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

:root {
    --bg-color: #ffffff;
    --text-color: #0a0a0a;
    --text-secondary: #64748b;
    --text-tertiary: #475569;
    --border-color: #e2e8f0;
    --footer-border: #e2e8f0;
    --footer-text: #94a3b8;
    --footer-link: #94a3b8;
    --footer-link-hover: #02608a;
    --developer-text: #cbd5e1;
}

[data-theme="dark"] {
    --bg-color: #0a0a0a;
    --text-color: #f8fafc;
    --text-secondary: #94a3b8;
    --text-tertiary: #cbd5e1;
    --border-color: #1e293b;
    --footer-border: #1e293b;
    --footer-text: #64748b;
    --footer-link: #64748b;
    --footer-link-hover: #29cff5;
    --developer-text: #475569;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Helvetica Neue', Arial, sans-serif;
    background: var(--bg-color);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 40px 20px;
    color: var(--text-color);
    line-height: 1.6;
    position: relative;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
    max-width: 900px;
    width: 100%;
    background: transparent;
    padding: 80px 60px;
    position: relative;
    z-index: 1;
    margin: 0 auto;
}

.top-controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 100px;
    gap: 20px;
}

.language-selector {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

.theme-toggle {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 8px 16px;
    border: 1.5px solid var(--border-color);
    background: transparent;
    cursor: pointer;
    border-radius: 24px;
    transition: all 0.3s ease;
    flex-shrink: 0;
    position: relative;
}

.theme-toggle:hover {
    border-color: var(--text-secondary);
    background: rgba(0, 0, 0, 0.02);
}

[data-theme="dark"] .theme-toggle:hover {
    border-color: var(--text-secondary);
    background: rgba(255, 255, 255, 0.05);
}

.theme-icon {
    font-size: 18px;
    line-height: 1;
    transition: opacity 0.3s ease, transform 0.3s ease;
    display: flex;
    align-items: center;
}

.sun-icon {
    opacity: 1;
    transform: scale(1);
}

.moon-icon {
    opacity: 0.3;
    transform: scale(0.8);
}

[data-theme="dark"] .sun-icon {
    opacity: 0.3;
    transform: scale(0.8);
}

[data-theme="dark"] .moon-icon {
    opacity: 1;
    transform: scale(1);
}

.toggle-slider {
    width: 44px;
    height: 24px;
    background: #cbd5e1;
    border-radius: 12px;
    position: relative;
    transition: all 0.3s ease;
}

.toggle-slider::before {
    content: '';
    position: absolute;
    width: 18px;
    height: 18px;
    background: #ffffff;
    border-radius: 50%;
    top: 3px;
    left: 3px;
    transition: all 0.3s ease;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

[data-theme="dark"] .toggle-slider {
    background: #475569;
}

[data-theme="dark"] .toggle-slider::before {
    left: 23px;
    background: #f8fafc;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.4);
}

.toggle-label {
    font-size: 12px;
    font-weight: 500;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 1px;
    min-width: 30px;
    transition: color 0.3s ease;
}

[data-theme="dark"] .toggle-label {
    color: var(--text-secondary);
}

.lang-btn {
    padding: 10px 20px;
    border: none;
    background: transparent;
    color: var(--text-secondary);
    cursor: pointer;
    font-weight: 400;
    transition: all 0.2s ease;
    font-size: 14px;
    font-family: inherit;
    text-transform: uppercase;
    letter-spacing: 1px;
    display: flex;
    align-items: center;
    gap: 10px;
    position: relative;
}

.lang-btn::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--text-color);
    transition: width 0.3s ease;
}

.lang-btn .flag {
    width: 20px;
    height: 15px;
    object-fit: cover;
    border-radius: 2px;
    display: block;
    flex-shrink: 0;
    border: 0.5px solid rgba(0, 0, 0, 0.1);
}

.lang-btn .lang-code {
    font-size: 14px;
}

.lang-btn:hover {
    color: var(--text-color);
}

.lang-btn:hover::after {
    width: 100%;
}

.lang-btn.active {
    color: var(--text-color);
}

.lang-btn.active::after {
    width: 100%;
}

.content {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    gap: 80px;
}

.logo-container {
    width: 300px;
    height: 180px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
}

.logo-wrapper {
    position: relative;
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    user-select: none;
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    pointer-events: none;
}

.logo {
    width: 100%;
    height: auto;
    max-width: 100%;
    object-fit: contain;
    user-select: none;
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    -webkit-user-drag: none;
    -khtml-user-drag: none;
    -moz-user-drag: none;
    -o-user-drag: none;
    user-drag: none;
    pointer-events: none;
    filter: brightness(1);
    transition: filter 0.3s ease;
}

[data-theme="dark"] .logo {
    filter: brightness(1.1);
}

.text-content {
    width: 100%;
    max-width: 700px;
    margin: 0 auto;
}

.acronym {
    font-size: 64px;
    font-weight: 300;
    color: var(--text-color);
    margin-bottom: 60px;
    letter-spacing: 20px;
    font-family: inherit;
    text-transform: uppercase;
    line-height: 1;
    transition: color 0.3s ease;
    word-spacing: 0;
}

.title {
    margin-bottom: 50px;
}

.title h2 {
    font-size: 28px;
    color: var(--text-color);
    margin-bottom: 12px;
    line-height: 1.4;
    font-weight: 300;
    font-family: inherit;
    letter-spacing: -0.3px;
    transition: color 0.3s ease;
}

.title h3 {
    font-size: 18px;
    color: var(--text-secondary);
    margin-bottom: 0;
    font-weight: 300;
    font-family: inherit;
    letter-spacing: 0.5px;
    transition: color 0.3s ease;
}

