/* Base styles */

*,
*::before,
*::after {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    color: #111827;
    background-color: #f9fafb;
    line-height: 1.6;
}

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

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

ul {
    margin: 0;
    padding-left: 1.25rem;
}

p {
    margin: 0 0 1rem;
}

h1, h2, h3, h4 {
    margin: 0 0 0.75rem;
    font-weight: 600;
    color: #030712;
}

/* White headings on dark hero backgrounds */
.hero h1,
.hero h2,
.hero h3,
.page-hero h1,
.page-hero h2,
.page-hero h3 {
    color: #f9fafb;
}

.hero-subtitle,
.hero-meta,
.page-hero p {
    color: #e5e7eb;
}

.container {
    width: 100%;
    max-width: 1120px;
    margin: 0 auto;
    padding: 0 1.25rem;
}

/* Header & navigation */

.site-header {
    position: sticky;
    top: 0;
    z-index: 40;
    background-color: rgba(249, 250, 251, 0.98);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid #e5e7eb;
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem 0;
}

.logo-wrap {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.logo-wrap img {
    width: 40px;
    height: 40px;
}

.logo-text {
    font-size: 0.9rem;
    font-weight: 600;
    letter-spacing: 0.03em;
    text-transform: uppercase;
    color: #047857;
}

.main-nav {
    display: flex;
    align-items: center;
    gap: 1.25rem;
    font-size: 0.9rem;
}

.main-nav a {
    padding: 0.35rem 0.25rem;
    border-radius: 999px;
    transition: color 0.2s ease, background-color 0.2s ease;
}

.main-nav a:hover {
    background-color: #e0f2fe;
    color: #0369a1;
}

.main-nav a.current {
    color: #16a34a;
    font-weight: 600;
}

.nav-toggle {
    display: none;
    border: none;
    background: transparent;
    cursor: pointer;
}

.nav-toggle span {
    display: block;
    width: 22px;
    height: 2px;
    background-color: #111827;
    border-radius: 999px;
    margin: 4px 0;
}

/* Buttons */

.btn-row {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin-top: 1rem;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.65rem 1.4rem;
    border-radius: 999px;
    font-size: 0.9rem;
    font-weight: 500;
    border: 1px solid transparent;
    cursor: pointer;
    transition: background-color 0.2s ease, color 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
}

.btn-primary {
    background-color: #16a34a;
    border-color: #16a34a;
    color: white;
    box-shadow: 0 12px 24px rgba(22, 163, 74, 0.3);
}

.btn-primary:hover {
    background-color: #15803d;
    border-color: #15803d;
}

.btn-secondary {
    background-color: white;
    color: #0369a1;
    border-color: #0369a1;
}

.btn-secondary:hover {
    background-color: #e0f2fe;
}

/* Hero (Home) */

.hero {
    position: relative;
    color: white;
    padding: 6rem 0 5rem;
    overflow: hidden;
}

.hero::before {
    content: "";
    position: absolute;
    inset: 0;
    background-image: url("../images/image-of-nickel-sulphate-for-background.png");
    background-size: cover;
    background-position: center;
    filter: blur(1px);
    transform: scale(1.02);
    z-index: -2;
}

.hero::after {
    content: "";
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at top left, rgba(22, 163, 74, 0.40), transparent 60%),
                linear-gradient(to bottom, rgba(15, 23, 42, 0.60), rgba(15, 23, 42, 0.70));
    z-index: -1;
}

.hero-inner {
    display: grid;
    grid-template-columns: minmax(0, 3fr) minmax(0, 2fr);
    gap: 3rem;
    align-items: center;
}

.hero-kicker {
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.16em;
    color: #bbf7d0;
    margin-bottom: 0.75rem;
}

.hero-title {
    font-size: clamp(2.2rem, 3.1vw, 3rem);
    line-height: 1.1;
    margin-bottom: 1rem;
}

.hero-subtitle {
    font-size: 1rem;
    color: #e5e7eb;
    max-width: 34rem;
}

.hero-quote {
    margin-top: 1.25rem;
    font-style: italic;
    color: #d1fae5;
    border-left: 3px solid #22c55e;
    padding-left: 0.75rem;
}

.hero-meta {
    margin-top: 1.25rem;
    font-size: 0.85rem;
    color: #a5b4fc;
}

