/* --- 1. GLOBAL RESETS & FONTS --- */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background: linear-gradient(135deg, #0b2512 0%, #020c04 100%);
    color: #e2e8f0;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

/* --- 2. GLOBAL CONTAINER CAARD --- */
.container, .card, .calculator {
    text-align: center;
    padding: 2.5rem;
    border: 1px solid #10b981;
    border-radius: 12px;
    background-color: rgba(10, 25, 14, 0.85);
    box-shadow: 0 8px 32px 0 rgba(16, 185, 129, 0.15);
    backdrop-filter: blur(6px);
    width: 100%;
    max-width: 450px; /* Standard single-card layout width */
}

/* --- 3. HEADINGS & TEXT --- */
h1, h2, h3 {
    color: #39ff14;
    text-shadow: 0 0 10px rgba(57, 255, 20, 0.4);
    letter-spacing: 1px;
    margin-bottom: 1rem;
}

h1 { font-size: 2.8rem; }
h2 { font-size: 2rem; }

p {
    color: #cbd5e1;
    font-size: 1rem;
    text-transform: uppercase;
    letter-spacing: 2px;
    line-height: 1.5;
    margin-bottom: 1.5rem;
}

/* --- 4. BUTTONS --- */
button, .btn {
    background: rgba(16, 185, 129, 0.1);
    color: #39ff14;
    border: 1px solid #10b981;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: bold;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.3s ease;
    letter-spacing: 1px;
    text-transform: uppercase;
}

/* Button Hover State (Neon Glow Effect) */
button:hover, .btn:hover {
    background: #10b981;
    color: #020c04;
    box-shadow: 0 0 15px rgba(16, 185, 129, 0.6);
    transform: translateY(-2px);
}

/* Button Click/Active State */
button:active, .btn:active {
    transform: translateY(0);
}

/* --- 5. INPUT FIELDS & TEXTAREAS --- */
input[type="text"], input[type="number"], input[type="password"], textarea, select {
    width: 100%;
    background: rgba(2, 12, 4, 0.6);
    border: 1px solid rgba(16, 185, 129, 0.4);
    padding: 0.75rem;
    color: #e2e8f0;
    font-size: 1.1rem;
    border-radius: 6px;
    outline: none;
    transition: all 0.3s ease;
    margin-bottom: 1rem;
}

/* Input Focus State */
input:focus, textarea:focus, select:focus {
    border-color: #39ff14;
    box-shadow: 0 0 10px rgba(57, 255, 20, 0.3);
}

/* --- 6. LINKS --- */
a {
    color: #39ff14;
    text-decoration: none;
    transition: color 0.3s ease;
}

a:hover {
    text-decoration: underline;
    text-shadow: 0 0 5px rgba(57, 255, 20, 0.5);
}
    margin: 0;
    text-transform: uppercase;
    letter-spacing: 2px;
}