:root {
    --bg-dark: #0f172a;
    --bg-panel: rgba(30, 41, 59, 0.7);
    --border-color: rgba(255, 255, 255, 0.1);
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --accent-1: #3b82f6;
    --accent-2: #8b5cf6;
    --success: #10b981;
    --danger: #ef4444;
}

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

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

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

.blob {
    position: absolute;
    filter: blur(100px);
    opacity: 0.5;
    border-radius: 50%;
    animation: float 20s infinite alternate ease-in-out;
}

.blob-1 {
    width: 400px;
    height: 400px;
    background: var(--accent-1);
    top: -100px;
    left: -100px;
}

.blob-2 {
    width: 500px;
    height: 500px;
    background: var(--accent-2);
    bottom: -150px;
    right: -100px;
    animation-delay: -10s;
}

@keyframes float {
    0% { transform: translate(0, 0) scale(1); }
    100% { transform: translate(50px, 50px) scale(1.1); }
}

/* Layout Container */
.container {
    width: 100%;
    max-width: 900px;
    z-index: 1;
}

header {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.logo-box {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, var(--accent-1), var(--accent-2));
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    box-shadow: 0 10px 25px rgba(59, 130, 246, 0.3);
}

header h1 {
    font-size: 2rem;
    font-weight: 700;
    background: linear-gradient(to right, #fff, #cbd5e1);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

header p {
    color: var(--text-secondary);
    font-size: 1rem;
}

/* Glassmorphism Panels */
.glass {
    background: var(--bg-panel);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--border-color);
    border-radius: 24px;
    padding: 2rem;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    margin-bottom: 2rem;
}

h2 {
    font-size: 1.25rem;
    margin-bottom: 1.5rem;
    color: #e2e8f0;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

h2::before {
    content: "";
    width: 4px;
    height: 20px;
    background: var(--accent-1);
    border-radius: 4px;
    display: inline-block;
}

.mt-4 { margin-top: 2rem; }

/* Forms */
.form-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.full-width {
    grid-column: 1 / -1;
}

label {
    font-size: 0.875rem;
    color: var(--text-secondary);
    font-weight: 600;
}

input, select {
    background: rgba(15, 23, 42, 0.6);
    border: 1px solid var(--border-color);
    color: white;
    padding: 0.875rem 1rem;
    border-radius: 12px;
    font-family: inherit;
    font-size: 1rem;
    transition: all 0.3s ease;
    outline: none;
}

input:focus, select:focus {
    border-color: var(--accent-1);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.2);
}

button.btn-primary {
    background: linear-gradient(135deg, var(--accent-1), var(--accent-2));
    color: white;
    border: none;
    padding: 1rem 2rem;
    font-size: 1.1rem;
    font-weight: 600;
    border-radius: 12px;
    cursor: pointer;
    width: 100%;
    margin-top: 2rem;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    font-family: inherit;
}

button.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(139, 92, 246, 0.4);
}

button.btn-primary:active {
    transform: translateY(0);
}

/* Results Panel */
.receipt-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.btn-icon {
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid var(--border-color);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 8px;
    cursor: pointer;
    font-family: inherit;
    transition: all 0.2s ease;
}

.btn-icon:hover {
    background: rgba(255, 255, 255, 0.2);
}

.receipt-body {
    background: rgba(0, 0, 0, 0.2);
    border-radius: 16px;
    padding: 2rem;
    border: 1px solid rgba(255, 255, 255, 0.05);
}

.receipt-row {
    display: flex;
    justify-content: space-between;
    padding: 0.5rem 0;
}

.info-row {
    border-bottom: 1px dashed rgba(255, 255, 255, 0.1);
}
.info-row:last-of-type { border-bottom: none; }

.label {
    color: var(--text-secondary);
}

.value {
    font-weight: 600;
    text-align: right;
}

.highlight-val {
    color: var(--accent-1);
    font-size: 1.1rem;
}

hr {
    border: 0;
    height: 1px;
    background: rgba(255, 255, 255, 0.1);
    margin: 1.5rem 0;
}

/* ── Tariff Period Card ─────────────────────────── */
.period-card {
    position: relative;
    background: linear-gradient(135deg, rgba(30,41,59,0.9), rgba(15,23,42,0.95));
    border: 1px solid rgba(255,255,255,0.1);
    border-radius: 16px;
    padding: 1.25rem 1.5rem 1.25rem 1.5rem;
    margin-bottom: 1.25rem;
    overflow: hidden;
    animation: cardIn 0.4s ease both;
    box-shadow: 0 8px 32px rgba(0,0,0,0.35);
}

