:root {
    --primary-color: #4361ee;
    --secondary-color: #3f37c9;
    --accent-color: #4cc9f0;
    --light-color: #f8f9fa;
    --dark-color: #212529;
    --success-color: #4ade80;
    --border-radius: 8px;
    --box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: #333;
    background: linear-gradient(135deg, #f5f7fa 0%, #e4edf5 100%);
    min-height: 100vh;
}

nav {
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 1rem 0;
    box-shadow: var(--box-shadow);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 20px;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    display: flex;
    align-items: center;
}

.logo-icon {
    margin-right: 10px;
    font-size: 1.8rem;
}

/* 主要内容区域 */
.container {
    max-width: 1200px;
    margin: 30px auto;
    padding: 0 20px;
}

header {
    text-align: center;
    margin-bottom: 30px;
    padding: 20px 0;
}

h1 {
    color: var(--primary-color);
    margin-bottom: 10px;
    font-size: 2.5rem;
}

.subtitle {
    color: #6c757d;
    font-size: 1.2rem;
}

.calculator-container {
    background: white;
    border-radius: var(--border-radius);
    padding: 30px;
    box-shadow: var(--box-shadow);
    margin-bottom: 30px;
    transition: var(--transition);
}

.calculator-container:hover {
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

.input-groups {
    margin-bottom: 20px;
}

.input-group {
    display: flex;
    margin-bottom: 20px;
    align-items: center;
    padding: 12px;
    background: #f8f9fa;
    border-radius: var(--border-radius);
    transition: var(--transition);
    position: relative;
}

.input-group:hover {
    background: #e9ecef;
}

.input-group-number {
    width: 36px;
    height: 36px;
    background: var(--primary-color);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    margin-right: 15px;
    flex-shrink: 0;
}

.time-inputs {
    display: flex;
    align-items: center;
    flex: 1;
}

.time-inputs input {
    width: 120px;
    padding: 14px 16px;
    border: 2px solid #dee2e6;
    border-radius: var(--border-radius);
    text-align: center;
    font-size: 18px;
    transition: var(--transition);
    min-width: 100px;
    height: 50px;
}

.time-inputs input:focus {
    border-color: var(--primary-color);
    outline: none;
    box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.2);
}

.time-separator {
    margin: 0 15px;
    font-weight: bold;
    color: var(--primary-color);
}

.add-button-container {
    display: flex;
    flex-direction: column;
    gap: 15px;
    margin: 25px 0;
    align-items: flex-start;
}

.button-row {
    display: flex;
    justify-content: flex-start;
    gap: 15px;
    flex-wrap: wrap;
}

.add-button {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 12px 25px;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 16px;
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    transition: var(--transition);
    margin: 0 5px;
}

.add-button:hover {
    background: var(--secondary-color);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

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

.remove-group-button {
    background: #e63946;
    color: white;
    border: none;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    cursor: pointer;
    font-size: 28px;
    font-weight: bold;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
    margin-left: 15px;
    flex-shrink: 0;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

.remove-group-button:hover {
    background: #c1121f;
    transform: scale(1.1);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.3);
}

.remove-group-button:active {
    transform: scale(0.95);
}

.remove-placeholder {
    width: 40px;
    height: 40px;
    margin-left: 15px;
    flex-shrink: 0;
}

.calculate-button {
    background: #e63946;
    color: white;
    border: none;
    padding: 18px 32px;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 20px;
    font-weight: 700;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
    width: auto;
    max-width: 300px;
    margin: 0 auto;
}

.calculate-button:hover {
    background: #c1121f;
    transform: translateY(-3px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.3);
}

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

.clear-button {
    background: #e9c46a;
    color: white;
    border: none;
    padding: 12px 25px;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 16px;
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    transition: var(--transition);
    margin: 0 5px;
    color: #333;
}

.clear-button:hover {
    background: #d4a94a;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

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

.add-button-icon,
.remove-button-icon,
.calculate-button-icon,
.clear-button-icon {
    margin-right: 8px;
    font-size: 1.2rem;
}