/* Generic sections */

.section {
    padding: 4rem 0;
}

.section-alt {
    background-color: #f1f5f9;
}

.section-narrow {
    max-width: 780px;
    margin: 0 auto;
}

.section-header {
    margin-bottom: 2rem;
}

.section-kicker {
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.16em;
    color: #0f766e;
    margin-bottom: 0.25rem;
}

.section-title {
    font-size: 1.7rem;
}

.section-subtitle {
    max-width: 40rem;
    color: #4b5563;
    font-size: 0.95rem;
}

/* Grids & cards */

.grid-2 {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 2.5rem;
}

.grid-3 {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 1.75rem;
}

.card {
    background-color: white;
    border-radius: 1rem;
    padding: 1.5rem;
    box-shadow: 0 12px 28px rgba(15, 23, 42, 0.06);
    border: 1px solid #e5e7eb;
}

.card h3 {
    font-size: 1rem;
}

.card p {
    font-size: 0.9rem;
    color: #4b5563;
}

.about-vision-img {
    max-width: 420px;
    width: 100%;
    border-radius: 1rem;
    display: block;
    margin-top: 0.75rem;
}

/* Page hero (inner pages) */

.page-hero {
    padding: 4.5rem 0 3.5rem;
    background-color: #0f172a;
    color: white;
    position: relative;
    overflow: hidden;
}

.page-hero::after {
    content: "";
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at top left, rgba(59, 130, 246, 0.35), transparent 55%);
    opacity: 0.8;
    pointer-events: none;
}

.page-hero-inner {
    position: relative;
}

.page-hero h1 {
    font-size: 2rem;
    margin-bottom: 0.75rem;
}

.page-hero p {
    max-width: 40rem;
    color: #e5e7eb;
}

/* Partnership hero background */
.partnership-hero {
    background-image: url("../images/IMG_agreement.png");
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    color: #ffffff;
}

.partnership-hero h1,
.partnership-hero p {
    color: #ffffff;
    text-shadow: 0 2px 6px rgba(0,0,0,0.35);
}

/* Specific hero backgrounds */

.about-hero::before,
.technology-hero::before,
.projects-hero::before,
.sustainability-hero::before,
.partnership-hero::before {
    content: "";
    position: absolute;
    inset: 0;
    opacity: 0.25;
    mix-blend-mode: screen;
    background-size: cover;
    background-position: center;
    filter: blur(1px);
}

.about-hero::before {
    background-image: none;
}

.technology-hero::before {
    background-image: none;
}

.projects-hero::before {
    background-image: url("../images/IMG_site-map.png");
    opacity: 0.28;
}

.partnership-hero::before {
    background-image: url("../images/IMG_agreement.png");
}

/* ★ Sustainability hero override – windmill background */

.sustainability-hero::before {
    background-image: url("../images/IMG_windmill.png");
    opacity: 0.55;
    mix-blend-mode: normal;
    filter: none;
    background-size: cover;
    background-position: center;
}

/* Lists */

.list-check {
    list-style: none;
    padding-left: 0;
}

.list-check li {
    position: relative;
    padding-left: 1.4rem;
    margin-bottom: 0.5rem;
    font-size: 0.93rem;
    color: #374151;
}

.list-check li::before {
    content: "•";
    position: absolute;
    left: 0.3rem;
    top: 0;
    color: #16a34a;
    font-weight: 700;
}

/* Tables */

.table-wrap {
    overflow-x: auto;
}

.comparison-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9rem;
}

.comparison-table thead {
    background-color: #e5e7eb;
}

.comparison-table th,
.comparison-table td {
    border: 1px solid #d1d5db;
    padding: 0.65rem 0.75rem;
    text-align: left;
}

.comparison-table th {
    font-weight: 600;
}

.comparison-table tbody tr:nth-child(even) {
    background-color: #f9fafb;
}

/* Definition list (Key metrics) */

.definition-list {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr)); /* 2 колонки на десктопе */
    gap: 1.25rem 3rem;                               /* расстояние между блоками */
    margin: 0;
    padding: 0;
}

.definition-item {
    margin: 0;
}

.definition-item dt {
    font-size: 0.9rem;
    font-weight: 600;
    color: #111827;
}

.definition-item dd {
    margin: 0.25rem 0 0;
    font-size: 0.9rem;
    color: #4b5563;
}

