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

:root {
    --primary: #1e40af;
    --secondary: #3b82f6;
    --accent: #0ea5e9;
    --dark: #0f172a;
    --light: #f8fafc;
    --border: #e2e8f0;
    --text: #1e293b;
    --text-light: #64748b;
}

body {
    font-family: 'Inter', 'Segoe UI', sans-serif;
    line-height: 1.6;
    color: var(--text);
    background: var(--light);
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 20px;
}

/* HEADER & NAVIGATION */
.main-header {
    background: white;
    border-bottom: 2px solid var(--primary);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 0;
}

.logo-brand a {
    display: flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
    color: var(--primary);
    font-size: 22px;
    font-weight: 800;
}

.logo-brand i {
    font-size: 28px;
}

.nav-items {
    display: flex;
    list-style: none;
    gap: 5px;
    align-items: center;
}

.nav-items a {
    text-decoration: none;
    color: var(--text);
    padding: 8px 16px;
    border-radius: 6px;
    transition: all 0.2s;
    font-weight: 500;
}

.nav-items a:hover,
.nav-items a.active {
    color: white;
    background: var(--primary);
}

.lang-select {
    padding: 8px 12px;
    border: 1px solid var(--border);
    border-radius: 6px;
    background: white;
    color: var(--text);
    font-weight: 500;
    cursor: pointer;
    font-family: inherit;
}

.lang-select:hover {
    border-color: var(--primary);
}

/* HERO SECTION */
.hero {
    background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
    color: white;
    padding: 100px 0;
    position: relative;
    overflow: hidden;
}

.hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 50px;
    align-items: center;
}

.hero-content h1 {
    font-size: 48px;
    margin-bottom: 20px;
    font-weight: 800;
    line-height: 1.1;
}

.hero-content p {
    font-size: 18px;
    margin-bottom: 30px;
    opacity: 0.95;
}

.btn-primary,
.btn-secondary {
    display: inline-block;
    padding: 14px 32px;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 700;
    font-size: 16px;
    transition: all 0.3s;
    border: none;
    cursor: pointer;
}

.btn-primary {
    background: white;
    color: var(--primary);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(0,0,0,0.2);
}

.btn-secondary {
    background: var(--accent);
    color: white;
}

.btn-secondary:hover {
    background: #0284c7;
    transform: translateY(-2px);
}

.calc-icon {
    font-size: 120px;
    opacity: 0.2;
    animation: float 3s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0px); }
    50% { transform: translateY(-20px); }
}

/* FEATURES SECTION */
.features {
    padding: 80px 0;
    background: white;
}

.features h2 {
    text-align: center;
    font-size: 36px;
    margin-bottom: 50px;
    color: var(--primary);
}

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

.feature-box {
    background: var(--light);
    padding: 30px;
    border-radius: 12px;
    text-align: center;
    transition: all 0.3s;
    border: 2px solid transparent;
}

.feature-box:hover {
    border-color: var(--secondary);
    transform: translateY(-8px);
    box-shadow: 0 10px 30px rgba(59,130,246,0.15);
}

.feature-box i {
    font-size: 40px;
    color: var(--secondary);
    margin-bottom: 15px;
}

.feature-box h3 {
    font-size: 20px;
    margin-bottom: 10px;
    color: var(--primary);
}

.feature-box p {
    color: var(--text-light);
    font-size: 14px;
}

/* CTA SECTION */
.cta-section {
    background: linear-gradient(135deg, var(--primary), var(--accent));
    color: white;
    padding: 60px 0;
    text-align: center;
}

.cta-section h2 {
    font-size: 36px;
    margin-bottom: 15px;
}

.cta-section p {
    font-size: 18px;
    margin-bottom: 30px;
    opacity: 0.95;
}

/* CALCULATOR */
.calc-section {
    padding: 60px 0;
    background: white;
}

.calc-section h1 {
    text-align: center;
    font-size: 36px;
    margin-bottom: 40px;
    color: var(--primary);
}

.calc-wrapper {
    max-width: 450px;
    margin: 0 auto;
    background: white;
    border-radius: 16px;
    overflow: hidden;
    box-shadow: 0 10px 40px rgba(0,0,0,0.15);
}

.calc-display {
    background: linear-gradient(135deg, var(--primary), var(--accent));
    color: white;
    padding: 25px;
    text-align: right;
}

.calc-expr {
    font-size: 16px;
    opacity: 0.8;
    min-height: 24px;
    margin-bottom: 8px;
}

.calc-result {
    font-size: 42px;
    font-weight: 700;
    word-break: break-all;
}

.calc-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1px;
    background: var(--border);
    padding: 1px;
}

.calc-btn {
    padding: 20px;
    background: white;
    border: none;
    font-size: 18px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.15s;
    color: var(--text);
}

