/* 常州大学外国语学院 毕业论文双选系统 */
:root {
    --primary: #1a56db;
    --primary-light: #e8eefb;
    --primary-dark: #143fa8;
    --success: #0e7a3a;
    --success-bg: #e6f5ec;
    --warning: #b45309;
    --warning-bg: #fef3c7;
    --danger: #c53030;
    --danger-bg: #fee2e2;
    --text: #1a1a2e;
    --text-secondary: #555;
    --border: #d1d5db;
    --bg: #f5f7fa;
    --card: #ffffff;
    --radius: 8px;
}

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

body {
    font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
    color: var(--text);
    background: var(--bg);
    line-height: 1.65;
    font-size: 15px;
}

.container {
    max-width: 880px;
    margin: 0 auto;
    padding: 24px 20px;
}

.container-wide {
    max-width: 1100px;
    margin: 0 auto;
    padding: 24px 20px;
}

/* Header */
.site-header {
    background: var(--primary);
    color: #fff;
    padding: 20px 0;
    margin-bottom: 28px;
}
.site-header .container { display: flex; align-items: center; justify-content: space-between; }
.site-header h1 { font-size: 19px; font-weight: 600; letter-spacing: 0.5px; }
.site-header .subtitle { font-size: 13px; opacity: 0.85; margin-top: 2px; }
.site-header a { color: rgba(255,255,255,0.9); text-decoration: none; font-size: 14px; }
.site-header a:hover { color: #fff; text-decoration: underline; }

/* Cards */
.card {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px;
    margin-bottom: 20px;
}
.card h2 {
    font-size: 18px;
    color: var(--primary);
    margin-bottom: 16px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--primary-light);
}
.card h3 {
    font-size: 15px;
    color: var(--text);
    margin: 18px 0 10px;
}

/* Form elements */
.form-group {
    margin-bottom: 18px;
}
.form-group label {
    display: block;
    font-weight: 600;
    margin-bottom: 6px;
    font-size: 14px;
    color: var(--text);
}
.form-group .hint {
    font-size: 12.5px;
    color: var(--text-secondary);
    margin-top: 3px;
}
input[type="text"],
input[type="email"],
input[type="password"],
input[type="tel"],
select,
textarea {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid var(--border);
    border-radius: 6px;
    font-size: 15px;
    font-family: inherit;
    transition: border-color 0.2s;
}
input:focus, select:focus, textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(26,86,219,0.12);
}
select { background: #fff; }

.checkbox-group {
    display: flex;
    align-items: flex-start;
    gap: 8px;
    padding: 12px;
    background: var(--warning-bg);
    border-radius: 6px;
    margin: 12px 0;
}
.checkbox-group input[type="checkbox"] {
    margin-top: 4px;
    width: 16px;
    height: 16px;
    flex-shrink: 0;
}
.checkbox-group label {
    font-weight: 500;
    font-size: 14px;
    color: var(--warning);
    cursor: pointer;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 10px 22px;
    font-size: 15px;
    font-weight: 600;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    text-decoration: none;
    transition: all 0.2s;
    font-family: inherit;
}
.btn-primary {
    background: var(--primary);
    color: #fff;
}
.btn-primary:hover { background: var(--primary-dark); }
.btn-success { background: var(--success); color: #fff; }
.btn-success:hover { background: #0a5e2d; }
.btn-danger { background: var(--danger); color: #fff; }
.btn-danger:hover { background: #a02424; }
.btn-outline {
    background: transparent;
    color: var(--primary);
    border: 1.5px solid var(--primary);
}
.btn-outline:hover { background: var(--primary-light); }
.btn-sm { padding: 6px 14px; font-size: 13px; }
.btn-block { display: block; width: 100%; text-align: center; }
.btn:disabled { opacity: 0.5; cursor: not-allowed; }

/* Alerts */
.alert {
    padding: 14px 18px;
    border-radius: 6px;
    margin-bottom: 18px;
    font-size: 14px;
    line-height: 1.6;
}
.alert-success { background: var(--success-bg); color: var(--success); border: 1px solid #b2dfc5; }
.alert-warning { background: var(--warning-bg); color: var(--warning); border: 1px solid #fcd581; }
.alert-danger  { background: var(--danger-bg);  color: var(--danger);  border: 1px solid #fca5a5; }
.alert-info    { background: var(--primary-light); color: var(--primary); border: 1px solid #bfcfef; }

