:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #dbeafe;
    --bg: #f8fafc;
    --card-bg: #ffffff;
    --text: #1e293b;
    --text-light: #64748b;
    --border: #e2e8f0;
    --danger: #dc2626;
    --danger-dark: #b91c1c;
    --success: #16a34a;
    --warning: #f59e0b;
    --radius: 8px;
    --shadow: 0 1px 3px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.1);
    --max-width: 960px;
}

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

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

a {
    color: var(--primary);
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

/* Header */
.site-header {
    background: var(--card-bg);
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-inner {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 16px;
    height: 56px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    font-size: 20px;
    font-weight: 700;
    color: var(--primary);
    display: flex;
    align-items: center;
    gap: 6px;
}

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

.nav-actions {
    display: flex;
    align-items: center;
    gap: 12px;
}

.nav-actions .welcome {
    font-size: 14px;
    color: var(--text-light);
}

.nav-msg-link {
    position: relative;
}

.nav-badge {
    position: absolute;
    top: -6px;
    right: -6px;
    background: var(--danger);
    color: #fff;
    font-size: 11px;
    min-width: 16px;
    height: 16px;
    line-height: 16px;
    text-align: center;
    border-radius: 8px;
    padding: 0 4px;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 8px 16px;
    border: none;
    border-radius: var(--radius);
    font-size: 14px;
    cursor: pointer;
    transition: all 0.15s;
    font-family: inherit;
    gap: 4px;
}

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

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

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

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

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

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

.btn-sm {
    padding: 4px 10px;
    font-size: 13px;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

/* Main */
main {
    flex: 1;
    max-width: var(--max-width);
    margin: 0 auto;
    width: 100%;
    padding: 24px 16px;
}

/* Hero */
.hero {
    text-align: center;
    padding: 48px 16px 32px;
}

.hero h1 {
    font-size: 32px;
    margin-bottom: 12px;
    color: var(--text);
}

.hero .tagline {
    font-size: 16px;
    color: var(--text-light);
    margin-bottom: 24px;
}

.hero-actions {
    display: flex;
    gap: 12px;
    justify-content: center;
    flex-wrap: wrap;
}

.hero-actions .btn {
    padding: 10px 24px;
    font-size: 15px;
}

.friend-links {
    margin-top: 16px;
    font-size: 14px;
    color: var(--text-light);
}

.friend-links a {
    margin: 0 4px;
}

/* Section */
.section {
    background: var(--card-bg);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 20px;
    margin-bottom: 24px;
}

.section h2 {
    font-size: 18px;
    margin-bottom: 16px;
    padding-bottom: 8px;
    border-bottom: 1px solid var(--border);
}

/* Scroll cards */
.scroll-cards-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 16px;
}

.person-card {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px;
    display: block;
    text-decoration: none;
    color: inherit;
    transition: box-shadow 0.15s;
}

.person-card:hover {
    box-shadow: var(--shadow-md);
    text-decoration: none;
}

.person-card .card-title {
    font-size: 15px;
    font-weight: 600;
    margin-bottom: 6px;
}

.person-card .card-desc {
    font-size: 14px;
    color: var(--text-light);
}

.person-card .card-school {
    font-size: 13px;
    color: var(--primary);
    margin-top: 4px;
}

/* Form */
.form-group {
    margin-bottom: 16px;
}

.form-group label {
    display: block;
    font-size: 14px;
    margin-bottom: 4px;
    font-weight: 500;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 8px 12px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-size: 14px;
    font-family: inherit;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary);
}

.form-group input[readonly] {
    background: var(--bg);
    color: var(--text-light);
}

.form-row {
    display: flex;
    gap: 12px;
}

.form-row .form-group {
    flex: 1;
}

.tag-list {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-bottom: 6px;
}

.tag-item {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    background: var(--primary-light);
    color: var(--primary-dark);
    padding: 4px 10px;
    border-radius: 16px;
    font-size: 13px;
}

.tag-item .tag-remove {
    cursor: pointer;
    font-weight: bold;
    opacity: 0.6;
}

.tag-item .tag-remove:hover {
    opacity: 1;
}

/* Modal */
.modal-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.4);
    z-index: 200;
    align-items: center;
    justify-content: center;
}

.modal-overlay.active {
    display: flex;
}

.modal {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 24px;
    width: 90%;
    max-width: 400px;
    box-shadow: var(--shadow-md);
}

.modal h3 {
    font-size: 18px;
    margin-bottom: 16px;
}

.modal .modal-actions {
    display: flex;
    gap: 8px;
    margin-top: 16px;
}

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

/* Toast */
.toast {
    display: none;
    position: fixed;
    bottom: 24px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--text);
    color: #fff;
    padding: 10px 20px;
    border-radius: var(--radius);
    font-size: 14px;
    z-index: 300;
}