.title.zh h2,
.title.zh h3 {
    font-family: 'Microsoft YaHei', 'SimHei', 'PingFang SC', 'Noto Sans SC', sans-serif;
}

.coming-soon {
    margin: 70px 0;
    padding: 0;
    position: relative;
}

.coming-soon-text {
    font-size: 11px;
    font-weight: 400;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 8px;
    font-family: inherit;
    position: relative;
    transition: color 0.3s ease;
}

.description {
    margin-top: 60px;
}

.desc-text {
    font-size: 16px;
    color: var(--text-tertiary);
    line-height: 1.9;
    max-width: 550px;
    margin: 0 auto;
    font-weight: 300;
    font-family: inherit;
    letter-spacing: 0.2px;
    transition: color 0.3s ease;
}

.desc-text.zh {
    font-family: 'Microsoft YaHei', 'SimHei', 'PingFang SC', 'Noto Sans SC', sans-serif;
}

.footer {
    margin-top: 120px;
    padding-top: 40px;
    border-top: 1px solid var(--footer-border);
    text-align: center;
    transition: border-color 0.3s ease;
}

.footer-text p {
    font-size: 12px;
    color: var(--footer-text);
    font-weight: 300;
    font-family: inherit;
    letter-spacing: 0.3px;
    margin-bottom: 8px;
    line-height: 1.6;
    transition: color 0.3s ease;
}

.footer-text p:last-child {
    margin-bottom: 0;
}

.footer-text .developer {
    margin-top: 12px;
    font-size: 11px;
    color: var(--developer-text);
    transition: color 0.3s ease;
}

.footer-text .developer a {
    color: var(--footer-link);
    text-decoration: none;
    transition: color 0.2s ease;
}

.footer-text .developer a:hover {
    color: var(--footer-link-hover);
}

.footer-text .attribution {
    margin-top: 8px;
    font-size: 9px;
    color: var(--developer-text);
    opacity: 0.6;
    transition: color 0.3s ease;
}

.footer-text.zh p {
    font-family: 'Microsoft YaHei', 'SimHei', 'PingFang SC', 'Noto Sans SC', sans-serif;
}

/* Responsive Design */
@media (max-width: 768px) {
    body {
        padding: 30px 15px;
    }

    .container {
        padding: 60px 40px;
    }

    .top-controls {
        margin-bottom: 70px;
        flex-direction: column;
        align-items: center;
        gap: 20px;
    }

    .language-selector {
        width: 100%;
        justify-content: center;
    }

    .theme-toggle {
        padding: 6px 12px;
        gap: 8px;
    }

    .theme-icon {
        font-size: 16px;
    }

    .toggle-slider {
        width: 40px;
        height: 22px;
    }

    .toggle-slider::before {
        width: 16px;
        height: 16px;
        top: 3px;
        left: 3px;
    }

    [data-theme="dark"] .toggle-slider::before {
        left: 21px;
    }

    .toggle-label {
        font-size: 11px;
        min-width: 25px;
    }

    .logo-container {
        width: 240px;
        height: 144px;
    }

    .content {
        gap: 60px;
    }

    .acronym {
        font-size: 48px;
        letter-spacing: 16px;
        margin-bottom: 50px;
    }

    .title {
        margin-bottom: 40px;
    }

    .title h2 {
        font-size: 24px;
    }

    .title h3 {
        font-size: 16px;
    }

    .coming-soon {
        margin: 60px 0;
    }

    .coming-soon-text {
        font-size: 10px;
        letter-spacing: 6px;
    }

    .description {
        margin-top: 50px;
    }

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

    .footer {
        margin-top: 100px;
        padding-top: 35px;
    }
}

@media (max-width: 480px) {
    body {
        padding: 20px 10px;
    }

    .container {
        padding: 40px 25px;
    }

    .top-controls {
        margin-bottom: 60px;
        flex-direction: column;
        align-items: center;
        gap: 20px;
    }

    .language-selector {
        gap: 8px;
        justify-content: center;
        flex-wrap: wrap;
    }

    .lang-btn {
        padding: 8px 16px;
        font-size: 12px;
    }

    .lang-btn .flag {
        font-size: 18px;
    }

    .theme-toggle {
        padding: 5px 10px;
        gap: 6px;
    }

    .theme-icon {
        font-size: 14px;
    }

    .toggle-slider {
        width: 36px;
        height: 20px;
    }

    .toggle-slider::before {
        width: 14px;
        height: 14px;
        top: 3px;
        left: 3px;
    }

    [data-theme="dark"] .toggle-slider::before {
        left: 19px;
    }

    .toggle-label {
        font-size: 10px;
        min-width: 20px;
    }

    .logo-container {
        width: 200px;
        height: 120px;
    }

    .content {
        gap: 50px;
    }

    .acronym {
        font-size: 36px;
        letter-spacing: 12px;
        margin-bottom: 40px;
    }

    .title {
        margin-bottom: 35px;
    }

    .title h2 {
        font-size: 20px;
    }

    .title h3 {
        font-size: 15px;
    }

    .coming-soon {
        margin: 50px 0;
    }

    .coming-soon-text {
        font-size: 9px;
        letter-spacing: 5px;
    }

    .description {
        margin-top: 45px;
    }

    .desc-text {
        font-size: 14px;
        line-height: 1.8;
    }

    .footer {
        margin-top: 90px;
        padding-top: 30px;
    }
}

@media (max-width: 360px) {
    .container {
        padding: 30px 20px;
    }

    .acronym {
        font-size: 32px;
        letter-spacing: 10px;
    }

    .lang-btn {
        padding: 6px 12px;
        font-size: 11px;
    }

    .lang-btn .flag {
        font-size: 16px;
    }
}