:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --secondary: #64748b;
    --background: #f3f4f6;
    --surface: #ffffff;
    --text: #1f2937;
    --text-light: #6b7280;
    --border: #e5e7eb;
    --danger: #ef4444;
    --success: #10b981;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: var(--background);
    color: var(--text);
    margin: 0;
    padding: 0;
    line-height: 1.5;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    border: none;
    text-decoration: none;
}

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

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

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

.btn-outline:hover {
    background-color: var(--border);
}

.card {
    background-color: var(--surface);
    border-radius: 1rem;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
}

.input-group {
    margin-bottom: 1rem;
}

.input-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--text-light);
}

.form-control {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border);
    border-radius: 0.5rem;
    font-size: 1rem;
    transition: border-color 0.2s;
}

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

/* Navbar */
.navbar {
    background-color: var(--surface);
    border-bottom: 1px solid var(--border);
    padding: 1rem 0;
    margin-bottom: 2rem;
}

.navbar-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary);
    text-decoration: none;
}

.nav-links a {
    color: var(--text-light);
    text-decoration: none;
    margin-left: 1.5rem;
    font-weight: 500;
}

.nav-links a:hover {
    color: var(--primary);
}

/* Drag & Drop Zone */
.upload-zone {
    border: 2px dashed var(--border);
    border-radius: 1rem;
    padding: 3rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.2s;
    background-color: #f9fafb;
}

.upload-zone.dragover {
    border-color: var(--primary);
    background-color: #eff6ff;
}

.upload-zone p {
    color: var(--text-light);
    margin-top: 1rem;
}

/* Table */
.table-container {
    overflow-x: auto;
}

table {
    width: 100%;
    border-collapse: collapse;
}

th, td {
    padding: 0.75rem 1rem;
    text-align: left;
    border-bottom: 1px solid var(--border);
}

th {
    background-color: #f9fafb;
    font-weight: 600;
    color: var(--text-light);
}

/* Utilities */
.text-center { text-align: center; }
.mt-4 { margin-top: 1rem; }
.mb-4 { margin-bottom: 1rem; }
.hidden { display: none; }