/* COPPERUA LTD — Premium dark theme, art-deco geometry
   E-learning platform, 2025 */

:root {
    --color-bg: #0a0a0f;
    --color-bg-card: #12121a;
    --color-bg-elevated: #1a1a24;
    --color-accent: #d4a853;
    --color-accent-light: #e8c078;
    --color-accent-dark: #b8923f;
    --color-text: #f5f5f7;
    --color-text-muted: #9a9aab;
    --color-border: rgba(212, 168, 83, 0.2);
    --color-border-hover: rgba(212, 168, 83, 0.5);
    --font-sans: "Segoe UI", system-ui, -apple-system, sans-serif;
    --font-size-base: 1rem;
    --line-height: 1.7;
    --max-width: 1280px;
    --header-height: 70px;
    --transition: 0.3s ease;
    --section-gap: 100px;
    --gap: 24px;
    --radius: 6px;
}

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

html { scroll-behavior: smooth; }

body {
    margin: 0;
    font-family: var(--font-sans);
    font-size: var(--font-size-base);
    line-height: var(--line-height);
    color: var(--color-text);
    background: var(--color-bg);
}

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

a { color: var(--color-accent); text-decoration: none; }
a:hover { color: var(--color-accent-light); }

h1, h2, h3 { margin-top: 0; line-height: 1.2; font-weight: 600; }
h1 { font-size: clamp(2.2rem, 5vw, 3.5rem); letter-spacing: 0.04em; }
h2 { font-size: clamp(1.6rem, 3.5vw, 2.4rem); letter-spacing: 0.03em; margin-bottom: 1rem; }
h3 { font-size: 1.15rem; margin-bottom: 0.5rem; }

.container {
    width: 100%;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
}

.title-line {
    display: block;
    width: 60px;
    height: 2px;
    background: linear-gradient(90deg, var(--color-accent), transparent);
    margin: 0.75rem auto 0;
}
.title-line.left { margin-left: 0; }

.text-center { text-align: center; }
.visually-hidden { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); border: 0; }


/* ========== HEADER ========== */
.site-header {
    position: fixed;
    top: 0; left: 0; right: 0;
    z-index: 1000;
    background: rgba(10, 10, 15, 0.92);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-border);
    transition: transform 0.35s ease;
}
.site-header.hidden { transform: translateY(-100%); }

.header-inner {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
    height: var(--header-height);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    font-weight: 700;
    font-size: 1.1rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--color-text);
}
.logo:hover { color: var(--color-accent); text-decoration: none; }

.burger {
    display: none;
    flex-direction: column;
    gap: 5px;
    padding: 8px;
    background: none;
    border: none;
    cursor: pointer;
}
.burger span {
    width: 22px;
    height: 2px;
    background: var(--color-text);
    transition: var(--transition);
}
.burger.is-open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.burger.is-open span:nth-child(2) { opacity: 0; }
.burger.is-open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

.main-nav ul {
    list-style: none;
    margin: 0; padding: 0;
    display: flex;
    gap: 2rem;
}
.main-nav a {
    color: var(--color-text-muted);
    font-size: 0.9rem;
    letter-spacing: 0.04em;
    text-transform: uppercase;
    padding: 0.25rem 0;
    position: relative;
}
.main-nav a::after {
    content: '';
    position: absolute;
    left: 0; bottom: 0;
    width: 0; height: 1px;
    background: var(--color-accent);
    transition: width 0.3s ease;
}
.main-nav a:hover { color: var(--color-text); }
.main-nav a:hover::after { width: 100%; }


/* ========== HERO ========== */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: calc(var(--header-height) + 60px) 24px 80px;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    inset: 0;
    z-index: 0;
}
.hero-bg img {
    width: 100%; height: 100%;
    object-fit: cover;
    opacity: 0.35;
}
.hero-overlay {
    position: absolute;
    inset: 0;
    background: linear-gradient(180deg, var(--color-bg) 0%, rgba(10,10,15,0.7) 40%, var(--color-bg) 100%);
}

.hero-decor {
    position: absolute;
    top: 50%; left: 50%;
    width: 700px; height: 700px;
    transform: translate(-50%, -50%);
    pointer-events: none;
    z-index: 1;
    opacity: 0.08;
}
.hero-decor::before,
.hero-decor::after {
    content: '';
    position: absolute;
    border: 1px solid var(--color-accent);
    border-radius: 50%;
}
.hero-decor::before { inset: 0; }
.hero-decor::after { inset: 80px; }