/* Tables */
table {
    width: 100%;
    border-collapse: collapse;
    font-size: 14px;
}
th, td {
    padding: 10px 12px;
    text-align: left;
    border-bottom: 1px solid #e5e7eb;
}
th {
    background: var(--bg);
    font-weight: 600;
    font-size: 13px;
    color: var(--text-secondary);
    white-space: nowrap;
}
tr:hover td { background: #f9fafb; }

/* Tags/badges */
.badge {
    display: inline-block;
    padding: 2px 10px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
}
.badge-primary { background: var(--primary-light); color: var(--primary); }
.badge-success { background: var(--success-bg);    color: var(--success); }
.badge-warning { background: var(--warning-bg);    color: var(--warning); }
.badge-danger  { background: var(--danger-bg);     color: var(--danger); }

/* Teacher confirmation: student cards */
.student-card {
    border: 1.5px solid var(--border);
    border-radius: var(--radius);
    padding: 16px;
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 14px;
    transition: border-color 0.2s, background 0.2s;
}
.student-card.selected {
    border-color: var(--primary);
    background: var(--primary-light);
}
.student-card .info { flex: 1; }
.student-card .info .sname { font-weight: 600; font-size: 15px; }
.student-card .info .meta { font-size: 13px; color: var(--text-secondary); margin-top: 2px; }

/* Phase indicator */
.phase-bar {
    display: flex;
    gap: 0;
    margin-bottom: 24px;
    overflow: hidden;
    border-radius: var(--radius);
    border: 1px solid var(--border);
}
.phase-step {
    flex: 1;
    padding: 10px 8px;
    text-align: center;
    font-size: 13px;
    font-weight: 500;
    background: var(--bg);
    color: var(--text-secondary);
    border-right: 1px solid var(--border);
}
.phase-step:last-child { border-right: none; }
.phase-step.active {
    background: var(--primary);
    color: #fff;
}
.phase-step.done {
    background: var(--success-bg);
    color: var(--success);
}

/* Stats grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 14px;
    margin-bottom: 20px;
}
.stat-card {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px;
    text-align: center;
}
.stat-card .number {
    font-size: 28px;
    font-weight: 700;
    color: var(--primary);
}
.stat-card .label {
    font-size: 13px;
    color: var(--text-secondary);
    margin-top: 4px;
}

/* Admin nav */
.admin-nav {
    display: flex;
    gap: 4px;
    margin-bottom: 24px;
    flex-wrap: wrap;
}
.admin-nav a {
    padding: 8px 16px;
    border-radius: 6px;
    font-size: 14px;
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    transition: all 0.2s;
}
.admin-nav a:hover { background: var(--primary-light); color: var(--primary); }
.admin-nav a.active { background: var(--primary); color: #fff; }

/* Footer */
.site-footer {
    text-align: center;
    padding: 24px 0;
    color: #999;
    font-size: 13px;
    margin-top: 32px;
}

/* Responsive */
@media (max-width: 640px) {
    .card { padding: 18px 16px; }
    .container, .container-wide { padding: 16px 12px; }
    .site-header h1 { font-size: 16px; }
    .stats-grid { grid-template-columns: repeat(2, 1fr); }
    table { font-size: 13px; }
    th, td { padding: 8px 6px; }
    .admin-nav { gap: 2px; }
    .admin-nav a { padding: 6px 10px; font-size: 13px; }
}

/* Misc */
.text-center { text-align: center; }
.text-right { text-align: right; }
.mt-2 { margin-top: 8px; }
.mt-4 { margin-top: 16px; }
.mb-2 { margin-bottom: 8px; }
.mb-4 { margin-bottom: 16px; }
.flex { display: flex; }
.flex-between { display: flex; justify-content: space-between; align-items: center; }
.gap-2 { gap: 8px; }
.hidden { display: none; }