/* --- 优化后的 Modern Dark Theme for Project 2 --- */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}
body {
    font-family: 'Inter', 'Roboto', 'Segoe UI', Arial, sans-serif;
    background: linear-gradient(135deg, #181c24 0%, #23283a 100%);
    color: #e3e6eb;
    line-height: 1.7;
    min-height: 100vh;
}
header {
    background: rgba(35,40,58,0.98);
    color: #fff;
    padding: 1.3rem 2.5rem 1.1rem 2.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 4px 18px rgba(0,0,0,0.22);
    border-bottom: 1.5px solid #31374a;
    position: sticky;
    top: 0;
    z-index: 10;
    backdrop-filter: blur(6px);
}
.logo {
    font-size: 2.1rem;
    font-weight: 800;
    letter-spacing: 2.5px;
    color: #4fd1c5;
    text-shadow: 0 2px 8px #222b36;
}
nav ul {
    display: flex;
    list-style: none;
}
nav ul li {
    margin-left: 2.2rem;
}
nav ul li a {
    color: #e3e6eb;
    text-decoration: none;
    font-weight: 500;
    padding: 0.5rem 1.2rem;
    border-radius: 8px;
    transition: background 0.18s, color 0.18s, box-shadow 0.18s;
    box-shadow: 0 1px 4px rgba(79,209,197,0.04);
    letter-spacing: 0.5px;
}
nav ul li a:hover, nav ul li a.active {
    background: linear-gradient(90deg, #4fd1c5 0%, #38b2ac 100%);
    color: #181c24;
    box-shadow: 0 2px 12px #4fd1c555;
}
main {
    max-width: 950px;
    margin: 2.8rem auto 2.5rem auto;
    padding: 2.2rem 2rem;
    background: rgba(35,40,58,0.98);
    border-radius: 22px;
    box-shadow: 0 8px 40px 0 rgba(0,0,0,0.22);
    border: 1.5px solid #23283a;
}
.hero-slider {
    position: relative;
    height: 320px;
    overflow: hidden;
    margin-bottom: 2.2rem;
    border-radius: 18px;
    box-shadow: 0 6px 32px rgba(0,0,0,0.28);
}
.slide {
    position: absolute;
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 2.3rem;
    color: #fff;
    background-size: cover;
    background-position: center;
    opacity: 0;
    transition: opacity 1s;
    z-index: 1;
    border-radius: 18px;
    text-shadow: 0 2px 12px #000a;
}
.slide.active {
    opacity: 1;
    z-index: 2;
}
.product-intro, .cta-section, .print-container,
.login-container, .register-container, .contact-container, .account-container {
    text-align: left;
    padding: 1.7rem 0 1.2rem 0;
}
.product-intro h2 {
    margin-bottom: 1.1rem;
    color: #4fd1c5;
    font-weight: 700;
    letter-spacing: 1px;
}
.cta-section {
    display: flex;
    justify-content: flex-start;
    gap: 1.7rem;
}
.btn {
    padding: 0.8rem 2.2rem;
    background: linear-gradient(90deg, #4fd1c5 0%, #38b2ac 100%);
    color: #181c24;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    font-size: 1.13rem;
    font-weight: 700;
    box-shadow: 0 2px 12px #4fd1c533, 0 1.5px 0 #23283a;
    transition: background 0.18s, color 0.18s, transform 0.12s, box-shadow 0.18s;
    letter-spacing: 0.5px;
}
.btn:hover {
    background: linear-gradient(90deg, #38b2ac 0%, #4fd1c5 100%);
    color: #fff;
    transform: translateY(-2px) scale(1.045);
    box-shadow: 0 4px 24px #4fd1c577;
}
fieldset {
    border: 1.5px solid #2d334d;
    border-radius: 14px;
    margin-bottom: 2.2rem;
    padding: 1.7rem 1.2rem;
    background: #1a1e29ee;
    box-shadow: 0 2px 12px #23283a22;
}
legend {
    color: #4fd1c5;
    font-weight: 700;
    padding: 0 0.8rem;
    font-size: 1.13rem;
    letter-spacing: 0.5px;
}
.form-group {
    display: flex;
    align-items: center;
    margin-bottom: 1.3rem;
    justify-content: flex-start;
}
.form-group label {
    flex: 0 0 140px;
    margin-bottom: 0;
    text-align: right;
    margin-right: 1.3rem;
    font-weight: 600;
    color: #b5b5b5;
    letter-spacing: 0.2px;
}
.form-group input,
.form-group textarea {
    flex: 1 1 auto;
    width: auto;
    min-width: 0;
    padding: 0.8rem;
    border: 2.5px solid #3ed6c2;
    border-radius: 8px;
    font-size: 1.05rem;
    background: #23283a;
    color: #e3e6eb;
    transition: border 0.18s, background 0.18s, box-shadow 0.18s;
    box-shadow: 0 1px 6px #23283a33;
}
.form-group input:focus,
.form-group textarea:focus {
    border: 2.5px solid #4fd1c5;
    background: #1a1e29;
    outline: none;
    box-shadow: 0 2px 12px #4fd1c555;
}
.order-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 1.7rem;
    background: #1a1e29ee;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 2px 12px #23283a22;
}
.order-table th, .order-table td {
    padding: 1.1rem 0.8rem;
    border-bottom: 1.5px solid #2d334d;
    text-align: left;
}
.order-table th {
    background: #23283a;
    color: #4fd1c5;
    font-weight: 700;
    letter-spacing: 0.5px;
}
.order-table tr:last-child td {
    border-bottom: none;
}
.hidden {
    display: none;
}
footer {
    background: rgba(35,40,58,0.98);
    color: #b5b5b5;
    text-align: center;
    padding: 1.3rem;
    margin-top: 2.7rem;
    border-top: 1.5px solid #31374a;
    font-size: 1.05rem;
    border-radius: 0 0 18px 18px;
    box-shadow: 0 -2px 12px #23283a22;
}
@media (max-width: 950px) {
    main {
        max-width: 99vw;
        padding: 1.2rem 0.5rem;
    }
}
@media (max-width: 700px) {
    main {
        padding: 0.7rem 0.1rem;
    }
    .hero-slider {
        height: 180px;
    }
}
@media (max-width: 600px) {
    .form-group {
        flex-direction: column;
        align-items: stretch;
    }
    .form-group label {
        text-align: left;
        margin-bottom: 0.5rem;
        margin-right: 0;
    }
}