.hero-content {
    position: relative;
    z-index: 2;
    max-width: 680px;
    margin: 0 auto;
    text-align: center;
}

.hero-content h1 {
    margin-bottom: 1rem;
    text-transform: uppercase;
}
.hero-lead {
    font-size: 1.1rem;
    color: var(--color-text-muted);
    margin-bottom: 2.5rem;
    max-width: 520px;
    margin-left: auto;
    margin-right: auto;
}

.hero-tabs { margin-top: 3rem; }
.hero-tabs-nav {
    display: flex;
    justify-content: center;
    gap: 0.5rem;
    flex-wrap: wrap;
    margin-bottom: 1.5rem;
}
.hero-tabs-nav button {
    background: transparent;
    border: 1px solid var(--color-border);
    color: var(--color-text-muted);
    padding: 0.6rem 1.2rem;
    font-size: 0.85rem;
    letter-spacing: 0.03em;
    cursor: pointer;
    transition: var(--transition);
    border-radius: var(--radius);
}
.hero-tabs-nav button:hover {
    border-color: var(--color-border-hover);
    color: var(--color-text);
}
.hero-tabs-nav button.active {
    background: var(--color-accent);
    border-color: var(--color-accent);
    color: var(--color-bg);
}
.hero-tab-panel {
    display: none;
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 1.5rem 2rem;
    text-align: left;
    max-width: 540px;
    margin: 0 auto;
}
.hero-tab-panel.active { display: block; }
.hero-tab-panel p { margin: 0; color: var(--color-text-muted); font-size: 0.95rem; }

.hero-cta {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-top: 2.5rem;
    flex-wrap: wrap;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 48px;
    padding: 0.75rem 1.75rem;
    font-size: 0.95rem;
    font-weight: 600;
    letter-spacing: 0.04em;
    text-transform: uppercase;
    border-radius: var(--radius);
    border: 1px solid transparent;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
}
.btn-primary {
    background: var(--color-accent);
    color: var(--color-bg);
    border-color: var(--color-accent);
}
.btn-primary:hover {
    background: var(--color-accent-light);
    border-color: var(--color-accent-light);
    text-decoration: none;
}
.btn-outline {
    background: transparent;
    color: var(--color-text);
    border-color: var(--color-border-hover);
}
.btn-outline:hover {
    background: rgba(212, 168, 83, 0.1);
    border-color: var(--color-accent);
    color: var(--color-accent);
    text-decoration: none;
}


/* ========== SECTIONS ========== */
.section { padding: var(--section-gap) 0; }
.section-alt { background: var(--color-bg-card); }
.section-intro {
    max-width: 600px;
    margin: 0 auto 3rem;
    color: var(--color-text-muted);
    font-size: 1.05rem;
}


/* ========== STATS ========== */
.stats-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: var(--gap);
    margin-bottom: 4rem;
}
.stat-item {
    text-align: center;
    padding: 2rem 1rem;
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    background: var(--color-bg-card);
}
.stat-number {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--color-accent);
    line-height: 1;
    margin-bottom: 0.5rem;
}
.stat-label {
    font-size: 0.85rem;
    color: var(--color-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}


/* ========== CARDS ========== */
.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--gap);
}

.card {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    overflow: hidden;
    transition: border-color var(--transition), transform var(--transition);
}
.card:hover {
    border-color: var(--color-border-hover);
    transform: translateY(-4px);
}
.card-img {
    aspect-ratio: 16/10;
    overflow: hidden;
    background: var(--color-bg-elevated);
}
.card-img img {
    width: 100%; height: 100%;
    object-fit: cover;
    transition: transform 0.4s ease;
}
.card:hover .card-img img { transform: scale(1.04); }
.card-body { padding: 1.5rem; }
.card-body h3 { color: var(--color-text); }
.card-body p { margin: 0; color: var(--color-text-muted); font-size: 0.95rem; }


/* ========== FEATURES ========== */
.feature-block {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    align-items: center;
    margin-bottom: 4rem;
}
.feature-block:last-child { margin-bottom: 0; }
.feature-block.reverse { direction: rtl; }
.feature-block.reverse > * { direction: ltr; }

