:root {
    --primary-pink: #e91e63;
    --primary-dark: #c2185b;
    --primary-light: #f8bbd0;
    --secondary-blue: #2196f3;
    --success-green: #4caf50;
    --warning-orange: #ff9800;
    --bg-light: #fef7f9;
    --bg-dark: #1a1a2e;
    --text-light: #333;
    --text-dark: #eee;
    --card-light: #fff;
    --card-dark: #16213e;
    --shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    --shadow-hover: 0 15px 40px rgba(0, 0, 0, 0.15);
    --border-radius: 16px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--bg-light);
    color: var(--text-light);
    line-height: 1.6;
    transition: var(--transition);
}

body.dark {
    background: var(--bg-dark);
    color: var(--text-dark);
}

/* Navbar */
.navbar {
    background: var(--card-light);
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 1000;
    transition: var(--transition);
}

body.dark .navbar {
    background: var(--card-dark);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
}

.logo i {
    color: var(--primary-pink);
    margin-right: 8px;
}

.logo .highlight {
    color: var(--primary-pink);
}

.theme-toggle {
    cursor: pointer;
    font-size: 1.3rem;
    padding: 8px;
    border-radius: 50%;
    transition: var(--transition);
}

.theme-toggle:hover {
    background: var(--primary-light);
    transform: rotate(15deg);
}

/* Container */
.container {
    max-width: 1200px;
    margin: 2rem auto;
    padding: 0 1rem;
}

/* Calculator Card */
.calculator-card {
    background: var(--card-light);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    overflow: hidden;
    transition: var(--transition);
}

body.dark .calculator-card {
    background: var(--card-dark);
}

.card-header {
    background: linear-gradient(135deg, var(--primary-pink), var(--primary-dark));
    color: white;
    padding: 2rem;
    text-align: center;
}

.card-header h1 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

/* Input Methods */
.input-methods {
    padding: 2rem;
}

.method-buttons {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.method-btn {
    flex: 1;
    padding: 0.75rem;
    border: 2px solid var(--primary-light);
    background: transparent;
    border-radius: 8px;
    cursor: pointer;
    transition: var(--transition);
    font-weight: 500;
}

.method-btn.active {
    background: var(--primary-pink);
    color: white;
    border-color: var(--primary-pink);
}

.input-group {
    margin-bottom: 1.5rem;
}

.input-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.date-input, .select-input {
    width: 100%;
    padding: 0.75rem;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    font-size: 1rem;
    transition: var(--transition);
}

body.dark .date-input,
body.dark .select-input {
    background: #2a2a3e;
    border-color: #3a3a5e;
    color: white;
}

.date-input:focus, .select-input:focus {
    outline: none;
    border-color: var(--primary-pink);
}

.hidden {
    display: none;
}

.calculate-btn {
    width: 100%;
    padding: 1rem;
    background: linear-gradient(135deg, var(--primary-pink), var(--primary-dark));
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
}

.calculate-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
}

/* Results Section */
.results-section {
    padding: 2rem;
    animation: fadeInUp 0.5s ease;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.results-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.result-card {
    background: linear-gradient(135deg, #f5f5f5, #fff);
    padding: 1.5rem;
    border-radius: 12px;
    text-align: center;
    transition: var(--transition);
    border: 1px solid rgba(0, 0, 0, 0.05);
}

body.dark .result-card {
    background: linear-gradient(135deg, #1e1e2e, #2a2a3e);
}

.result-card i {
    font-size: 2rem;
    color: var(--primary-pink);
    margin-bottom: 0.5rem;
}

.result-value {
    font-size: 1.5rem;
    font-weight: 700;
    margin: 0.5rem 0;
    color: var(--primary-pink);
}

/* Progress Bar */
.progress-container {
    margin: 2rem 0;
}

.progress-label {
    display: flex;
    justify-content: space-between;
    margin-bottom: 0.5rem;
}

.progress-bar {
    background: #e0e0e0;
    height: 30px;
    border-radius: 15px;
    overflow: hidden;
}

body.dark .progress-bar {
    background: #2a2a3e;
}

.progress-fill {
    background: linear-gradient(90deg, var(--primary-pink), var(--secondary-blue));
    height: 100%;
    width: 0%;
    transition: width 0.5s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 600;
}

/* Countdown Card */
.countdown-card {
    background: linear-gradient(135deg, var(--primary-light), #fff);
    padding: 1.5rem;
    border-radius: 12px;
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 2rem;
}

body.dark .countdown-card {
    background: linear-gradient(135deg, #1e1e2e, #2a2a3e);
}

.countdown-card i {
    font-size: 2rem;
    color: var(--primary-pink);
}

.countdown-card span {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-pink);
}

/* Milestones */
.milestones-section, .week-info-section {
    margin: 2rem 0;
}

.milestones-list {
    display: grid;
    gap: 1rem;
    margin-top: 1rem;
}

.milestone-item {
    padding: 1rem;
    background: #f5f5f5;
    border-left: 4px solid var(--primary-pink);
    border-radius: 8px;
    transition: var(--transition);
}

body.dark .milestone-item {
    background: #1e1e2e;
}

.milestone-item.completed {
    opacity: 0.6;
    border-left-color: var(--success-green);
}

.week-info-card {
    background: #f5f5f5;
    padding: 1.5rem;
    border-radius: 12px;
    margin-top: 1rem;
}

body.dark .week-info-card {
    background: #1e1e2e;
}

/* Action Buttons */
.action-buttons {
    display: flex;
    gap: 1rem;
    margin-top: 2rem;
}

.action-btn {
    flex: 1;
    padding: 0.75rem;
    background: var(--primary-pink);
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: var(--transition);
    font-weight: 500;
}

.action-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

/* Info Section */
.info-section {
    background: #f9f9f9;
    padding: 2rem;
    border-top: 1px solid #e0e0e0;
}

body.dark .info-section {
    background: #1a1a2e;
    border-top-color: #2a2a3e;
}

.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-top: 1rem;
}

.info-item {
    padding: 1rem;
}

.info-item strong {
    color: var(--primary-pink);
    display: block;
    margin-bottom: 0.5rem;
}

/* Footer */
.footer {
    text-align: center;
    padding: 2rem;
    background: var(--card-light);
    margin-top: 2rem;
}

body.dark .footer {
    background: var(--card-dark);
}

/* Responsive */
@media (max-width: 768px) {
    .card-header h1 {
        font-size: 1.5rem;
    }
    
    .results-grid {
        grid-template-columns: 1fr;
    }
    
    .action-buttons {
        flex-direction: column;
    }
    
    .method-buttons {
        flex-direction: column;
    }
}