/* Metrics */

.metrics-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 1.5rem;
}

.metric-card {
    background-color: white;
    border-radius: 1rem;
    padding: 1.25rem 1.5rem;
    box-shadow: 0 10px 24px rgba(15, 23, 42, 0.06);
    border: 1px solid #e5e7eb;
}

.metric-value {
    font-size: 1.5rem;
    font-weight: 700;
    color: #0f766e;
    margin-bottom: 0.35rem;
}

.metric-label {
    font-size: 0.85rem;
    color: #4b5563;
}

/* Contact form */

.form-grid {
    display: grid;
    grid-template-columns: minmax(0, 3fr) minmax(0, 2fr);
    gap: 2.5rem;
}

.form-field {
    margin-bottom: 1rem;
}

.form-field label {
    display: block;
    font-size: 0.85rem;
    font-weight: 500;
    margin-bottom: 0.25rem;
}

.form-field input,
.form-field select,
.form-field textarea {
    width: 100%;
    padding: 0.6rem 0.7rem;
    border-radius: 0.75rem;
    border: 1px solid #d1d5db;
    font-size: 0.9rem;
    font-family: inherit;
    background-color: white;
    transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.form-field input:focus,
.form-field select:focus,
.form-field textarea:focus {
    outline: none;
    border-color: #0ea5e9;
    box-shadow: 0 0 0 1px #0ea5e9;
}

.form-field textarea {
    min-height: 140px;
    resize: vertical;
}

.form-error {
    margin-bottom: 0.75rem;
    font-size: 0.85rem;
    color: #b91c1c;
}

.form-actions {
    margin-top: 0.75rem;
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 0.35rem;
}

.form-note {
    font-size: 0.8rem;
    color: #6b7280;
}

/* Footer */

.site-footer {
    margin-top: 3rem;
    padding: 2.5rem 0 2rem;
    background-color: #020617;
    color: #e5e7eb;
}

.footer-inner {
    display: grid;
    grid-template-columns: 3fr 2fr 2fr;
    gap: 2rem;
    font-size: 0.85rem;
}

.footer-title {
    font-size: 0.9rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
}

.footer-links {
    list-style: none;
    padding-left: 0;
    margin: 0;
}

.footer-links li {
    margin-bottom: 0.3rem;
}

.footer-links a {
    color: #e5e7eb;
}

.footer-links a:hover {
    color: #22c55e;
}

.footer-bottom {
    margin-top: 1.5rem;
    border-top: 1px solid #1e293b;
    padding-top: 1rem;
    font-size: 0.8rem;
    color: #9ca3af;
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    gap: 0.75rem;
}

/* Responsive */

@media (max-width: 1024px) {
    .hero-inner {
        grid-template-columns: minmax(0, 1fr);
    }

    .hero-aside {
        max-width: 420px;
        margin-top: 1.5rem;
    }

    .grid-2 {
        grid-template-columns: minmax(0, 1fr);
    }

    .metrics-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .definition-list {
        grid-template-columns: minmax(0, 1fr);
    }

    .team-grid {
        grid-template-columns: repeat(3, minmax(0, 1fr));
    }

    .form-grid {
        grid-template-columns: minmax(0, 1fr);
    }

    .grid-3 {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (max-width: 768px) {
    .header-inner {
        padding: 0.6rem 0;
    }

    .main-nav {
        position: absolute;
        top: 100%;
        right: 0;
        left: 0;
        background-color: rgba(15, 23, 42, 0.98);
        color: #e5e7eb;
        flex-direction: column;
        align-items: flex-start;
        gap: 0;
        padding: 0.5rem 1.25rem 0.75rem;
        max-height: 0;
        overflow: hidden;
        transition: max-height 0.2s ease;
    }

    .main-nav a {
        padding: 0.5rem 0.1rem;
        width: 100%;
    }

    .main-nav.nav-open {
        max-height: 360px;
    }

    .nav-toggle {
        display: block;
    }

    .hero {
        padding: 4.5rem 0 3.5rem;
    }

    .section {
        padding: 3rem 0;
    }

    .metrics-grid {
        grid-template-columns: minmax(0, 1fr);
    }

    .team-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .footer-inner {
        grid-template-columns: minmax(0, 1fr);
    }

    .grid-3 {
        grid-template-columns: minmax(0, 1fr);
    }
}

@media (max-width: 480px) {
    .team-grid {
        grid-template-columns: minmax(0, 1fr);
    }
}