.toast.active {
    display: block;
}

.toast.toast-error {
    background: var(--danger);
}

.toast.toast-success {
    background: var(--success);
}

/* List items */
.list-item {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    padding: 12px 0;
    border-bottom: 1px solid var(--border);
    gap: 12px;
}

.list-item:last-child {
    border-bottom: none;
}

.list-item-info {
    flex: 1;
}

.list-item-info .item-name {
    font-weight: 600;
    font-size: 15px;
}

.list-item-info .item-meta {
    font-size: 13px;
    color: var(--text-light);
    margin-top: 2px;
}

.list-item-info .item-aliases {
    margin-top: 4px;
}

.list-item-actions {
    display: flex;
    gap: 6px;
    flex-shrink: 0;
}

.match-weight {
    display: inline-block;
    background: var(--warning);
    color: #fff;
    padding: 2px 8px;
    border-radius: 12px;
    font-size: 12px;
    font-weight: 600;
}

/* Pagination */
.pagination {
    display: flex;
    justify-content: center;
    gap: 4px;
    margin-top: 16px;
}

.pagination button {
    padding: 6px 12px;
    border: 1px solid var(--border);
    background: var(--card-bg);
    border-radius: var(--radius);
    cursor: pointer;
    font-size: 13px;
}

.pagination button:hover:not(:disabled) {
    border-color: var(--primary);
}

.pagination button.active {
    background: var(--primary);
    color: #fff;
    border-color: var(--primary);
}

.pagination button:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

/* Empty state */
.empty-state {
    text-align: center;
    padding: 32px;
    color: var(--text-light);
    font-size: 14px;
}

.empty-state .empty-icon {
    font-size: 32px;
    margin-bottom: 8px;
}

/* Info grid */
.info-grid {
    display: grid;
    grid-template-columns: 100px 1fr;
    gap: 8px 16px;
    font-size: 14px;
}

.info-grid .info-label {
    color: var(--text-light);
    text-align: right;
}

.info-grid .info-value {
    font-weight: 500;
}

/* Messages */
.message-list {
    max-height: 400px;
    overflow-y: auto;
    padding: 8px 0;
}

.message-item {
    padding: 8px 12px;
    margin: 4px 0;
    border-radius: var(--radius);
    max-width: 75%;
    font-size: 14px;
}

.message-item.sent {
    background: var(--primary);
    color: #fff;
    margin-left: auto;
    text-align: right;
}

.message-item.received {
    background: var(--bg);
    border: 1px solid var(--border);
    margin-right: auto;
}

.message-item .msg-time {
    font-size: 11px;
    opacity: 0.7;
    margin-top: 2px;
}

.conversation-list {
    border-right: 1px solid var(--border);
}

.conversation-item {
    padding: 12px;
    cursor: pointer;
    border-bottom: 1px solid var(--border);
}

.conversation-item:hover {
    background: var(--bg);
}

.conversation-item.active {
    background: var(--primary-light);
}

.conversation-item .conv-name {
    font-weight: 600;
    font-size: 14px;
}

.conversation-item .conv-preview {
    font-size: 12px;
    color: var(--text-light);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.conversation-item .conv-unread {
    display: inline-block;
    background: var(--danger);
    color: #fff;
    font-size: 11px;
    padding: 1px 6px;
    border-radius: 10px;
    margin-left: 4px;
}

.messages-layout {
    display: grid;
    grid-template-columns: 240px 1fr;
    gap: 0;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
    min-height: 500px;
}

.message-send-area {
    display: flex;
    gap: 8px;
    padding: 12px;
    border-top: 1px solid var(--border);
}

.message-send-area input {
    flex: 1;
    padding: 8px 12px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-size: 14px;
}

/* Footer */
footer {
    background: var(--card-bg);
    border-top: 1px solid var(--border);
    padding: 16px;
    text-align: center;
    font-size: 13px;
    color: var(--text-light);
}

footer a {
    margin: 0 6px;
}

footer .icp {
    margin-bottom: 4px;
}

/* Responsive */
@media (max-width: 768px) {
    .header-inner {
        padding: 0 12px;
    }

    .logo {
        font-size: 18px;
    }

    .hero h1 {
        font-size: 24px;
    }

    .hero .tagline {
        font-size: 14px;
    }

    .hero-actions .btn {
        padding: 8px 16px;
        font-size: 14px;
    }

    .scroll-cards-container {
        grid-template-columns: 1fr;
    }

    .form-row {
        flex-direction: column;
        gap: 0;
    }

    .messages-layout {
        grid-template-columns: 1fr;
    }

    .conversation-list {
        display: none;
    }

    .nav-actions .welcome {
        display: none;
    }

    main {
        padding: 16px 12px;
    }

    .section {
        padding: 16px;
    }

    .info-grid {
        grid-template-columns: 80px 1fr;
    }
}