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

:root {
    --text-color: #ffffff;
    --text-shadow: 0 1px 3px rgba(0, 0, 0, 0.3), 0 2px 8px rgba(0, 0, 0, 0.15);
    --text-shadow-strong: 0 1px 2px rgba(0, 0, 0, 0.4), 0 2px 12px rgba(0, 0, 0, 0.2);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    background: linear-gradient(-45deg, #ff6b6b, #feca57, #ff9ff3, #ff6348, #f368e0);
    background-size: 400% 400%;
    animation: gradientBG 15s ease infinite;
    min-height: 100vh;
    overflow-x: hidden;
}

@keyframes gradientBG {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

.welcome-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 9999;
    display: flex;
    justify-content: center;
    align-items: center;
    background: linear-gradient(-45deg, #ff6b6b, #feca57, #ff9ff3, #ff6348, #f368e0);
    background-size: 400% 400%;
    animation: gradientBG 15s ease infinite;
}

.welcome-overlay.hide {
    animation: welcomeFadeOut 0.8s ease-out forwards;
}

@keyframes welcomeFadeOut {
    0% {
        opacity: 1;
        transform: scale(1);
    }
    100% {
        opacity: 0;
        transform: scale(1.1);
        visibility: hidden;
        pointer-events: none;
    }
}

.welcome-content {
    text-align: center;
    z-index: 2;
}

.welcome-title {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-bottom: 40px;
}

.welcome-line {
    display: block;
    opacity: 0;
    transform: translateY(30px);
    color: #ffffff;
    text-shadow: 0 2px 20px rgba(0, 0, 0, 0.3);
}

.line-1 {
    font-size: 64px;
    font-weight: 800;
    letter-spacing: 6px;
    animation: welcomeLineIn 0.8s ease-out forwards;
    animation-delay: 0.3s;
}

.line-2 {
    font-size: 48px;
    font-weight: 600;
    letter-spacing: 8px;
    background: linear-gradient(135deg, #ffffff 0%, #ffeaa7 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: welcomeLineIn 0.8s ease-out forwards;
    animation-delay: 0.6s;
}

.line-3 {
    font-size: 36px;
    font-weight: 500;
    letter-spacing: 4px;
    animation: welcomePulse 1.5s ease-in-out infinite, welcomeLineIn 0.8s ease-out forwards;
    animation-delay: 0.9s, 1.2s;
}

@keyframes welcomeLineIn {
    0% {
        opacity: 0;
        transform: translateY(30px);
    }
    100% {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes welcomePulse {
    0%, 100% {
        opacity: 1;
        transform: scale(1);
    }
    50% {
        opacity: 0.7;
        transform: scale(1.05);
    }
}

.welcome-particles {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
    z-index: 1;
}

.welcome-particles::before,
.welcome-particles::after {
    content: '';
    position: absolute;
    width: 20px;
    height: 20px;
    background: rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    animation: particleFloat 6s ease-in-out infinite;
}

.welcome-particles::before {
    top: 20%;
    left: 20%;
    animation-delay: 0s;
}

.welcome-particles::after {
    top: 60%;
    right: 20%;
    animation-delay: 3s;
}

@keyframes particleFloat {
    0%, 100% {
        transform: translateY(0) rotate(0deg);
        opacity: 0.3;
    }
    50% {
        transform: translateY(-30px) rotate(180deg);
        opacity: 0.6;
    }
}

.back-button {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 1000;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: rgba(255, 255, 255, 0.18);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid rgba(255, 255, 255, 0.3);
    color: var(--text-color);
    text-decoration: none;
    padding: 10px 20px;
    border-radius: 30px;
    font-size: 15px;
    font-weight: 600;
    text-shadow: var(--text-shadow);
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.12);
    transition: all 0.3s ease;
}

.back-button:hover {
    background: rgba(255, 255, 255, 0.32);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.2);
}

.back-button:active {
    transform: translateY(0);
}

.back-icon {
    font-size: 18px;
    font-weight: 700;
    transition: transform 0.3s ease;
}

.back-button:hover .back-icon {
    transform: translateX(-3px);
}

.container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

.notice-bar {
    background: linear-gradient(90deg, #fa709a 0%, #fee140 100%);
    border-radius: 12px;
    padding: 16px 20px;
    box-shadow: 0 4px 20px rgba(250, 112, 154, 0.3);
    margin-bottom: 40px;
    overflow: hidden;
}

.notice-content {
    display: flex;
    align-items: center;
    gap: 12px;
}

.notice-icon {
    font-size: 24px;
    flex-shrink: 0;
    animation: bounce 1.5s infinite;
}

@keyframes bounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-5px); }
}

.notice-scroll {
    display: flex;
    animation: scroll-left 30s linear infinite;
    white-space: nowrap;
}

@keyframes scroll-left {
    0% { transform: translateX(0); }
    100% { transform: translateX(-50%); }
}

