/* Base styles */
:root {
    --primary-color: #e74c3c;
    --primary-dark: #c0392b;
    --secondary-color: #3498db;
    --dark-color: #2c3e50;
    --light-color: #ecf0f1;
    --gray-color: #95a5a6;
    --light-gray: #bdc3c7;
    --white: #ffffff;
    --black: #000000;
    --success-color: #2ecc71;
    --warning-color: #f39c12;
    --danger-color: #e74c3c;
}

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

body {
    font-family: 'Roboto', Arial, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: var(--white);
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 15px;
}

.section {
    padding: 80px 0;
}

.section__title {
    font-size: 36px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 60px;
    color: var(--dark-color);
    position: relative;
}

.section__title::after {
    content: '';
    display: block;
    width: 80px;
    height: 3px;
    background-color: var(--primary-color);
    margin: 15px auto 0;
}

.btn {
    display: inline-block;
    padding: 12px 30px;
    background-color: var(--primary-color);
    color: var(--white);
    border: none;
    border-radius: 4px;
    font-size: 16px;
    font-weight: 500;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
}

.btn:hover {
    background-color: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

/* Header styles */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: var(--white);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    z-index: 1000;
    padding: 15px 0;
}

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

.logo {
    display: flex;
    flex-direction: column;
}

.logo__text {
    font-size: 24px;
    font-weight: 700;
    color: var(--primary-color);
}

.logo__subtext {
    font-size: 12px;
    color: var(--gray-color);
}

.nav {
    display: flex;
}

.nav__link {
    margin: 0 15px;
    color: var(--dark-color);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

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

.header__contacts {
    display: flex;
    align-items: center;
}

.phone {
    margin-right: 20px;
    font-weight: 500;
    color: var(--dark-color);
    text-decoration: none;
    transition: color 0.3s ease;
}

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

.callback-btn {
    padding: 10px 20px;
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    font-size: 24px;
    color: var(--dark-color);
    cursor: pointer;
}

/* Hero section */
.hero {
    background: linear-gradient(rgba(0, 0, 0, 0.7), rgba(0, 0, 0, 0.7)), url('https://via.placeholder.com/1920x1080?text=Газовое+оборудование') no-repeat center center/cover;
    color: var(--white);
    padding: 200px 0 100px;
    text-align: left;
}

.hero__content {
    max-width: 600px;
}

.hero__title {
    font-size: 42px;
    font-weight: 700;
    margin-bottom: 20px;
    line-height: 1.2;
}

.hero__subtitle {
    font-size: 20px;
    margin-bottom: 30px;
}

.hero__list {
    list-style: none;
    margin-bottom: 40px;
}

.hero__list li {
    margin-bottom: 10px;
    font-size: 18px;
}

.hero__list i {
    margin-right: 10px;
    color: var(--primary-color);
}

.hero__btn {
    font-size: 18px;
    padding: 15px 40px;
}

/* Services section */
.services__grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 30px;
}

.service-card {
    background-color: var(--white);
    border-radius: 8px;
    padding: 30px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.service-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.1);
}

.service-card__icon {
    font-size: 50px;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.service-card__title {
    font-size: 22px;
    margin-bottom: 15px;
    color: var(--dark-color);
}

.service-card__desc {
    color: var(--gray-color);
    margin-bottom: 0;
}

/* Advantages section */
.advantages {
    background-color: #f9f9f9;
}

.advantages__grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.advantage-card {
    background-color: var(--white);
    border-radius: 8px;
    padding: 30px;
    text-align: center;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
}

.advantage-card__icon {
    font-size: 50px;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.advantage-card__title {
    font-size: 20px;
    margin-bottom: 15px;
    color: var(--dark-color);
}

.advantage-card__desc {
    color: var(--gray-color);
}

/* CTA section */
.cta {
    background: linear-gradient(rgba(0, 0, 0, 0.8), rgba(0, 0, 0, 0.8)), url('https://via.placeholder.com/1920x600?text=Консультация+специалиста') no-repeat center center/cover;
    color: var(--white);
    text-align: center;
}

.cta__content {
    max-width: 700px;
    margin: 0 auto;
}

.cta__title {
    font-size: 32px;
    margin-bottom: 20px;
}

.cta__subtitle {
    font-size: 18px;
    margin-bottom: 30px;
}

.cta__form {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
    margin-bottom: 15px;
}

.cta__form input {
    padding: 15px;
    border: none;
    border-radius: 4px;
    font-size: 16px;
}

.cta__form button {
    grid-column: span 2;
}

.cta__note {
    font-size: 14px;
    opacity: 0.8;
}

/* Portfolio section */
.portfolio__grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
}

.portfolio-item {
    position: relative;
    border-radius: 8px;
    overflow: hidden;
    height: 250px;
}

.portfolio-item__img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.5s ease;
}

.portfolio-item:hover .portfolio-item__img {
    transform: scale(1.1);
}

.portfolio-item__overlay {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    background: linear-gradient(transparent, rgba(0, 0, 0, 0.8));
    color: var(--white);
    padding: 20px;
    transform: translateY(100%);
    transition: transform 0.3s ease;
}

.portfolio-item:hover .portfolio-item__overlay {
    transform: translateY(0);
}

.portfolio-item__title {
    font-size: 18px;
    margin-bottom: 5px;
}

.portfolio-item__desc {
    font-size: 14px;
    opacity: 0.8;
}

/* Steps section */
.steps__timeline {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 20px;
    position: relative;
}

.steps__timeline::before {
    content: '';
    position: absolute;
    top: 40px;
    left: 0;
    right: 0;
    height: 3px;
    background-color: var(--light-gray);
    z-index: 1;
}

