:root {
    --bg-color: #f4f7f6;
    --card-bg: #ffffff;
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --text-color: #1f2937;
    --text-muted: #6b7280;
    --border-color: #e5e7eb;
    --success-color: #10b981;
    --danger-color: #ef4444;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.container {
    width: 100%;
    max-width: 600px;
    margin: 40px auto;
    padding: 0 20px;
    flex-grow: 1;
}

.container-lg {
    max-width: 1000px;
}

.header {
    text-align: center;
    margin-bottom: 30px;
}

.header h1 {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 10px;
}

.header p {
    color: var(--text-muted);
}

.card {
    background-color: var(--card-bg);
    border-radius: 12px;
    padding: 30px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    border: 1px solid var(--border-color);
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
}

.form-control {
    width: 100%;
    padding: 12px 15px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.2s;
}

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

.btn {
    display: inline-block;
    width: 100%;
    padding: 12px 20px;
    background-color: var(--primary-color);
    color: #fff;
    border: none;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s, transform 0.1s;
    text-decoration: none;
    text-align: center;
}

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

.btn:active {
    transform: scale(0.98);
}

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

.btn-secondary:hover {
    background-color: #e5e7eb;
}

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

.btn-danger:hover {
    background-color: #dc2626;
}

.btn-sm {
    padding: 6px 12px;
    font-size: 0.9rem;
    width: auto;
}

.hidden {
    display: none !important;
}

.result-box {
    margin-top: 30px;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
    text-align: center;
}

.result-box h3 {
    margin-bottom: 15px;
}

.short-url-display {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    margin-bottom: 20px;
}

.short-url-display a {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--primary-color);
    text-decoration: none;
    word-break: break-all;
}

.short-url-display a:hover {
    text-decoration: underline;
}

.btn-copy {
    padding: 8px 12px;
    font-size: 0.9rem;
    width: auto;
    background-color: var(--bg-color);
    color: var(--text-color);
    border: 1px solid var(--border-color);
}

.btn-copy:hover {
    background-color: #e5e7eb;
}

#qrcode {
    display: flex;
    justify-content: center;
    margin: 20px 0;
}

.alert {
    padding: 12px;
    border-radius: 8px;
    margin-bottom: 20px;
    text-align: center;
}

.alert-error {
    background-color: #fef2f2;
    color: var(--danger-color);
    border: 1px solid #f87171;
}

.alert-success {
    background-color: #ecfdf5;
    color: var(--success-color);
    border: 1px solid #34d399;
}

.options-toggle {
    text-align: center;
    margin: 15px 0;
}

.options-toggle a {
    color: var(--primary-color);
    text-decoration: none;
    font-size: 0.9rem;
}

.options-toggle a:hover {
    text-decoration: underline;
}

/* Stats table */
.stats-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 20px;
    font-size: 0.9rem;
}

.stats-table th, .stats-table td {
    padding: 12px;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

.stats-table th {
    font-weight: 600;
    color: var(--text-muted);
}