.results {
    margin-top: 30px;
    padding: 25px;
    background: linear-gradient(135deg, #4361ee 0%, #3a0ca3 100%);
    border-radius: var(--border-radius);
    color: white;
}

.results-header {
    text-align: center;
    margin-bottom: 20px;
    font-size: 1.5rem;
    font-weight: 600;
}

.result-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
}

.result-card {
    background: rgba(255, 255, 255, 0.1);
    border-radius: var(--border-radius);
    padding: 20px;
    text-align: center;
    backdrop-filter: blur(10px);
    transition: var(--transition);
}

.result-card:hover {
    transform: translateY(-5px);
    background: rgba(255, 255, 255, 0.15);
}

.result-label {
    font-weight: 600;
    margin-bottom: 10px;
    font-size: 1.1rem;
}

.result-value {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--accent-color);
}

.faq-section {
    background: white;
    border-radius: var(--border-radius);
    padding: 30px;
    box-shadow: var(--box-shadow);
    margin-bottom: 30px;
    transition: var(--transition);
}

.faq-section:hover {
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

.faq-section h2 {
    color: var(--primary-color);
    margin-bottom: 25px;
    text-align: center;
    font-size: 2rem;
}

.faq-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 25px;
}

.faq-item {
    padding: 20px;
    border-radius: var(--border-radius);
    background: #f8f9fa;
    transition: var(--transition);
}

.faq-item:hover {
    background: #e9ecef;
    transform: translateY(-3px);
}

.faq-question {
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 10px;
    font-size: 1.1rem;
}

.faq-answer {
    color: #495057;
    line-height: 1.7;
}

/* 页脚 */
footer {
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    color: white;
    text-align: center;
    padding: 30px 0;
    margin-top: 50px;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.copyright {
    margin-top: 10px;
    opacity: 0.8;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .nav-container {
        flex-direction: column;
        text-align: center;
    }

    h1 {
        font-size: 2rem;
    }

    .calculator-container,
    .faq-section {
        padding: 20px;
    }

    .time-inputs {
        flex-direction: row;
        align-items: center;
    }

    .time-inputs > div {
        margin-bottom: 0;
        width: auto;
        display: inline-block;
    }

    .time-inputs input {
        width: 100px;
        min-width: 90px;
        padding: 14px 16px;
        font-size: 16px;
        height: 48px;
    }

    .result-grid {
        grid-template-columns: 1fr;
    }

    .faq-grid {
        grid-template-columns: 1fr;
    }

    .input-group {
        padding: 10px;
    }
    
    .input-group-number {
        margin-right: 12px;
    }
    
    .remove-group-button {
        width: 36px;
        height: 36px;
        font-size: 24px;
    }
    
    .remove-placeholder {
        width: 36px;
        height: 36px;
    }
    
    .add-button-container {
        flex-direction: column;
        gap: 15px;
    }
}

@media (max-width: 480px) {
    .container {
        margin: 15px auto;
        padding: 0 10px;
    }

    .calculator-container,
    .faq-section {
        padding: 15px;
    }

    h1 {
        font-size: 1.8rem;
    }

    .result-value {
        font-size: 1.5rem;
    }
    
    .time-inputs {
        display: flex;
        justify-content: center;
    }
    
    .time-inputs input {
        width: 110px;
        min-width: 100px;
        padding: 14px 16px;
        font-size: 18px;
        height: 52px;
    }
    
    .time-separator {
        margin: 0 12px;
        font-size: 18px;
    }
    
    .input-group {
        padding: 8px;
    }
    
    .input-group-number {
        width: 30px;
        height: 30px;
        font-size: 0.9rem;
        margin-right: 10px;
    }
    
    .remove-group-button {
        width: 30px;
        height: 30px;
        font-size: 20px;
        margin-left: 10px;
    }
    
    .remove-placeholder {
        width: 30px;
        height: 30px;
        margin-left: 10px;
    }
    
    .add-button-container {
        gap: 12px;
    }
    
    .button-row {
        gap: 10px;
    }
    
    .calculate-button {
        padding: 16px 28px;
        font-size: 18px;
        max-width: 100%;
    }
}