:root {
    --bg: #f0f4f8;
    --card: #ffffff;
    --text: #1a202c;
    --muted: #718096;
    --border: #e2e8f0;
    --primary: #38a169;
    --primary-hover: #2f855a;
    --danger: #e53e3e;
    --danger-hover: #c53030;
    --secondary: #4299e1;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    --radius: 12px;
}

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

body {
    font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.5;
    min-height: 100vh;
}

a { color: inherit; text-decoration: none; }

.header {
    background: var(--card);
    border-bottom: 1px solid var(--border);
    padding: 1rem 1.5rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    flex-wrap: wrap;
}

.header h1 {
    font-size: 1.25rem;
    font-weight: 700;
}

.header-nav {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 1.5rem 1rem;
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
}

.card {
    background: var(--card);
    border-radius: var(--radius);
    padding: 1.5rem;
    box-shadow: var(--shadow);
}

.card h2 {
    font-size: 1.1rem;
    margin-bottom: 1rem;
    color: var(--text);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.6rem 1.2rem;
    border-radius: 8px;
    font-size: 0.95rem;
    font-weight: 600;
    border: none;
    cursor: pointer;
    transition: background 0.15s, opacity 0.15s;
    white-space: nowrap;
}

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

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

.btn-secondary {
    background: var(--secondary);
    color: #fff;
}

.btn-secondary:hover { opacity: 0.9; }

.btn-danger {
    background: var(--danger);
    color: #fff;
    padding: 0.4rem 0.8rem;
    font-size: 0.85rem;
}

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

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

.btn-ghost:hover { background: var(--bg); }

.btn-sm {
    padding: 0.35rem 0.7rem;
    font-size: 0.8rem;
}

input[type="text"],
input[type="password"],
input[type="number"],
input[type="date"] {
    width: 100%;
    padding: 0.65rem 0.85rem;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 1rem;
    background: #fff;
}

input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(56, 161, 105, 0.15);
}

label {
    display: block;
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 0.35rem;
    color: var(--muted);
}

.form-inline {
    display: flex;
    gap: 0.75rem;
    flex-wrap: wrap;
}

.form-inline input { flex: 1; min-width: 160px; }

.form-grid {
    display: grid;
    grid-template-columns: 1fr 1fr auto;
    gap: 1rem;
    align-items: end;
}

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

.alert {
    padding: 0.75rem 1rem;
    border-radius: 8px;
    margin-top: 0.75rem;
    font-size: 0.9rem;
}

.alert-error {
    background: #fff5f5;
    color: var(--danger);
    border: 1px solid #fed7d7;
}

.hidden { display: none !important; }

.muted { color: var(--muted); font-size: 0.9rem; }

.participants-list {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.participant-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    padding: 1rem;
    border: 1px solid var(--border);
    border-radius: 8px;
    transition: border-color 0.15s;
}

.participant-item:hover { border-color: var(--primary); }

.participant-info { flex: 1; min-width: 0; }

.participant-name {
    font-weight: 700;
    font-size: 1.05rem;
}

.participant-stats {
    font-size: 0.85rem;
    color: var(--muted);
    margin-top: 0.2rem;
}

.change-negative { color: var(--primary); font-weight: 600; }
.change-positive { color: var(--danger); font-weight: 600; }
.change-neutral { color: var(--muted); }

.participant-actions {
    display: flex;
    gap: 0.5rem;
    flex-shrink: 0;
}

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

table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.95rem;
}

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

th {
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.03em;
    color: var(--muted);
    font-weight: 600;
}

.chart-wrap {
    position: relative;
    height: 280px;
}

.chart-wrap-lg { height: 400px; }

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
    gap: 0.75rem;
}

.stat-item {
    background: var(--bg);
    border-radius: 8px;
    padding: 1rem 0.75rem;
    text-align: center;
    border: 1px solid var(--border);
}

.stat-value {
    font-size: 1.35rem;
    font-weight: 700;
    line-height: 1.2;
}

.stat-label {
    font-size: 0.72rem;
    color: var(--muted);
    margin-top: 0.35rem;
    line-height: 1.3;
}

.stat-value.stat-loss { color: var(--primary); }
.stat-value.stat-gain { color: var(--danger); }
.stat-value.stat-neutral { color: var(--text); }

.login-page {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    padding: 1rem;
}

.login-card {
    background: var(--card);
    border-radius: var(--radius);
    padding: 2.5rem 2rem;
    box-shadow: var(--shadow);
    width: 100%;
    max-width: 360px;
    text-align: center;
}

.login-card h1 {
    font-size: 2rem;
    color: var(--primary);
}

.login-card .subtitle {
    color: var(--muted);
    margin-bottom: 1.5rem;
}

.login-card form {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    text-align: left;
}

.login-card .btn { width: 100%; margin-top: 0.5rem; }

@media (max-width: 600px) {
    .form-grid {
        grid-template-columns: 1fr;
    }

    .participant-item {
        flex-direction: column;
        align-items: flex-start;
    }

    .participant-actions {
        width: 100%;
    }

    .participant-actions .btn {
        flex: 1;
    }
}