/* ===== 青蓝+薄荷绿 主题 ===== */
:root {
    --primary: #00c6ff;      /* 青蓝 */
    --secondary: #0072ff;    /* 深靛 */
    --success: #00d084;      /* 薄荷绿 */
    --danger: #ff4757;
    --warning: #ffa502;
    --info: #00d2d3;
    --light: #f1f2f6;
    --dark: #2f3542;
    --shadow: 0 8px 32px rgba(0, 114, 255, .08);
    --radius: 16px;
    --transition: .3s cubic-bezier(.25, .8, .25, 1);
}

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

body {
    font-family: "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    min-height: 100vh;
    color: #333;
    line-height: 1.5;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

.card {
    background: #fff;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 30px;
    margin-bottom: 30px;
    transition: transform var(--transition);
}
.card:hover {
    transform: translateY(-4px);
}
.card-header {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: #fff;
    padding: 20px 30px;
    margin: -30px -30px 30px;
    border-radius: var(--radius) var(--radius) 0 0;
    font-size: 1.25rem;
    font-weight: 600;
}

.form-control {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid #e9ecef;
    border-radius: 8px;
    font-size: 16px;
    transition: border-color var(--transition), box-shadow var(--transition);
}
.form-control:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(0, 198, 255, .2);
}
.form-label {
    font-weight: 600;
    margin-bottom: 8px;
    display: block;
}

.btn {
    display: inline-block;
    padding: 10px 24px;
    font-weight: 600;
    font-size: 15px;
    border: none;
    border-radius: 30px;
    cursor: pointer;
    transition: all var(--transition);
    text-decoration: none;
    text-align: center;
}
.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 7px 20px rgba(0, 0, 0, .12);
}
.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: #fff;
}
.btn-success {
    background: linear-gradient(135deg, var(--success), #00b894);
    color: #fff;
}
.btn-danger {
    background: linear-gradient(135deg, #ff4757, #d63031);
    color: #fff;
}
.btn-warning {
    background: linear-gradient(135deg, var(--warning), #e0a800);
    color: #212529;
}

.table {
    width: 100%;
    border-collapse: collapse;
    background: #fff;
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow);
}
.table th {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: #fff;
    padding: 16px;
    text-align: left;
    font-weight: 600;
}
.table td {
    padding: 14px 16px;
    border-bottom: 1px solid #e9ecef;
}
.table tbody tr:nth-child(even) {
    background: #f8f9fa;
}
.table tbody tr:hover {
    background: #e3f2fd;
}

.navbar {
    background: rgba(255, 255, 255, .95);
    backdrop-filter: blur(10px);
    padding: 15px 0;
    box-shadow: 0 2px 20px rgba(0, 0, 0, .08);
}
.navbar-brand {
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}
.navbar-nav {
    display: flex;
    list-style: none;
    margin-left: auto;
    gap: 15px;
}
.nav-link {
    padding: 8px 16px;
    border-radius: 20px;
    font-weight: 500;
    color: #333;
    transition: all var(--transition);
    text-decoration: none;
}
.nav-link:hover {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: #fff;
}

.balance-display {
    background: linear-gradient(135deg, var(--success), #00b894);
    color: #fff;
    padding: 30px;
    border-radius: var(--radius);
    text-align: center;
    margin-bottom: 30px;
    box-shadow: var(--shadow);
}
.balance-amount {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.alert {
    padding: 15px 20px;
    border-radius: 8px;
    margin-bottom: 20px;
    font-weight: 500;
}
.alert-success {
    background: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}
.alert-danger {
    background: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

@media (max-width: 768px) {
    .container { padding: 10px; }
    .card { padding: 20px; }
    .table { font-size: 14px; }
    .btn { padding: 8px 16px; font-size: 14px; }
}