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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    position: relative;
}

/* 动态背景 */
.animated-bg {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 50%, #f093fb 100%);
    background-size: 400% 400%;
    animation: gradientShift 8s ease infinite;
}

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

/* 浮动几何图形 */
.floating-shapes {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    pointer-events: none;
}

.shape {
    position: absolute;
    opacity: 0.1;
    animation: float 6s ease-in-out infinite;
}

.shape:nth-child(1) {
    top: 20%;
    left: 10%;
    width: 80px;
    height: 80px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 50%;
    animation-delay: 0s;
    animation-duration: 8s;
}

.shape:nth-child(2) {
    top: 60%;
    left: 80%;
    width: 60px;
    height: 60px;
    background: rgba(255, 255, 255, 0.15);
    border-radius: 10px;
    animation-delay: 2s;
    animation-duration: 10s;
}

.shape:nth-child(3) {
    top: 80%;
    left: 20%;
    width: 100px;
    height: 100px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    animation-delay: 4s;
    animation-duration: 12s;
}

.shape:nth-child(4) {
    top: 10%;
    left: 70%;
    width: 40px;
    height: 40px;
    background: rgba(255, 255, 255, 0.2);
    transform: rotate(45deg);
    animation-delay: 1s;
    animation-duration: 9s;
}

.shape:nth-child(5) {
    top: 40%;
    left: 5%;
    width: 70px;
    height: 70px;
    background: rgba(255, 255, 255, 0.12);
    border-radius: 20px;
    animation-delay: 3s;
    animation-duration: 11s;
}

.shape:nth-child(6) {
    top: 70%;
    left: 60%;
    width: 50px;
    height: 50px;
    background: rgba(255, 255, 255, 0.18);
    border-radius: 50%;
    animation-delay: 5s;
    animation-duration: 7s;
}

@keyframes float {
    0%, 100% {
        transform: translateY(0px) rotate(0deg);
        opacity: 0.1;
    }
    50% {
        transform: translateY(-20px) rotate(180deg);
        opacity: 0.3;
    }
}

.login-container {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(15px);
    border-radius: 25px;
    padding: 50px 40px;
    box-shadow:
        0 25px 50px rgba(0, 0, 0, 0.15),
        0 0 0 1px rgba(255, 255, 255, 0.2);
    text-align: center;
    max-width: 420px;
    width: 90%;
    position: relative;
    animation: containerFadeIn 1s ease-out;
    transform-style: preserve-3d;
}

.login-container::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.1) 0%, rgba(255, 255, 255, 0.05) 100%);
    border-radius: 25px;
    z-index: -1;
}

@keyframes containerFadeIn {
    0% {
        opacity: 0;
        transform: translateY(30px) scale(0.9);
    }
    100% {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

.logo {
    font-size: 3em;
    margin-bottom: 15px;
    color: #667eea;
    animation: logoFloat 3s ease-in-out infinite, logoFadeIn 1s ease-out;
    text-shadow: 0 0 20px rgba(102, 126, 234, 0.3);
}

@keyframes logoFloat {
    0%, 100% {
        transform: translateY(0px) rotate(0deg);
    }
    50% {
        transform: translateY(-10px) rotate(5deg);
    }
}

@keyframes logoFadeIn {
    0% {
        opacity: 0;
        transform: scale(0.5) rotate(-180deg);
    }
    100% {
        opacity: 1;
        transform: scale(1) rotate(0deg);
    }
}

h1 {
    color: #333;
    margin-bottom: 35px;
    font-weight: 300;
    font-size: 1.8em;
    animation: titleSlideUp 0.8s ease-out 0.2s both;
    background: linear-gradient(135deg, #333 0%, #667eea 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

@keyframes titleSlideUp {
    0% {
        opacity: 0;
        transform: translateY(20px);
    }
    100% {
        opacity: 1;
        transform: translateY(0);
    }
}

.login-buttons {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.login-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 16px 24px;
    border: none;
    border-radius: 15px;
    font-size: 16px;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    cursor: pointer;
    position: relative;
    overflow: hidden;
    animation: buttonSlideIn 0.6s ease-out forwards;
    opacity: 0;
    transform: translateX(-30px);
}

.login-btn:nth-child(1) {
    animation-delay: 0.3s;
}

.login-btn:nth-child(2) {
    animation-delay: 0.5s;
}

.login-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: left 0.5s;
}

.login-btn:hover::before {
    left: 100%;
}

@keyframes buttonSlideIn {
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.github-btn {
    background: linear-gradient(135deg, #24292e 0%, #1a1e22 100%);
    color: white;
    box-shadow: 0 8px 25px rgba(36, 41, 46, 0.3);
}

.github-btn:hover {
    background: linear-gradient(135deg, #1a1e22 0%, #0d1117 100%);
    transform: translateY(-3px) scale(1.02);
    box-shadow: 0 15px 35px rgba(36, 41, 46, 0.4);
}

.gitee-btn {
    background: linear-gradient(135deg, #c71d23 0%, #a01419 100%);
    color: white;
    box-shadow: 0 8px 25px rgba(199, 29, 35, 0.3);
}

.gitee-btn:hover {
    background: linear-gradient(135deg, #a01419 0%, #8b1116 100%);
    transform: translateY(-3px) scale(1.02);
    box-shadow: 0 15px 35px rgba(199, 29, 35, 0.4);
}

.btn-icon {
    margin-right: 12px;
    width: 20px;
    height: 20px;
    fill: currentColor;
    flex-shrink: 0;
}

.btn-icon-text {
    margin-right: 12px;
    width: 20px;
    height: 20px;
    background: currentColor;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 12px;
    font-weight: bold;
    color: #c53030;
    flex-shrink: 0;
}