/* ==================== 全局样式 ==================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html, body {
    width: 100%;
    height: 100%;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    overflow: hidden;
}

/* ==================== 动态背景 ==================== */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 50%, #f093fb 100%);
    background-size: 400% 400%;
    animation: gradientShift 15s ease infinite;
    z-index: -2;
}

body::after {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background:
        radial-gradient(circle at 20% 50%, rgba(255, 107, 107, 0.3) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(102, 126, 234, 0.3) 0%, transparent 50%),
        radial-gradient(circle at 40% 20%, rgba(240, 147, 251, 0.2) 0%, transparent 50%);
    animation: floatShift 20s ease-in-out infinite;
    z-index: -1;
}

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

@keyframes floatShift {
    0%, 100% {
        transform: translate(0, 0);
    }
    25% {
        transform: translate(30px, -30px);
    }
    50% {
        transform: translate(-20px, 20px);
    }
    75% {
        transform: translate(20px, 30px);
    }
}

/* ==================== 浮动粒子 ==================== */
.particle {
    position: fixed;
    pointer-events: none;
    z-index: -1;
}

.particle::before {
    content: '';
    position: absolute;
    width: 100%;
    height: 100%;
    background: radial-gradient(circle, rgba(255, 255, 255, 0.8) 0%, transparent 70%);
    border-radius: 50%;
}

/* 粒子动画 */
@keyframes float1 {
    0%, 100% { transform: translateY(0px) translateX(0px); opacity: 0; }
    10% { opacity: 1; }
    90% { opacity: 1; }
    100% { transform: translateY(-100vh) translateX(100px); opacity: 0; }
}

@keyframes float2 {
    0%, 100% { transform: translateY(0px) translateX(0px); opacity: 0; }
    10% { opacity: 0.8; }
    90% { opacity: 0.8; }
    100% { transform: translateY(-100vh) translateX(-100px); opacity: 0; }
}

@keyframes float3 {
    0%, 100% { transform: translateY(0px) translateX(0px); opacity: 0; }
    10% { opacity: 0.6; }
    90% { opacity: 0.6; }
    100% { transform: translateY(-100vh) translateX(50px); opacity: 0; }
}

/* ==================== 登录容器 ==================== */
.login-container {
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
    position: relative;
    z-index: 1;
}

.login-box {
    background: white;
    border-radius: 10px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
    width: 100%;
    max-width: 400px;
    padding: 40px;
    animation: slideIn 0.5s ease-out, float 6s ease-in-out infinite;
    animation-delay: 0s, 0.5s;
}

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

@keyframes float {
    0%, 100% {
        transform: translateY(0px);
        box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
    }
    50% {
        transform: translateY(-10px);
        box-shadow: 0 20px 50px rgba(0, 0, 0, 0.3);
    }
}

/* ==================== 登录头部 ==================== */
.login-header {
    text-align: center;
    margin-bottom: 30px;
}

.login-header h1 {
    font-size: 28px;
    color: #333;
    margin-bottom: 5px;
    font-weight: 600;
}

.login-header p {
    font-size: 14px;
    color: #999;
    letter-spacing: 1px;
}

/* ==================== 表单样式 ==================== */
.login-form {
    width: 100%;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    font-size: 14px;
    color: #333;
    margin-bottom: 8px;
    font-weight: 500;
}

.input-wrapper {
    position: relative;
    display: flex;
    align-items: center;
}

.input-icon {
    position: absolute;
    left: 12px;
    font-size: 18px;
    color: #667eea;
    pointer-events: none;
}

.input-wrapper input {
    width: 100%;
    padding: 12px 12px 12px 45px;
    border: 2px solid #e0e0e0;
    border-radius: 6px;
    font-size: 14px;
    transition: all 0.3s ease;
    outline: none;
}

.input-wrapper input:focus {
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.input-wrapper input::placeholder {
    color: #bbb;
}

.toggle-password {
    position: absolute;
    right: 12px;
    cursor: pointer;
    font-size: 18px;
    user-select: none;
    transition: opacity 0.3s ease;
}

.toggle-password:hover {
    opacity: 0.7;
}

/* ==================== 表单选项 ==================== */
.form-options {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 25px;
    font-size: 14px;
}

.remember-me {
    display: flex;
    align-items: center;
    cursor: pointer;
    color: #666;
    user-select: none;
}

