* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

body {
    background-color: #f4f6f9;
    color: #1e293b;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

header {
    background-color: #0f172a;
    color: #ffffff;
    text-align: center;
    padding: 25px 15px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

header h1 {
    font-size: 1.8rem;
    letter-spacing: 0.5px;
}

header p {
    font-size: 0.95rem;
    color: #94a3b8;
    margin-top: 5px;
}

main {
    flex: 1;
    width: 100%;
    max-width: 680px;
    margin: 25px auto;
    padding: 0 15px;
}

.button-grid {
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.nav-btn {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background-color: #ffffff;
    color: #0f172a;
    text-decoration: none;
    padding: 20px 24px;
    border-radius: 12px;
    font-size: 1.2rem;
    font-weight: 600;
    border-left: 6px solid #2563eb;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.nav-btn:hover, .nav-btn:active {
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.1);
    background-color: #f8fafc;
}

.nav-btn.highlight {
    border-left-color: #f59e0b;
    background-color: #fffbeb;
}

.arrow {
    color: #2563eb;
    font-weight: bold;
}

.nav-btn.highlight .arrow {
    color: #f59e0b;
}

.content-box {
    background: #ffffff;
    padding: 25px;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
    line-height: 1.65;
}

.content-box h2 {
    margin-bottom: 12px;
    color: #0f172a;
}

.content-box h3 {
    margin-top: 20px;
    margin-bottom: 8px;
    color: #1e293b;
    font-size: 1.1rem;
}

.content-box p {
    margin-bottom: 12px;
}

.back-btn {
    display: inline-block;
    margin-bottom: 18px;
    color: #2563eb;
    text-decoration: none;
    font-weight: 600;
    font-size: 1rem;
}

.rechner-platzhalter {
    border: 2px dashed #cbd5e1;
    background-color: #f8fafc;
    padding: 40px 20px;
    text-align: center;
    border-radius: 8px;
    margin-top: 15px;
    color: #64748b;
}

.produkt-karte {
    border: 1px solid #e2e8f0;
    border-radius: 10px;
    padding: 18px;
    margin-bottom: 15px;
}

.amazon-btn {
    display: inline-block;
    margin-top: 10px;
    background-color: #ff9900;
    color: #111111;
    font-weight: bold;
    text-decoration: none;
    padding: 12px 20px;
    border-radius: 8px;
}

footer {
    background-color: #e2e8f0;
    text-align: center;
    padding: 20px 15px;
    font-size: 0.9rem;
    margin-top: 40px;
}

footer a {
    color: #334155;
    text-decoration: none;
    margin: 0 12px;
    font-weight: 500;
}

footer p {
    margin-top: 10px;
    font-size: 0.78rem;
    color: #64748b;
    max-width: 680px;
    margin-left: auto;
    margin-right: auto;
}