:root {
    --bg: #09111f;
    --bg-soft: #0f1b2d;
    --card: #16243a;
    --text: #f8fafc;
    --muted: #94a3b8;
    --primary: #22d3bd;
    --primary-glow: rgba(34, 211, 189, 0.2);
    --secondary: #10b981;
    --accent: #f59e0b;
    --border: rgba(255, 255, 255, 0.08);
    --radius-lg: 24px;
    --radius-md: 16px;
    --radius-sm: 12px;
    --shadow-xl: 0 20px 40px rgba(0, 0, 0, 0.4);
}

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

body {
    font-family: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, sans-serif;
    color: var(--text);
    background: var(--bg);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
}

.container {
    width: 100%;
    max-width: 800px;
    margin: 0 auto;
    padding: 0 24px;
}

header {
    background: rgba(9, 17, 31, 0.8);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border);
    padding: 16px 0;
    position: sticky;
    top: 0;
    z-index: 100;
}

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

.logo {
    font-size: 1.25rem;
    font-weight: 800;
    color: var(--primary);
    text-decoration: none;
    letter-spacing: -0.5px;
}

.nav-links a {
    color: var(--text);
    text-decoration: none;
    font-weight: 600;
    font-size: 0.9rem;
    margin-left: 24px;
    transition: color 0.2s;
}

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

.page-header {
    text-align: center;
    padding: 60px 0 40px;
}

.page-title {
    font-size: clamp(2rem, 8vw, 3rem);
    font-weight: 800;
    margin-bottom: 16px;
    line-height: 1.1;
    background: linear-gradient(135deg, #fff 0%, var(--primary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.page-subtitle {
    color: var(--muted);
    font-size: 1.1rem;
    max-width: 600px;
    margin: 0 auto;
}

.calculator-container {
    background: var(--card);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border);
    padding: 40px;
    box-shadow: var(--shadow-xl);
    margin-bottom: 48px;
    position: relative;
    overflow: hidden;
}

.calculator-container::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: linear-gradient(90deg, var(--primary), var(--secondary));
}

.calculator-card h2 {
    font-size: 1.5rem;
    margin-bottom: 24px;
    text-align: center;
    color: #fff;
}

.form-group {
    margin-bottom: 24px;
}

.form-group label {
    display: block;
    margin-bottom: 10px;
    font-weight: 600;
    font-size: 0.95rem;
    color: var(--text);
}

.form-group input, .form-group select {
    width: 100%;
    padding: 16px;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    color: var(--text);
    font-family: inherit;
    font-size: 1rem;
    transition: all 0.3s;
    outline: none;
}

.form-group input:focus {
    border-color: var(--primary);
    background: rgba(255, 255, 255, 0.08);
    box-shadow: 0 0 0 4px var(--primary-glow);
}

.btn-calculate {
    width: 100%;
    padding: 18px;
    background: var(--primary);
    color: var(--bg);
    border: none;
    border-radius: var(--radius-sm);
    font-weight: 800;
    font-size: 1.1rem;
    cursor: pointer;
    transition: all 0.3s;
    margin-top: 8px;
    box-shadow: 0 4px 12px rgba(34, 211, 189, 0.3);
}

.btn-calculate:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(34, 211, 189, 0.4);
    filter: brightness(1.1);
}

.result-box {
    background: rgba(34, 211, 189, 0.05);
    border: 1px solid rgba(34, 211, 189, 0.15);
    border-radius: var(--radius-md);
    padding: 32px;
    margin-top: 32px;
    text-align: center;
    transition: all 0.3s;
}

.result-box.active {
    background: rgba(34, 211, 189, 0.1);
    border-color: var(--primary);
    transform: scale(1.02);
}

.result-label {
    display: block;
    font-size: 0.9rem;
    color: var(--muted);
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 8px;
}

.result-value {
    display: block;
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--primary);
    line-height: 1;
}

.info-content {
    margin-top: 60px;
    padding-bottom: 60px;
}

.info-card {
    background: var(--bg-soft);
    border-radius: var(--radius-lg);
    padding: 40px;
    border: 1px solid var(--border);
}

.info-card h3 {
    font-size: 1.75rem;
    margin-bottom: 24px;
    color: #fff;
}

.info-card h4 {
    font-size: 1.25rem;
    margin: 32px 0 16px;
    color: var(--primary);
}

.info-card p {
    margin-bottom: 20px;
    color: var(--muted);
}

.info-card ul {
    margin: 0 0 24px 24px;
    color: var(--muted);
}

.info-card li {
    margin-bottom: 12px;
}

.back-link {
    display: inline-flex;
    align-items: center;
    color: var(--primary);
    text-decoration: none;
    font-weight: 600;
    margin-bottom: 32px;
    transition: transform 0.2s;
}

.back-link:hover {
    transform: translateX(-4px);
}

.back-link svg {
    margin-right: 8px;
}

footer {
    padding: 60px 0;
    text-align: center;
    border-top: 1px solid var(--border);
    color: var(--muted);
    font-size: 0.9rem;
}

@media (max-width: 600px) {
    .calculator-container { padding: 24px; }
    .page-header { padding: 40px 0 24px; }
    .info-card { padding: 24px; }
    .result-value { font-size: 2rem; }
}