.sleep-calculator-container {
    --primary-color: #6d5dd3;
    --secondary-color: #8e7ceb;
    --background-color: #f8f9fa;
    --text-color: #333;
    --card-bg: #ffffff;
    --accent-color: #ff7d50;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
    padding: 20px;
    min-height: 100vh;
}

/* Theme Variables */
.sleep-calculator-container.theme-cozy-night {
    --primary-color: #5a67d8;
    --secondary-color: #4c51bf;
    --background-color: #f8fafc;
    --text-color: #2d3748;
    --card-bg: #ffffff;
    --accent-color: #ed8936;
}

.sleep-calculator-container.theme-midnight-plum {
    --primary-color: #6b46c1;
    --secondary-color: #553c9a;
    --background-color: #1a202c;
    --text-color: #e2e8f0;
    --card-bg: #2d3748;
    --accent-color: #9f7aea;
}

.sleep-calculator-container.theme-plum-candy {
    --primary-color: #d53f8c;
    --secondary-color: #ed64a6;
    --background-color: #fff5f7;
    --text-color: #702459;
    --card-bg: #fed7e2;
    --accent-color: #f687b3;
}

.sleep-calculator-container.theme-twilight-rose {
    --primary-color: #ed8936;
    --secondary-color: #f6ad55;
    --background-color: #fdf2f8;
    --text-color: #702459;
    --card-bg: #fbb6ce;
    --accent-color: #f687b3;
}

.sleep-calculator-container * {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    transition: background-color 0.3s, color 0.3s;
}

.sleep-calculator-container .container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

.sleep-calculator-container header {
    text-align: center;
    margin-bottom: 30px;
    padding: 20px;
    border-radius: 15px;
    background-color: var(--card-bg);
    box-shadow: var(--shadow);
    position: relative;
}

.sleep-calculator-container .logo-container {
    display: flex;
    justify-content: center;
    align-items: center;
    margin-bottom: 15px;
    gap: 15px;
}

.sleep-calculator-container .logo {
    width: 70px;
    height: 70px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 28px;
    font-weight: bold;
    box-shadow: var(--shadow);
}

.sleep-calculator-container .logo-placeholder {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
    opacity: 0.7;
}

.sleep-calculator-container .logo-btn {
    padding: 8px 15px;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 0.9rem;
    display: flex;
    align-items: center;
    gap: 5px;
}

.sleep-calculator-container .logo-btn:hover {
    background-color: var(--secondary-color);
}

.sleep-calculator-container h1 {
    color: var(--primary-color);
    margin-bottom: 15px;
    font-size: 2.5rem;
}

.sleep-calculator-container .tagline {
    font-size: 1.2rem;
    margin-bottom: 20px;
    color: var(--secondary-color);
}

.sleep-calculator-container .controls {
    display: flex;
    justify-content: center;
    gap: 20px;
    flex-wrap: wrap;
    margin-bottom: 20px;
}

.sleep-calculator-container .control-group {
    display: flex;
    align-items: center;
    gap: 10px;
    background: rgba(255, 255, 255, 0.1);
    padding: 10px 15px;
    border-radius: 50px;
}

.sleep-calculator-container .language-selector, 
.sleep-calculator-container .theme-selector {
    padding: 8px 15px;
    border-radius: 50px;
    border: 2px solid var(--secondary-color);
    background-color: var(--card-bg);
    color: var(--text-color);
    cursor: pointer;
    font-weight: 500;
}

.sleep-calculator-container .datetime {
    display: flex;
    flex-direction: column;
    align-items: center;
    margin: 15px 0;
    padding: 10px 20px;
    background: rgba(0, 0, 0, 0.05);
    border-radius: 10px;
    font-family: 'Courier New', monospace;
}

.sleep-calculator-container .time {
    font-size: 2rem;
    font-weight: bold;
    color: var(--primary-color);
}

.sleep-calculator-container .date {
    font-size: 1.2rem;
    color: var(--secondary-color);
}

