:root {
    --primary: #00f2fe;
    --secondary: #4facfe;
    --dark-bg: #0b0f19;
    --glass-bg: rgba(18, 24, 43, 0.6);
    --glass-border: rgba(255, 255, 255, 0.08);
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --accent: #3b82f6;
    --input-bg: rgba(15, 23, 42, 0.8);
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--dark-bg);
    color: var(--text-main);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow-x: hidden;
    position: relative;
    padding: 2rem 0;
}

.background-effects {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: -1;
    overflow: hidden;
}

.glow {
    position: absolute;
    border-radius: 50%;
    filter: blur(120px);
    opacity: 0.4;
    animation: drift 15s infinite alternate;
}

.glow-1 {
    top: -10%;
    right: -5%;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, #3b82f6, transparent 70%);
}

.glow-2 {
    bottom: -10%;
    left: -10%;
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, #8b5cf6, transparent 70%);
}

@keyframes drift {
    0% { transform: translateY(0) scale(1); }
    100% { transform: translateY(-50px) scale(1.1); }
}

.app-container {
    width: 100%;
    max-width: 1100px;
    padding: 2rem;
    z-index: 1;
}

header {
    text-align: center;
    margin-bottom: 3rem;
    animation: fadeInDown 0.8s ease-out;
}

header h1 {
    font-size: 3.5rem;
    font-weight: 800;
    letter-spacing: -1.5px;
    margin-bottom: 0.5rem;
}

header h1 span {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

header p {
    color: var(--text-muted);
    font-size: 1.1rem;
    max-width: 600px;
    margin: 0 auto;
}

.calculator-grid {
    display: grid;
    grid-template-columns: 1fr 400px;
    gap: 2rem;
    align-items: start;
}

@media(max-width: 900px) {
    .calculator-grid {
        grid-template-columns: 1fr;
    }
}

.glass-panel {
    background: var(--glass-bg);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--glass-border);
    border-radius: 20px;
    padding: 2.5rem;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    animation: fadeInUp 0.8s ease-out;
}

.glass-panel:hover {
    box-shadow: 0 30px 60px -12px rgba(0, 0, 0, 0.6);
}

.row-group {
    display: flex;
    gap: 1.5rem;
}

.row-group .input-block {
    flex: 1;
}

.form-group {
    margin-bottom: 1.5rem;
}

label {
    display: block;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 0.5rem;
}

select, input[type="number"], input[type="text"], input[type="password"] {
    width: 100%;
    padding: 0.85rem 1rem;
    background: var(--input-bg);
    border: 1px solid rgba(255,255,255,0.1);
    border-radius: 10px;
    color: #fff;
    font-size: 1rem;
    font-family: 'Inter', sans-serif;
    outline: none;
    transition: border-color 0.3s, box-shadow 0.3s;
    appearance: none;
    -webkit-appearance: none;
}

select:focus, input:focus {
    border-color: var(--secondary);
    box-shadow: 0 0 0 3px rgba(79, 172, 254, 0.2);
}

select {
    cursor: pointer;
    background-image: url("data:image/svg+xml;charset=UTF-8,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='white' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3e%3cpolyline points='6 9 12 15 18 9'%3e%3c/polyline%3e%3c/svg%3e");
    background-repeat: no-repeat;
    background-position: right 1rem center;
    background-size: 1em;
}

.section-divider {
    margin: 2rem 0 1rem;
    text-transform: uppercase;
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--text-muted);
    border-bottom: 1px solid rgba(255,255,255,0.1);
    padding-bottom: 0.5rem;
}

.os-selector {
    display: flex;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.radio-label {
    flex: 1;
    cursor: pointer;
    position: relative;
    margin: 0;
}

.radio-label input {
    position: absolute;
    opacity: 0;
}

.custom-radio {
    display: block;
    text-align: center;
    padding: 0.85rem;
    background: var(--input-bg);
    border: 1px solid rgba(255,255,255,0.1);
    border-radius: 10px;
    transition: all 0.3s ease;
    font-weight: 500;
}

.radio-label input:checked + .custom-radio {
    background: rgba(59, 130, 246, 0.2);
    border-color: var(--accent);
    color: #fff;
    box-shadow: 0 0 10px rgba(59, 130, 246, 0.3);
}

.dynamic-section {
    display: none;
    animation: fadeIn 0.4s ease-out;
}

.dynamic-section.active {
    display: block;
}

.summary-panel {
    text-align: center;
    position: sticky;
    top: 2rem;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.summary-desc {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-top: 1rem;
}

.cost-display {
    margin: 2rem 0;
    display: flex;
    justify-content: center;
    align-items: flex-start;
}

.currency {
    font-size: 2.2rem;
    font-weight: 600;
    color: var(--primary);
    margin-top: 0.4rem;
    margin-right: 0.2rem;
}

#total-cost {
    font-size: 5rem;
    font-weight: 800;
    line-height: 1;
    background: linear-gradient(135deg, #fff, #a5b4fc);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    transition: all 0.3s ease;
}

.cta-button {
    width: 100%;
    padding: 1.2rem;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border: none;
    border-radius: 12px;
    color: #0b0f19;
    font-size: 1.2rem;
    font-weight: 800;
    letter-spacing: 0.5px;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
}

.cta-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px -10px var(--primary);
}

.admin-link {
    display: inline-block;
    margin-top: 2rem;
    font-size: 0.85rem;
    color: var(--text-muted);
    text-decoration: none;
    transition: color 0.3s;
}

.admin-link:hover {
    color: #fff;
    text-decoration: underline;
}

/* Animations */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeInDown {
    from { opacity: 0; transform: translateY(-20px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Admin Panel Specifics */
.admin-items { margin-top: 2rem; }
.admin-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--input-bg);
    padding: 1rem 1.5rem;
    margin-bottom: 0.8rem;
    border-radius: 10px;
    border: 1px solid rgba(255,255,255,0.05);
    transition: transform 0.2s;
}
.admin-item:hover { transform: translateX(5px); border-color: rgba(255,255,255,0.1); }
.admin-item input { width: 120px; padding: 0.5rem; margin-right: 1.5rem; }
.btn-small {
    padding: 0.6rem 1.2rem;
    background: rgba(255,255,255,0.1);
    border: none;
    border-radius: 8px;
    color: #fff;
    cursor: pointer;
    font-weight: 600;
    transition: background 0.3s;
}
.btn-small:hover { background: rgba(255,255,255,0.2); }
.btn-delete { background: rgba(239, 68, 68, 0.2); color: #fca5a5; }
.btn-delete:hover { background: rgba(239, 68, 68, 0.4); }

.tab-buttons {
    display: flex;
    overflow-x: auto;
    gap: 0.8rem;
    margin-bottom: 2rem;
    padding-bottom: 0.5rem;
}
.tab-btn {
    white-space: nowrap;
    background: transparent;
    border: 1px solid rgba(255,255,255,0.2);
    color: var(--text-muted);
    padding: 0.6rem 1.2rem;
    border-radius: 20px;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.2s;
}
.tab-btn.active, .tab-btn:hover {
    background: var(--accent);
    color: #fff;
    border-color: var(--accent);
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3);
}
.add-new-form { display: flex; gap: 1rem; margin-top: 1.5rem; }
.add-new-form input { flex: 1; }
.add-new-form button { background: var(--accent); color: white; }