.remember-me input[type="checkbox"] {
    margin-right: 6px;
    cursor: pointer;
    width: 16px;
    height: 16px;
}

.forgot-password {
    color: #667eea;
    text-decoration: none;
    transition: color 0.3s ease;
}

.forgot-password:hover {
    color: #764ba2;
    text-decoration: underline;
}

/* ==================== 登录按钮 ==================== */
.login-btn {
    width: 100%;
    padding: 12px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-bottom: 15px;
}

.login-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 20px rgba(102, 126, 234, 0.4);
}

.login-btn:active {
    transform: translateY(0);
}

.login-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

/* ==================== 消息提示 ==================== */
.error-message {
    color: #e74c3c;
    font-size: 13px;
    margin-bottom: 10px;
    padding: 10px;
    background-color: #fadbd8;
    border-left: 3px solid #e74c3c;
    border-radius: 3px;
    display: none;
}

.error-message.show {
    display: block;
    animation: shake 0.5s ease-in-out;
}

.success-message {
    color: #27ae60;
    font-size: 13px;
    margin-bottom: 10px;
    padding: 10px;
    background-color: #d5f4e6;
    border-left: 3px solid #27ae60;
    border-radius: 3px;
    display: none;
}

.success-message.show {
    display: block;
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-5px); }
    75% { transform: translateX(5px); }
}

/* ==================== 登录底部 ==================== */
.login-footer {
    text-align: center;
    margin-top: 30px;
    padding-top: 20px;
    border-top: 1px solid #e0e0e0;
    font-size: 12px;
    color: #999;
}

/* ==================== 平板设备响应式设计 (768px) ==================== */
@media (max-width: 768px) {
    .login-box {
        max-width: 90%;
        padding: 30px 25px;
    }

    .login-header h1 {
        font-size: 24px;
    }

    .form-group label {
        font-size: 13px;
    }

    .input-wrapper input {
        padding: 11px 11px 11px 40px;
        font-size: 16px; /* 防止iOS自动放大 */
    }

    .form-options {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }

    .forgot-password {
        align-self: flex-end;
    }
}

/* ==================== 手机设备响应式设计 (480px) ==================== */
@media (max-width: 480px) {
    html, body {
        background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    }

    .login-container {
        padding: 15px;
    }

    .login-box {
        max-width: 100%;
        padding: 25px 20px;
        border-radius: 8px;
    }

    .login-header h1 {
        font-size: 22px;
        margin-bottom: 3px;
    }

    .login-header p {
        font-size: 12px;
    }

    .form-group {
        margin-bottom: 18px;
    }

    .form-group label {
        font-size: 12px;
        margin-bottom: 6px;
    }

    .input-wrapper input {
        padding: 10px 10px 10px 38px;
        font-size: 16px;
        border-radius: 5px;
    }

    .input-icon {
        left: 10px;
        font-size: 16px;
    }

    .toggle-password {
        right: 10px;
        font-size: 16px;
    }

    .login-btn {
        padding: 11px;
        font-size: 15px;
        margin-bottom: 12px;
    }

    .login-footer {
        margin-top: 20px;
        padding-top: 15px;
        font-size: 11px;
    }

    .error-message,
    .success-message {
        font-size: 12px;
        padding: 8px;
    }
}

/* ==================== 超小屏幕 (320px) ==================== */
@media (max-width: 320px) {
    .login-box {
        padding: 20px 15px;
    }

    .login-header h1 {
        font-size: 20px;
    }

    .login-header p {
        font-size: 11px;
    }

    .form-group label {
        font-size: 11px;
    }

    .input-wrapper input {
        padding: 9px 9px 9px 35px;
        font-size: 14px;
    }

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

    .toggle-password {
        font-size: 14px;
    }

    .login-btn {
        padding: 10px;
        font-size: 14px;
    }
}

/* ==================== 大屏幕设备 (1200px+) ==================== */
@media (min-width: 1200px) {
    .login-box {
        max-width: 450px;
        padding: 50px;
    }

    .login-header h1 {
        font-size: 32px;
    }

    .form-group label {
        font-size: 15px;
    }

    .input-wrapper input {
        padding: 13px 13px 13px 48px;
        font-size: 15px;
    }

    .login-btn {
        padding: 13px;
        font-size: 17px;
    }
}