:root {
    --color-bg: #f5f7fa;
    --color-surface: #ffffff;
    --color-border: #e4e7eb;
    --color-text: #1f2937;
    --color-text-muted: #6b7280;
    --color-primary: #16a085;
    --color-primary-soft: #e6f4f1;
    --color-focus: #16a085;
    --radius: 12px;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
    --shadow-hover: 0 4px 12px rgba(22, 160, 133, 0.12);
}

* {
    box-sizing: border-box;
}

html, body {
    margin: 0;
    padding: 0;
    background: var(--color-bg);
    color: var(--color-text);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang TC", "Microsoft JhengHei", Roboto, sans-serif;
    -webkit-font-smoothing: antialiased;
}

.page {
    max-width: 780px;
    margin: 0 auto;
    padding: 32px 20px 60px;
}

.page-header h1 {
    margin: 0 0 4px;
    font-size: 28px;
    font-weight: 700;
    letter-spacing: -0.02em;
}

.subtitle {
    margin: 0 0 24px;
    color: var(--color-text-muted);
    font-size: 14px;
}

.toolbar {
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-bottom: 24px;
}

.search-wrap {
    position: relative;
    display: flex;
    align-items: center;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 0 12px;
    transition: border-color 0.15s, box-shadow 0.15s;
}

.search-wrap:focus-within {
    border-color: var(--color-focus);
    box-shadow: 0 0 0 3px rgba(22, 160, 133, 0.15);
}

.search-icon {
    color: var(--color-text-muted);
    font-size: 14px;
    padding-right: 8px;
    line-height: 1;
}

.search-input {
    flex: 1;
    height: 44px;
    border: none;
    outline: none;
    background: transparent;
    font-size: 15px;
    color: var(--color-text);
    font-family: inherit;
}

.search-clear {
    background: none;
    border: none;
    color: var(--color-text-muted);
    font-size: 22px;
    cursor: pointer;
    padding: 0 4px;
    line-height: 1;
}

.search-clear:hover {
    color: var(--color-text);
}

.chip-row {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
}

.chip {
    padding: 6px 12px;
    border: 1px solid var(--color-border);
    border-radius: 16px;
    background: var(--color-surface);
    color: var(--color-text-muted);
    font-size: 13px;
    cursor: pointer;
    font-family: inherit;
    transition: background 0.15s, color 0.15s, border-color 0.15s;
}

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

.chip.active {
    background: var(--color-primary);
    color: white;
    border-color: var(--color-primary);
}

.app-list {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.app-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    transition: transform 0.1s, box-shadow 0.15s, border-color 0.15s;
}

.app-card:hover {
    border-color: var(--color-primary);
    box-shadow: var(--shadow-hover);
    transform: translateY(-1px);
}

.app-link {
    display: flex;
    gap: 16px;
    align-items: center;
    padding: 16px 18px;
    text-decoration: none;
    color: inherit;
}

.app-icon {
    flex-shrink: 0;
    font-size: 36px;
    line-height: 1;
    width: 52px;
    height: 52px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--color-primary-soft);
    border-radius: 10px;
}

.app-body {
    flex: 1;
    min-width: 0;
}

.app-title-row {
    display: flex;
    align-items: baseline;
    gap: 8px;
    margin-bottom: 4px;
}

.app-title {
    margin: 0;
    font-size: 17px;
    font-weight: 600;
    color: var(--color-text);
}

.app-subject {
    font-size: 12px;
    color: var(--color-primary);
    background: var(--color-primary-soft);
    padding: 2px 8px;
    border-radius: 8px;
    font-weight: 600;
}

.app-desc {
    margin: 0 0 6px;
    font-size: 13px;
    color: var(--color-text-muted);
    line-height: 1.5;
}

.app-levels {
    display: flex;
    flex-wrap: wrap;
    gap: 4px;
}

.level-tag {
    font-size: 11px;
    padding: 2px 8px;
    background: #f3f4f6;
    color: #4b5563;
    border-radius: 8px;
}

.app-arrow {
    flex-shrink: 0;
    color: var(--color-text-muted);
    font-size: 20px;
    transition: transform 0.15s, color 0.15s;
}

.app-card:hover .app-arrow {
    color: var(--color-primary);
    transform: translateX(3px);
}

.state {
    text-align: center;
    color: var(--color-text-muted);
    padding: 40px 20px;
}

.state-icon {
    font-size: 40px;
    margin-bottom: 12px;
}

.btn-plain {
    margin-top: 12px;
    padding: 6px 14px;
    border: 1px solid var(--color-border);
    background: white;
    border-radius: 6px;
    color: var(--color-text-muted);
    cursor: pointer;
    font-family: inherit;
    font-size: 13px;
}

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

.page-footer {
    margin-top: 32px;
    text-align: center;
    color: var(--color-text-muted);
    font-size: 12px;
}

@media (max-width: 500px) {
    .page {
        padding: 20px 14px 40px;
    }
    .page-header h1 {
        font-size: 22px;
    }
    .app-icon {
        width: 44px;
        height: 44px;
        font-size: 28px;
    }
    .app-title {
        font-size: 15px;
    }
}