.feature-img {
    border-radius: var(--radius);
    overflow: hidden;
    border: 1px solid var(--color-border);
    aspect-ratio: 4/3;
    background: var(--color-bg-elevated);
}
.feature-img img { width: 100%; height: 100%; object-fit: cover; }
.feature-text h3 { font-size: 1.4rem; margin-bottom: 0.75rem; }
.feature-text p { color: var(--color-text-muted); margin: 0; }

.features-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: var(--gap);
    list-style: none;
    margin: 0; padding: 0;
}
.features-list li {
    padding: 1.25rem 1.5rem;
    background: var(--color-bg-elevated);
    border-left: 3px solid var(--color-accent);
    border-radius: 0 var(--radius) var(--radius) 0;
    font-weight: 500;
    transition: background var(--transition);
}
.features-list li:hover { background: var(--color-bg-card); }


/* ========== SOLUTIONS ========== */
.solutions-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--gap);
}
.solution-card {
    padding: 2rem;
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    position: relative;
    overflow: hidden;
    transition: border-color var(--transition);
}
.solution-card::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--color-accent), var(--color-accent-dark));
}
.solution-card:hover { border-color: var(--color-border-hover); }
.solution-card h3 { margin-top: 0; }
.solution-card p { margin: 0; color: var(--color-text-muted); }


/* ========== HOW IT WORKS / STEPS ========== */
.steps-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--gap);
    counter-reset: step-counter;
}
.step-item {
    padding: 2rem;
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    position: relative;
    transition: border-color var(--transition), transform var(--transition);
}
.step-item:hover {
    border-color: var(--color-border-hover);
    transform: translateY(-3px);
}
.step-number {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--color-accent);
    opacity: 0.3;
    line-height: 1;
    margin-bottom: 1rem;
}
.step-item h3 {
    margin-top: 0;
    color: var(--color-text);
}
.step-item p {
    margin: 0;
    color: var(--color-text-muted);
    font-size: 0.95rem;
}


/* ========== FAQ ========== */
.faq-list {
    max-width: 800px;
    margin: 0 auto;
}
.faq-item {
    border-bottom: 1px solid var(--color-border);
}
.faq-item:first-child {
    border-top: 1px solid var(--color-border);
}
.faq-question {
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.25rem 0;
    background: none;
    border: none;
    color: var(--color-text);
    font-size: 1rem;
    font-weight: 500;
    text-align: left;
    cursor: pointer;
    transition: color var(--transition);
}
.faq-question:hover {
    color: var(--color-accent);
}
.faq-icon {
    width: 20px;
    height: 20px;
    position: relative;
    flex-shrink: 0;
    margin-left: 1rem;
}
.faq-icon::before,
.faq-icon::after {
    content: '';
    position: absolute;
    background: var(--color-accent);
    transition: transform var(--transition);
}
.faq-icon::before {
    width: 100%;
    height: 2px;
    top: 50%;
    left: 0;
    transform: translateY(-50%);
}
.faq-icon::after {
    width: 2px;
    height: 100%;
    left: 50%;
    top: 0;
    transform: translateX(-50%);
}
.faq-item.open .faq-icon::after {
    transform: translateX(-50%) rotate(90deg);
}
.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.35s ease, padding 0.35s ease;
}
.faq-item.open .faq-answer {
    max-height: 300px;
    padding-bottom: 1.25rem;
}
.faq-answer p {
    margin: 0;
    color: var(--color-text-muted);
    font-size: 0.95rem;
    line-height: 1.7;
}


/* ========== ABOUT ========== */
.about-text {
    max-width: 800px;
    margin: 0 auto;
    color: var(--color-text-muted);
    font-size: 1.05rem;
    line-height: 1.8;
}


/* ========== CONTACT ========== */
.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    align-items: start;
}
.contact-info {
    padding: 2rem;
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
}
.contact-info p { margin: 0 0 0.75rem; color: var(--color-text-muted); }
.contact-info a { color: var(--color-accent); }
.contact-info a:hover { color: var(--color-accent-light); }

.contact-form label {
    display: block;
    margin-bottom: 0.4rem;
    margin-top: 1rem;
    font-size: 0.9rem;
    color: var(--color-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.04em;
}
.contact-form label:first-child { margin-top: 0; }
.contact-form input,
.contact-form textarea {
    width: 100%;
    padding: 0.75rem 1rem;
    font-family: inherit;
    font-size: 1rem;
    color: var(--color-text);
    background: var(--color-bg-elevated);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    transition: border-color var(--transition);
}
.contact-form input:focus,
.contact-form textarea:focus {
    outline: none;
    border-color: var(--color-accent);
}
.contact-form textarea { min-height: 120px; resize: vertical; }
.contact-form button { margin-top: 1.5rem; }