.step {
    position: relative;
    text-align: center;
    z-index: 2;
}

.step__number {
    width: 80px;
    height: 80px;
    background-color: var(--primary-color);
    color: var(--white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 30px;
    font-weight: 700;
    margin: 0 auto 20px;
    position: relative;
}

.step__title {
    font-size: 18px;
    margin-bottom: 10px;
    color: var(--dark-color);
}

.step__desc {
    font-size: 14px;
    color: var(--gray-color);
}

/* Testimonials section */
.testimonials {
    background-color: #f9f9f9;
}

.testimonials__slider {
    max-width: 800px;
    margin: 0 auto;
}

.testimonial {
    background-color: var(--white);
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
    margin: 0 15px;
}

.testimonial__text {
    font-size: 18px;
    font-style: italic;
    margin-bottom: 20px;
    color: var(--dark-color);
}

.testimonial__author {
    display: flex;
    flex-direction: column;
}

.testimonial__name {
    font-weight: 700;
    color: var(--primary-color);
}

.testimonial__location {
    font-size: 14px;
    color: var(--gray-color);
}

/* Contacts section */
.contacts__grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 50px;
}

.contacts__info {
    display: flex;
    flex-direction: column;
}

.contact-item {
    display: flex;
    align-items: center;
    margin-bottom: 20px;
}

.contact-item i {
    font-size: 20px;
    color: var(--primary-color);
    margin-right: 15px;
    width: 30px;
    text-align: center;
}

.contact-item a {
    color: var(--dark-color);
    text-decoration: none;
    transition: color 0.3s ease;
}

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

.contacts__map {
    height: 400px;
    border-radius: 8px;
    overflow: hidden;
}

/* Footer */
.footer {
    background-color: var(--dark-color);
    color: var(--white);
    padding: 60px 0 0;
}

.footer__grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    margin-bottom: 40px;
}

.footer__title {
    font-size: 20px;
    margin-bottom: 20px;
    color: var(--white);
}

.footer__links {
    list-style: none;
}

.footer__links li {
    margin-bottom: 10px;
}

.footer__links a {
    color: var(--light-gray);
    text-decoration: none;
    transition: color 0.3s ease;
}

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

.footer__text {
    color: var(--light-gray);
    margin-bottom: 20px;
}

.social-links {
    display: flex;
    gap: 15px;
    margin-bottom: 20px;
}

.social-links a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background-color: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    color: var(--white);
    font-size: 18px;
    transition: all 0.3s ease;
}

.social-links a:hover {
    background-color: var(--primary-color);
    transform: translateY(-3px);
}

.footer__btn {
    width: 100%;
}

.footer__bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.footer__copy {
    color: var(--light-gray);
    font-size: 14px;
}

.footer__link {
    color: var(--light-gray);
    font-size: 14px;
    text-decoration: none;
    transition: color 0.3s ease;
}

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

/* Modal */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 2000;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
}

.modal.active {
    opacity: 1;
    visibility: visible;
}

.modal__content {
    background-color: var(--white);
    padding: 40px;
    border-radius: 8px;
    max-width: 500px;
    width: 100%;
    position: relative;
    transform: translateY(-50px);
    transition: transform 0.3s ease;
}

.modal.active .modal__content {
    transform: translateY(0);
}

.modal__close {
    position: absolute;
    top: 15px;
    right: 15px;
    font-size: 24px;
    background: none;
    border: none;
    cursor: pointer;
    color: var(--gray-color);
    transition: color 0.3s ease;
}

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

.modal__title {
    font-size: 24px;
    margin-bottom: 10px;
    color: var(--dark-color);
    text-align: center;
}

.modal__subtitle {
    font-size: 16px;
    color: var(--gray-color);
    text-align: center;
    margin-bottom: 30px;
}

.modal__form {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.modal__form input {
    padding: 15px;
    border: 1px solid var(--light-gray);
    border-radius: 4px;
    font-size: 16px;
}

.modal__note {
    font-size: 12px;
    color: var(--gray-color);
    text-align: center;
    margin-top: 15px;
}

/* Responsive styles */
@media (max-width: 992px) {
    .section {
        padding: 60px 0;
    }

    .section__title {
        font-size: 32px;
        margin-bottom: 40px;
    }

    .hero {
        padding: 180px 0 80px;
    }

    .hero__title {
        font-size: 36px;
    }

    .contacts__grid {
        grid-template-columns: 1fr;
        gap: 30px;
    }

    .contacts__map {
        height: 300px;
    }
}

@media (max-width: 768px) {
    .nav {
        display: none;
    }

    .mobile-menu-btn {
        display: block;
    }

    .header__contacts {
        display: none;
    }

    .hero {
        padding: 150px 0 60px;
        text-align: center;
    }

    .hero__content {
        max-width: 100%;
    }

    .hero__title {
        font-size: 32px;
    }

    .hero__subtitle {
        font-size: 18px;
    }

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

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

    .cta__form button {
        grid-column: span 1;
    }

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

    .steps__timeline::before {
        display: none;
    }

    .step {
        text-align: left;
        display: flex;
        align-items: flex-start;
    }

    .step__number {
        margin: 0 15px 0 0;
        width: 50px;
        height: 50px;
        font-size: 20px;
    }

    .step__content {
        flex: 1;
    }
}

@media (max-width: 576px) {
    .section {
        padding: 40px 0;
    }

    .section__title {
        font-size: 28px;
        margin-bottom: 30px;
    }

    .hero__title {
        font-size: 28px;
    }

    .hero__subtitle {
        font-size: 16px;
    }

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

    .footer__bottom {
        flex-direction: column;
        text-align: center;
        gap: 10px;
    }
}