursor: pointer;
    transition: 0.2s;
}

.load-more-btn:hover {
    background: #1d4ed8;
}