.notice-text {
    font-size: 18px;
    font-weight: 600;
    color: #1a1a1a;
    text-shadow: 0 1px 2px rgba(255, 255, 255, 0.6);
    padding-right: 60px;
}

.logo-section {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 80px 20px;
}

.logo-wrapper {
    text-align: center;
    animation: fadeInUp 1s ease-out;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.logo-text {
    font-size: 72px;
    font-weight: 800;
    color: var(--text-color);
    text-shadow: 0 4px 30px rgba(0, 0, 0, 0.25);
    margin-bottom: 20px;
    letter-spacing: 4px;
    transition: color 0.4s ease, text-shadow 0.4s ease;
}

.version-badge {
    display: inline-block;
    background: rgba(255, 255, 255, 0.2);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.3);
    color: var(--text-color);
    text-shadow: var(--text-shadow);
    padding: 8px 24px;
    border-radius: 30px;
    font-size: 18px;
    font-weight: 500;
    transition: color 0.4s ease;
}

.content-section {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    padding: 40px 0;
}

.feature-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 24px;
    width: 100%;
}

.feature-card {
    background: rgba(255, 255, 255, 0.15);
    backdrop-filter: blur(15px);
    -webkit-backdrop-filter: blur(15px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 16px;
    padding: 30px;
    text-align: center;
    transition: all 0.3s ease;
    animation: fadeInUp 1s ease-out;
}

.feature-card:hover {
    transform: translateY(-10px);
    background: rgba(255, 255, 255, 0.25);
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
}

.feature-icon {
    font-size: 48px;
    margin-bottom: 16px;
}

.feature-card h3 {
    color: var(--text-color);
    font-size: 22px;
    margin-bottom: 8px;
    font-weight: 600;
    text-shadow: var(--text-shadow);
    transition: color 0.4s ease;
}

.feature-card p {
    color: var(--text-color);
    opacity: 0.82;
    font-size: 14px;
    text-shadow: var(--text-shadow);
    transition: color 0.4s ease;
}

@media (max-width: 768px) {
    .logo-text {
        font-size: 48px;
    }

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

    .notice-text {
        font-size: 15px;
    }

    .back-button {
        top: 12px;
        right: 12px;
        padding: 8px 14px;
        font-size: 13px;
    }
}

.app-introduction,
.project-introduction {
    margin-top: 40px;
    animation: fadeInUp 1s ease-out;
}

.section-title {
    font-size: 32px;
    color: var(--text-color);
    font-weight: 700;
    margin-bottom: 24px;
    padding-left: 16px;
    border-left: 4px solid var(--text-color);
    text-shadow: var(--text-shadow);
    transition: color 0.4s ease, border-color 0.4s ease;
}

.intro-card {
    background: rgba(255, 255, 255, 0.12);
    backdrop-filter: blur(15px);
    -webkit-backdrop-filter: blur(15px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 20px;
    padding: 36px;
}

.intro-text {
    color: var(--text-color);
    opacity: 0.9;
    font-size: 16px;
    line-height: 1.8;
    margin-bottom: 24px;
    text-shadow: var(--text-shadow);
    transition: color 0.4s ease;
}

.intro-features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 16px;
}

.intro-item {
    display: flex;
    align-items: center;
    gap: 10px;
    background: rgba(255, 255, 255, 0.1);
    padding: 14px 18px;
    border-radius: 12px;
    color: var(--text-color);
    font-size: 15px;
    text-shadow: var(--text-shadow);
    transition: all 0.3s ease, color 0.4s ease;
}

.intro-item:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: translateY(-2px);
}

.intro-icon {
    font-size: 22px;
}

.tech-stack {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 16px;
}

.tech-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
    padding: 20px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 16px;
    transition: all 0.3s ease;
}

.tech-item:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: translateY(-2px);
}

.tech-badge {
    background: linear-gradient(135deg, #fa709a 0%, #fee140 100%);
    color: #ffffff;
    padding: 8px 16px;
    border-radius: 20px;
    font-weight: 700;
    font-size: 15px;
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.2);
}

.tech-item span:last-child {
    color: var(--text-color);
    opacity: 0.82;
    font-size: 14px;
    text-shadow: var(--text-shadow);
    transition: color 0.4s ease;
}

.screenshot-section {
    margin-top: 40px;
    animation: fadeInUp 1s ease-out;
}

.screenshot-card {
    background: rgba(255, 255, 255, 0.12);
    backdrop-filter: blur(15px);
    -webkit-backdrop-filter: blur(15px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 20px;
    padding: 24px;
    overflow: hidden;
}

.screenshot-image {
    display: block;
    width: 100%;
    max-width: 800px;
    margin: 0 auto;
    border-radius: 12px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.15);
    transition: transform 0.4s ease, box-shadow 0.4s ease;
}

.screenshot-image:hover {
    transform: scale(1.02);
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.25);
}