.period-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--accent-1), var(--accent-2));
}

.period-card:nth-child(even)::before {
    background: linear-gradient(90deg, #10b981, #3b82f6);
}

@keyframes cardIn {
    from { opacity: 0; transform: translateY(10px); }
    to   { opacity: 1; transform: translateY(0); }
}

.slab-header {
    font-size: 0.95rem;
    color: #e2e8f0;
    margin-bottom: 1rem;
    font-weight: 700;
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 0.25rem;
}

.slab-header .period-badge {
    background: linear-gradient(135deg, var(--accent-1), var(--accent-2));
    color: white;
    font-size: 0.72rem;
    font-weight: 700;
    padding: 0.2rem 0.65rem;
    border-radius: 20px;
    white-space: nowrap;
    letter-spacing: 0.03em;
    margin-top: 2px;
}

.slab-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.85rem;
    color: #cbd5e1;
    padding: 0.3rem 0;
    padding-left: 0;
}

.total-row {
    font-size: 1.1rem;
}

.grand-total-box {
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.1), rgba(139, 92, 246, 0.1));
    border: 1px solid var(--accent-1);
    border-radius: 12px;
    padding: 1.5rem;
    text-align: center;
}

.grand-total-box h3 {
    color: var(--text-secondary);
    font-size: 1rem;
    margin-bottom: 0.5rem;
}

.grand-total-box .amount {
    font-size: 2.5rem;
    font-weight: 700;
    color: white;
}

/* Error Toast */
.error-msg {
    color: var(--danger);
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.3);
    padding: 1rem;
    border-radius: 8px;
    margin-bottom: 1rem;
    display: none;
}

/* Print styles */
@media print {
    body { background: white; color: black; padding: 0; }
    .background-effects, .input-panel, header, #printBtn, #pdfBtn { display: none !important; }
    .results-panel { box-shadow: none; border: none; }
    .glass { backdrop-filter: none; background: white; border: none; }
    .receipt-body { background: white; border: 1px solid #ccc; }
    .label { color: #555; }
    .slab-header { color: #333; }
    .period-card { background: #f9fafb; border: 1px solid #e2e8f0; box-shadow: none; }
    .period-card::before { background: #3b82f6; }
    .grand-total-box { background: #f0f0f0; border: 1px solid #ccc; }
    .grand-total-box .amount, .highlight-val { color: black; }
    .value, .slab-row { color: black; }
    #subDivisionHeaderBlock { border-color: #e5e7eb !important; }
    #outSubDivision { color: #1e3a8a !important; text-shadow: none !important; }
    details > :not(summary) { display: block !important; }
    details summary { display: none !important; }
}

@media (max-width: 600px) {
    .receipt-row { flex-direction: column; gap: 0.25rem; }
    .value { text-align: left; }
}

/* PDF Export Styles */
.pdf-mode {
    background: white !important;
    color: black !important;
    padding: 2rem !important;
    border: none !important;
}
.pdf-mode .period-card { background: #f9fafb !important; border: 1px solid #e2e8f0 !important; box-shadow: none !important; }
.pdf-mode .period-card::before { background: #3b82f6 !important; }
.pdf-mode .label, .pdf-mode .slab-header { color: #333 !important; }
.pdf-mode .period-badge { background: #3b82f6 !important; color: white !important; }
.pdf-mode .grand-total-box { background: #f0f0f0 !important; border: 1px solid #ccc !important; }
.pdf-mode .grand-total-box .amount, .pdf-mode .highlight-val { color: black !important; }
.pdf-mode .value, .pdf-mode .slab-row { color: black !important; }
.pdf-mode .slab-row { border-color: #eee !important; }
.pdf-mode span[style] { color: #555 !important; }
.pdf-mode #subDivisionHeaderBlock { border-color: #e5e7eb !important; }
.pdf-mode #outSubDivision { color: #1e3a8a !important; text-shadow: none !important; }
.pdf-mode .receipt-body { background: transparent !important; border: none !important; padding: 0 !important; }
.pdf-mode .receipt-actions { display: none !important; }
.pdf-mode details > :not(summary) { display: block !important; }
.pdf-mode details summary { display: none !important; }