.sleep-calculator-container .calculator-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 25px;
    margin-bottom: 30px;
}

.sleep-calculator-container .calculator-card {
    background-color: var(--card-bg);
    border-radius: 15px;
    padding: 25px;
    box-shadow: var(--shadow);
    text-align: center;
    position: relative;
}

.sleep-calculator-container .card-icon {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 15px;
}

.sleep-calculator-container h2 {
    color: var(--primary-color);
    margin-bottom: 20px;
    font-size: 1.8rem;
}

.sleep-calculator-container .time-input {
    width: 100%;
    padding: 12px;
    margin-bottom: 20px;
    border: 2px solid var(--secondary-color);
    border-radius: 10px;
    font-size: 1.1rem;
    background-color: var(--card-bg);
    color: var(--text-color);
}

.sleep-calculator-container .btn {
    padding: 12px 25px;
    border: none;
    border-radius: 10px;
    font-size: 1.1rem;
    cursor: pointer;
    font-weight: 600;
    transition: transform 0.2s, box-shadow 0.2s;
}

.sleep-calculator-container .btn-primary {
    background-color: var(--primary-color);
    color: white;
}

.sleep-calculator-container .btn-secondary {
    background-color: var(--accent-color);
    color: white;
}

.sleep-calculator-container .btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.15);
}

.sleep-calculator-container .results {
    margin-top: 20px;
    padding: 15px;
    border-radius: 10px;
    background-color: rgba(0, 0, 0, 0.05);
    text-align: left;
}

.sleep-calculator-container .result-title {
    font-weight: 600;
    margin-bottom: 10px;
    color: var(--primary-color);
}

.sleep-calculator-container .result-times {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    justify-content: center;
}

.sleep-calculator-container .time-chip {
    background-color: var(--secondary-color);
    color: white;
    padding: 8px 15px;
    border-radius: 50px;
    font-size: 0.9rem;
}

.sleep-calculator-container .action-buttons {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin: 30px 0;
}

.sleep-calculator-container .ad-container {
    background-color: var(--card-bg);
    border-radius: 15px;
    padding: 20px;
    text-align: center;
    margin: 30px 0;
    box-shadow: var(--shadow);
}

.sleep-calculator-container .ad-placeholder {
    width: 100%;
    height: 150px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.2rem;
    font-weight: 600;
}

.sleep-calculator-container .sleep-tips {
    background-color: var(--card-bg);
    border-radius: 15px;
    padding: 25px;
    box-shadow: var(--shadow);
    margin: 30px 0;
}

.sleep-calculator-container .sleep-tips h2 {
    text-align: center;
    margin-bottom: 20px;
}

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

.sleep-calculator-container .tip-card {
    background: rgba(0, 0, 0, 0.03);
    padding: 15px;
    border-radius: 10px;
    border-left: 4px solid var(--primary-color);
}

.sleep-calculator-container .notification {
    position: fixed;
    bottom: 20px;
    right: 20px;
    padding: 15px 20px;
    background-color: var(--primary-color);
    color: white;
    border-radius: 10px;
    box-shadow: var(--shadow);
    transform: translateY(100px);
    opacity: 0;
    transition: transform 0.3s, opacity 0.3s;
    z-index: 1000;
}

.sleep-calculator-container .notification.show {
    transform: translateY(0);
    opacity: 1;
}

.sleep-calculator-container .coming-soon {
    font-size: 0.8rem;
    color: var(--secondary-color);
    font-style: italic;
}

@media (max-width: 768px) {
    .sleep-calculator-container .calculator-container {
        grid-template-columns: 1fr;
    }
    
    .sleep-calculator-container .controls {
        flex-direction: column;
        align-items: center;
    }

    .sleep-calculator-container .logo-container {
        flex-direction: column;
    }

    .sleep-calculator-container .time {
        font-size: 1.5rem;
    }

    .sleep-calculator-container .date {
        font-size: 1rem;
    }
}