:root {
    --primary-color: #007aff;
    --primary-hover: #0062cc;
    --bg-color: #f2f2f7;
    --card-bg: #ffffff;
    --text-primary: #1c1c1e;
    --text-secondary: #8e8e93;
    --border-color: #e5e5ea;
    --success-color: #34c759;
    --card-radius: 18px;
    --btn-radius: 980px; /* Capsule shape */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 16px 40px rgba(0, 0, 0, 0.12);
    --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.5;
    padding-bottom: 40px;
    min-height: 100vh;
}

/* 顶部装饰背景 */
body::before {
    content: '';
    position: fixed;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle at center, rgba(255,255,255,0.8) 0%, rgba(242,242,247,0) 70%);
    pointer-events: none;
    z-index: -1;
}

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

/* Header 区域 */
header {
    text-align: center;
    padding: 60px 0 40px;
    animation: fadeInDown 0.8s ease-out;
}

header h1 {
    font-size: 3.5rem;
    font-weight: 800;
    letter-spacing: -0.02em;
    background: linear-gradient(135deg, #1c1c1e 0%, #3a3a3c 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 12px;
}

header p {
    color: var(--text-secondary);
    font-size: 1.1rem;
    font-weight: 400;
}

/* 搜索框区域 */
.search-box {
    max-width: 720px;
    margin: 0 auto 50px;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    padding: 10px;
    border-radius: 20px;
    box-shadow: var(--shadow-md);
    border: 1px solid rgba(255, 255, 255, 0.5);
    transform: translateY(0);
    transition: var(--transition);
    animation: fadeInUp 0.8s ease-out 0.2s backwards;
}

.search-box:focus-within {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
    background: rgba(255, 255, 255, 0.95);
}

.input-group {
    display: flex;
    gap: 12px;
    align-items: center;
}

select {
    padding: 14px 20px;
    border: none;
    border-radius: 14px;
    font-size: 15px;
    font-weight: 500;
    background-color: #f2f2f7;
    color: var(--text-primary);
    cursor: pointer;
    outline: none;
    transition: var(--transition);
    appearance: none;
    background-image: url("data:image/svg+xml;charset=UTF-8,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%238e8e93' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3e%3cpolyline points='6 9 12 15 18 9'%3e%3c/polyline%3e%3c/svg%3e");
    background-repeat: no-repeat;
    background-position: right 12px center;
    background-size: 16px;
    padding-right: 40px;
}

select:hover {
    background-color: #e5e5ea;
}

input[type="text"] {
    flex: 1;
    padding: 14px 20px;
    border: none;
    background: transparent;
    font-size: 17px;
    color: var(--text-primary);
    outline: none;
}

input[type="text"]::placeholder {
    color: #aeaeb2;
}

button#search-btn {
    padding: 14px 32px;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 14px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: 0 4px 12px rgba(0, 122, 255, 0.3);
}

button#search-btn:hover {
    background-color: var(--primary-hover);
    transform: scale(1.02);
}

button#search-btn:active {
    transform: scale(0.98);
}

/* 结果网格 */
.results-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 24px;
    padding-bottom: 40px;
}

/* App 卡片 */
.app-card {
    background: var(--card-bg);
    border-radius: var(--card-radius);
    padding: 24px;
    box-shadow: var(--shadow-sm);
    display: flex;
    flex-direction: column;
    gap: 20px;
    transition: var(--transition);
    border: 1px solid rgba(0, 0, 0, 0.02);
    position: relative;
    overflow: hidden;
    animation: fadeIn 0.5s ease-out;
}

.app-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
}

.app-header {
    display: flex;
    gap: 18px;
    align-items: flex-start;
}

.app-icon {
    width: 88px;
    height: 88px;
    border-radius: 20px;
    border: 1px solid rgba(0, 0, 0, 0.05);
    object-fit: cover;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.06);
    transition: transform 0.3s ease;
}

.app-card:hover .app-icon {
    transform: scale(1.05);
}

.app-info {
    flex: 1;
    min-width: 0;
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.app-name {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-primary);
    line-height: 1.3;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.app-developer {
    font-size: 0.9rem;
    color: var(--text-secondary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.app-price-tag {
    display: inline-flex;
    align-self: flex-start;
    padding: 4px 10px;
    background-color: #f2f2f7;
    border-radius: 100px;
    font-size: 0.75rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-top: 4px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.app-price-tag.paid {
    color: #ff3b30;
    background-color: rgba(255, 59, 48, 0.1);
}

.app-details {
    background: #f9f9fa;
    padding: 16px;
    border-radius: 14px;
    font-size: 0.85rem;
    color: var(--text-secondary);
    display: grid;
    grid-template-columns: auto 1fr;
    gap: 8px 16px;
    border: 1px solid rgba(0, 0, 0, 0.03);
}

.label {
    font-weight: 600;
    color: #48484a;
}

.value {
    word-break: break-all;
    font-variant-numeric: tabular-nums;
}

.download-btn {
    width: 100%;
    padding: 14px;
    background-color: var(--bg-color);
    color: var(--primary-color);
    border: none;
    border-radius: 14px;
    font-weight: 600;
    font-size: 15px;
    cursor: pointer;
    margin-top: auto;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    transition: var(--transition);
}

.download-btn:hover {
    background-color: #e5e5ea;
    color: var(--primary-hover);
}

.download-btn:active {
    transform: scale(0.98);
}

.download-btn svg {
    transition: transform 0.3s ease;
}

.download-btn:hover svg {
    transform: translateY(2px);
}

.download-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

/* Loading & Error */
.hidden {
    display: none !important;
}

#loading {
    text-align: center;
    padding: 60px;
    color: var(--text-secondary);
}

.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid #e5e5ea;
    border-top: 3px solid var(--primary-color);
    border-radius: 50%;
    margin: 0 auto 16px;
    animation: spin 0.8s cubic-bezier(0.68, -0.55, 0.265, 1.55) infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeInDown {
    from { opacity: 0; transform: translateY(-20px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

#error-msg {
    text-align: center;
    color: #ff3b30;
    padding: 24px;
    background: rgba(255, 59, 48, 0.1);
    border-radius: 16px;
    margin-bottom: 30px;
    font-weight: 500;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

/* 响应式适配 */
@media (max-width: 600px) {
    header h1 {
        font-size: 2.5rem;
    }
    
    .input-group {
        flex-direction: column;
        gap: 10px;
    }
    
    select {
        width: 100%;
        padding-right: 20px;
        background-position: right 16px center;
    }
    
    input[type="text"] {
        width: 100%;
        text-align: center;
        border-top: 1px solid var(--border-color);
        border-bottom: 1px solid var(--border-color);
        border-radius: 0;
        padding: 16px;
    }

    button#search-btn {
        width: 100%;
    }
    
    .search-box {
        padding: 16px;
        border-radius: 24px;
    }
}