@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&display=swap');

:root {
    --primary: #2563eb;
    --primary-hover: #1d4ed8;
    --bg-main: #f8fafc;
    --bg-card: #ffffff;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --border-color: #e2e8f0;
    --success: #10b981;
    --danger: #ef4444;
    --info: #3b82f6;
    
    --color-a: #1e40af;
    --color-b: #047857;
    --color-c: #15803d;
    --color-d: #b45309;
    --color-e: #92400e;
    --color-f: #b91c1c;
    --color-fx: #991b1b;

    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --radius-lg: 12px;
    --radius-md: 8px;
    
    --transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background-color: var(--bg-main);
    color: var(--text-primary);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: 1200px;
    margin: 2rem auto;
    padding: 0 1.5rem;
}

header {
    text-align: center;
    margin-bottom: 2.5rem;
}

header h1 {
    font-size: 1.875rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

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

#upload-zone {
    background: var(--bg-card);
    border: 2px dashed var(--border-color);
    border-radius: var(--radius-lg);
    padding: 3rem 2rem;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    margin-bottom: 2rem;
    box-shadow: var(--shadow-sm);
}

#upload-zone:hover {
    border-color: var(--primary);
    background: #f1f5f9;
}

#upload-zone.drag-over {
    border-color: var(--primary);
    background: #eff6ff;
    transform: scale(1.01);
}

#upload-zone i {
    font-size: 3rem;
    color: var(--primary);
    margin-bottom: 1rem;
    display: block;
}

#upload-zone h3 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

#upload-zone p {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

#config-zone {
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    margin-bottom: 2rem;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
}

.config-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.25rem;
    margin-bottom: 1.5rem;
}

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

.input-group label {
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
}

input[type="number"], input[type="text"] {
    padding: 0.625rem 0.875rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    transition: var(--transition);
    width: 100%;
}

input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.625rem 1.25rem;
    font-size: 0.875rem;
    font-weight: 600;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: var(--transition);
    border: none;
}

.btn-primary {
    background: var(--primary);
    color: white;
}

.btn-primary:hover {
    background: var(--primary-hover);
    transform: translateY(-1px);
}

.btn-outline {
    background: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
}

.btn-outline:hover {
    background: #f8fafc;
    border-color: var(--text-secondary);
}

#results-zone {
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--border-color);
}

.table-container {
    overflow-x: auto;
}

table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.8125rem;
}

th {
    background: #f1f5f9;
    padding: 0.75rem 1rem;
    text-align: left;
    font-weight: 600;
    color: var(--text-secondary);
    border-bottom: 1px solid var(--border-color);
    white-space: nowrap;
}

td {
    padding: 0.75rem 1rem;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-primary);
}

tr:last-child td {
    border-bottom: none;
}

tr:hover td {
    background-color: #f8fafc;
}

.text-center { text-align: center; }

.ects-a { color: var(--color-a); font-weight: 600; }
.ects-b { color: var(--color-b); font-weight: 600; }
.ects-c { color: var(--color-c); font-weight: 600; }
.ects-d { color: var(--color-d); font-weight: 600; }
.ects-e { color: var(--color-e); font-weight: 600; }
.ects-f { color: var(--color-f); font-weight: 600; }
.ects-fx { color: var(--color-fx); font-weight: 600; }

.summary-val { font-weight: 700; color: var(--text-primary); }

.footer-actions {
    padding: 1.5rem;
    display: flex;
    justify-content: flex-end;
}

#error-zone {
    background: #fef2f2;
    border: 1px solid #fee2e2;
    color: var(--danger);
    padding: 1rem;
    border-radius: var(--radius-md);
    margin-top: 1rem;
    font-size: 0.875rem;
    display: none;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: var(--bg-card);
    padding: 1.25rem;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    text-align: center;
    box-shadow: var(--shadow-sm);
}

.stat-card .label {
    font-size: 0.75rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 0.5rem;
    display: block;
}

.stat-card .value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary);
}

.info-section {
    background: #f1f5f9;
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    margin-bottom: 2rem;
    border: 1px solid var(--border-color);
}

.info-section h3 {
    font-size: 1rem;
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

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

.info-item h4 {
    font-size: 0.875rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.info-item p, .info-item li {
    font-size: 0.8125rem;
    color: var(--text-secondary);
    line-height: 1.4;
}

.info-item ul {
    padding-left: 1.25rem;
    margin-top: 0.5rem;
}

#loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(4px);
    display: none;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid #e2e8f0;
    border-top: 3px solid var(--primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: 1rem;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

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

@media print {
    @page {
        margin: 10mm;
    }
    body {
        background: white !important;
        padding: 0 !important;
        margin: 0 !important;
    }
    header, .info-section, #upload-zone, #config-zone, #group-stats, .footer-actions, footer, #loading-overlay, #error-zone {
        display: none !important;
    }
    .container {
        max-width: 100% !important;
        padding: 0 !important;
        margin: 0 !important;
    }
    main {
        margin: 0 !important;
        padding: 0 !important;
    }
    #results-zone {
        display: block !important;
        box-shadow: none !important;
        border: none !important;
        padding: 0 !important;
        margin: 0 !important;
    }
    .table-container {
        overflow: visible !important;
    }
    table {
        border-collapse: collapse !important;
        width: 100% !important;
        border: 1pt solid #000 !important;
    }
    th, td {
        border: 1pt solid #000 !important;
        color: #000 !important;
        padding: 4pt 6pt !important;
        background: transparent !important;
    }
    th {
        font-weight: 600 !important;
    }
    .text-center {
        text-align: center !important;
    }
    .ects-a, .ects-b, .ects-c, .ects-d, .ects-e, .ects-f, .ects-fx, .summary-val {
        color: #000 !important;
        font-weight: 400 !important;
    }
}

.fade-in {
    animation: fadeIn 0.3s ease-out forwards;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    border: 0;
}