/* ========== FOOTER ========== */
.site-footer {
    background: var(--color-bg-card);
    border-top: 1px solid var(--color-border);
    padding: 60px 0 0;
    margin-top: var(--section-gap);
}
.footer-inner {
    display: grid;
    grid-template-columns: 1.2fr 1fr 1fr;
    gap: 2rem;
    padding-bottom: 2rem;
}
.footer-col h4 {
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--color-accent);
    margin-bottom: 1rem;
}
.footer-col p { margin: 0 0 0.5rem; color: var(--color-text-muted); font-size: 0.9rem; }
.footer-col a { color: var(--color-text-muted); }
.footer-col a:hover { color: var(--color-accent); }
.footer-col ul { list-style: none; margin: 0; padding: 0; }
.footer-col li { margin-bottom: 0.4rem; }

.footer-bottom {
    border-top: 1px solid var(--color-border);
    padding: 1.25rem 24px;
    text-align: center;
    font-size: 0.85rem;
    color: var(--color-text-muted);
}


/* ========== COOKIE ========== */
.cookie-banner {
    position: fixed;
    bottom: 0; left: 0; right: 0;
    z-index: 9999;
    background: var(--color-bg-card);
    border-top: 1px solid var(--color-border);
    padding: 1rem 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    flex-wrap: wrap;
}
.cookie-banner.hidden { display: none; }
.cookie-banner p { margin: 0; font-size: 0.9rem; color: var(--color-text-muted); flex: 1 1 300px; }
.cookie-banner a { color: var(--color-accent); }
.cookie-accept {
    min-height: 44px;
    padding: 0.6rem 1.5rem;
    background: var(--color-accent);
    color: var(--color-bg);
    border: none;
    border-radius: var(--radius);
    font-weight: 600;
    cursor: pointer;
    transition: background var(--transition);
}
.cookie-accept:hover { background: var(--color-accent-light); }


/* ========== POLICY PAGES ========== */
.page-content {
    padding: calc(var(--header-height) + 60px) 24px var(--section-gap);
    max-width: 760px;
    margin: 0 auto;
}
.page-content h1 { margin-bottom: 1rem; }
.page-content h2 { font-size: 1.2rem; margin-top: 2.5rem; margin-bottom: 0.75rem; }
.page-content p, .page-content li { color: var(--color-text-muted); margin-bottom: 0.75rem; }
.page-content ul { padding-left: 1.25rem; }
.page-content a { color: var(--color-accent); }

.thanks-box { text-align: center; padding: 4rem 1rem; }
.thanks-box h1 { margin-bottom: 1rem; }
.thanks-box p { margin-bottom: 2rem; color: var(--color-text-muted); }


/* ========== RESPONSIVE ========== */
@media (max-width: 900px) {
    .footer-inner { grid-template-columns: 1fr 1fr; }
    .contact-grid { grid-template-columns: 1fr; }
    .feature-block, .feature-block.reverse { grid-template-columns: 1fr; direction: ltr; }
    .feature-block .feature-img { order: -1; }
}

@media (max-width: 768px) {
    :root { --section-gap: 70px; }
    .burger { display: flex; }
    .main-nav {
        position: fixed;
        top: var(--header-height);
        left: 0; right: 0;
        background: var(--color-bg);
        border-bottom: 1px solid var(--color-border);
        max-height: 0;
        overflow: hidden;
        transition: max-height 0.35s ease;
    }
    .main-nav.is-open { max-height: 400px; }
    .main-nav ul { flex-direction: column; padding: 1rem 24px; gap: 0; }
    .main-nav li { border-bottom: 1px solid var(--color-border); }
    .main-nav a { display: block; padding: 0.9rem 0; }
    .main-nav a::after { display: none; }
    .hero { min-height: auto; padding-bottom: 60px; }
    .hero-decor { display: none; }
    .hero-tabs-nav { gap: 0.4rem; }
    .hero-tabs-nav button { padding: 0.5rem 0.9rem; font-size: 0.8rem; }
    .footer-inner { grid-template-columns: 1fr; text-align: center; }
    .stats-row { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 480px) {
    .hero-cta { flex-direction: column; }
    .hero-cta .btn { width: 100%; }
    .stats-row { grid-template-columns: 1fr; }
}