:root {
    --bg: #f5f7fb;
    --card-bg: #ffffff;
    --primary: #5c6ac4;
    --secondary: #8d99f2;
    --text: #2f2f47;
    --muted: #6c6c80;
    --border: #e1e5f0;
    --success: #20c997;
    --error: #f25f5c;
}

* {
    box-sizing: border-box;
}

body {
    font-family: 'Pretendard', 'Noto Sans KR', sans-serif;
    background: var(--bg);
    color: var(--text);
    margin: 0;
}

.auth-page {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
}

.auth-container {
    background: var(--card-bg);
    padding: 3rem;
    border-radius: 1.5rem;
    width: min(420px, 90vw);
    box-shadow: 0 25px 40px rgba(76, 80, 120, 0.1);
    text-align: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 0.75rem;
}

.auth-form {
    display: grid;
    gap: 0.75rem;
    text-align: left;
}

.auth-form label {
    font-weight: 600;
    color: var(--muted);
}

.auth-form input {
    padding: 0.75rem 1rem;
    border-radius: 0.75rem;
    border: 1px solid var(--border);
    font-size: 1rem;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.4rem;
    padding: 0.75rem 1.25rem;
    border-radius: 999px;
    border: none;
    background: var(--secondary);
    color: white;
    font-weight: 600;
    cursor: pointer;
    text-decoration: none;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.btn.primary {
    background: linear-gradient(135deg, #5c6ac4, #8d99f2);
    box-shadow: 0 15px 25px rgba(92, 106, 196, 0.3);
}

.btn.secondary {
    background: #ff9f1c;
    box-shadow: 0 10px 20px rgba(255, 159, 28, 0.25);
}

.btn:hover {
    transform: translateY(-2px);
}

.alert {
    padding: 0.75rem 1rem;
    border-radius: 1rem;
    margin-bottom: 1rem;
    font-weight: 600;
}

.alert-success {
    background: rgba(32, 201, 151, 0.15);
    color: var(--success);
}

.alert-error {
    background: rgba(242, 95, 92, 0.15);
    color: var(--error);
}

.alert ul {
    padding-left: 1rem;
    margin: 0.5rem 0 0;
}

.auth-switch {
    margin-top: 1.25rem;
    color: var(--muted);
}

.app-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1.5rem 3rem;
    background: var(--card-bg);
    box-shadow: 0 10px 25px rgba(76, 80, 120, 0.08);
    position: sticky;
    top: 0;
    z-index: 10;
}

.brand {
    font-size: 1.25rem;
    font-weight: 700;
}

.user-chip {
    background: rgba(92, 106, 196, 0.12);
    padding: 0.5rem 1rem;
    border-radius: 999px;
    margin-right: 1rem;
    font-weight: 600;
    color: var(--primary);
}

.container {
    width: min(1100px, 92vw);
    margin: 2rem auto 4rem;
    display: grid;
    gap: 2rem;
}

.card {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 1.5rem;
    box-shadow: 0 25px 40px rgba(76, 80, 120, 0.08);
}

.upload-card p, .list-card p {
    color: var(--muted);
}

.upload-form {
    display: grid;
    gap: 0.75rem;
    margin-top: 1rem;
}

.upload-form input[type="text"],
.upload-form input[type="file"] {
    padding: 0.75rem 1rem;
    border: 1px solid var(--border);
    border-radius: 1rem;
}

.data-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 1rem;
}

.data-table thead {
    background: rgba(92, 106, 196, 0.08);
}

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

.data-table tbody tr:hover {
    background: rgba(92, 106, 196, 0.05);
}

.empty-state {
    color: var(--muted);
    font-style: italic;
}

.analysis-container .card h2 {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
}

.section-desc {
    color: var(--muted);
    margin-top: 0;
}

.chart-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
}

.metric-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 1rem;
    margin-top: 1.5rem;
}

.metric-card {
    background: linear-gradient(135deg, rgba(92, 106, 196, 0.12), rgba(141, 153, 242, 0.12));
    border-radius: 1.25rem;
    padding: 1.25rem;
    display: grid;
    gap: 0.35rem;
    text-align: left;
}

.metric-icon {
    font-size: 1.5rem;
}

.metric-label {
    color: var(--muted);
    font-weight: 600;
}

.metric-value {
    font-size: 1.35rem;
    font-weight: 700;
}

.data-table.compact th,
.data-table.compact td {
    padding: 0.5rem 0.75rem;
}

.subheading {
    margin-top: 2rem;
}

@media (max-width: 768px) {
    .app-header {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }

    .container {
        width: 94vw;
    }
}