.calc-btn:hover {
    background: var(--light);
}

.calc-btn.op-btn {
    color: var(--primary);
    font-weight: 700;
}

.calc-btn.clear-btn {
    color: #ef4444;
}

.calc-btn.equal-btn {
    background: var(--primary);
    color: white;
    font-weight: 700;
}

.calc-btn.equal-btn:hover {
    background: #1d3a9f;
}

.calc-btn.zero-btn {
    grid-column: span 2;
}

/* ABOUT & CONTACT */
.about-hero,
.contact-section {
    background: linear-gradient(135deg, var(--primary), var(--accent));
    color: white;
    padding: 60px 0;
    text-align: center;
}

.about-hero h1,
.contact-section h1 {
    font-size: 40px;
    margin-bottom: 10px;
}

.about-hero p,
.contact-section > .container > p {
    font-size: 18px;
    opacity: 0.9;
}

.about-content {
    padding: 60px 0;
    background: white;
}

.about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 50px;
}

.about-text h2,
.about-values h2 {
    font-size: 28px;
    margin-bottom: 20px;
    color: var(--primary);
}

.about-text p {
    margin-bottom: 18px;
    color: var(--text-light);
    line-height: 1.8;
}

.value-item {
    background: var(--light);
    padding: 20px;
    border-radius: 10px;
    margin-bottom: 15px;
    border-left: 4px solid var(--secondary);
}

.value-item h3 {
    color: var(--primary);
    margin-bottom: 8px;
}

.value-item p {
    color: var(--text-light);
    font-size: 14px;
    margin: 0;
}

/* CONTACT FORM */
.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    padding: 40px 0;
    background: white;
}

.contact-info h2,
.contact-form h2 {
    font-size: 24px;
    margin-bottom: 15px;
    color: var(--primary);
}

.contact-info p,
.contact-form > p {
    color: var(--text-light);
    margin-bottom: 30px;
}

.info-items {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.info-item {
    display: flex;
    gap: 15px;
}

.info-item i {
    font-size: 24px;
    color: var(--secondary);
    min-width: 30px;
}

.info-item h3 {
    color: var(--primary);
    margin-bottom: 5px;
}

.info-item p {
    color: var(--text-light);
    font-size: 14px;
    margin: 0;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    color: var(--text);
    font-weight: 600;
    font-size: 14px;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 12px 15px;
    border: 2px solid var(--border);
    border-radius: 8px;
    font-family: inherit;
    font-size: 14px;
    transition: border-color 0.2s;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary);
}

.form-group textarea {
    resize: vertical;
}

.btn-submit {
    width: 100%;
    padding: 12px;
    background: var(--primary);
    color: white;
    border: none;
    border-radius: 8px;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.2s;
}

.btn-submit:hover {
    background: #1d3a9f;
    transform: translateY(-2px);
}

.form-success {
    padding: 15px;
    background: #dcfce7;
    color: #166534;
    border-radius: 8px;
    text-align: center;
    font-weight: 600;
    margin-top: 15px;
}

/* FOOTER */
.footer {
    background: var(--dark);
    color: white;
    padding: 50px 0 20px;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 40px;
    margin-bottom: 40px;
}

.footer-col h4 {
    font-size: 16px;
    margin-bottom: 15px;
    color: #f1f5f9;
}

.footer-col p {
    color: #94a3b8;
    font-size: 14px;
    line-height: 1.8;
}

.footer-col ul {
    list-style: none;
}

.footer-col ul li {
    margin-bottom: 8px;
}

.footer-col ul a {
    color: #94a3b8;
    text-decoration: none;
    font-size: 14px;
    transition: color 0.2s;
}

.footer-col ul a:hover {
    color: var(--accent);
}

.footer-bottom {
    text-align: center;
    padding-top: 20px;
    border-top: 1px solid #1e293b;
    color: #64748b;
    font-size: 13px;
}

/* COOKIES */
.cookie-notice {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--dark);
    color: white;
    padding: 20px;
    z-index: 1000;
    display: none;
    border-top: 2px solid var(--primary);
}

.cookie-notice.show {
    display: block;
}

.cookie-box {
    max-width: 1100px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 20px;
}

.cookie-box p {
    color: #cbd5e1;
    font-size: 14px;
    margin: 0;
}

.cookie-box a {
    color: var(--accent);
}

.btn-accept {
    padding: 8px 20px;
    background: var(--primary);
    color: white;
    border: none;
    border-radius: 6px;
    font-weight: 600;
    cursor: pointer;
    white-space: nowrap;
    transition: all 0.2s;
}

.btn-accept:hover {
    background: #1d3a9f;
}

/* RESPONSIVE */
@media (max-width: 768px) {
    .hero .container,
    .about-grid,
    .contact-grid {
        grid-template-columns: 1fr;
    }

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

    .calc-icon {
        font-size: 80px;
    }

    .nav-items {
        gap: 0;
    }

    .nav-items a {
        padding: 6px 10px;
        font-size: 13px;
    }

    .cookie-box {
        flex-direction: column;
        align-items: flex-start;
    }
}