/* ===== CSS RESET & BASE ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Color Palette */
    --purple-400: hsl(270, 70%, 70%);
    --purple-500: hsl(270, 70%, 60%);
    --purple-600: hsl(270, 60%, 50%);
    --pink-400: hsl(330, 80%, 65%);
    --pink-500: hsl(330, 80%, 55%);
    --blue-400: hsl(240, 70%, 70%);
    --cyan-400: hsl(190, 70%, 60%);
    
    /* Glass Effect */
    --glass-bg: rgba(255, 255, 255, 0.08);
    --glass-border: rgba(255, 255, 255, 0.18);
    --glass-shadow: rgba(0, 0, 0, 0.1);
    
    /* Text Colors */
    --text-primary: rgba(255, 255, 255, 0.95);
    --text-secondary: rgba(255, 255, 255, 0.7);
    --text-tertiary: rgba(255, 255, 255, 0.5);
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    
    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 16px;
    --radius-lg: 24px;
    
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    min-height: 100vh;
    background: linear-gradient(135deg, 
        hsl(260, 60%, 20%) 0%, 
        hsl(280, 50%, 15%) 25%,
        hsl(300, 60%, 20%) 50%,
        hsl(320, 50%, 18%) 75%,
        hsl(340, 60%, 22%) 100%
    );
    background-attachment: fixed;
    color: var(--text-primary);
    overflow-x: hidden;
    position: relative;
}

body::before {
    content: '';
    position: fixed;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: 
        radial-gradient(circle at 20% 50%, rgba(167, 139, 250, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(236, 72, 153, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 60% 80%, rgba(59, 130, 246, 0.1) 0%, transparent 50%);
    animation: gradientShift 20s ease infinite;
    z-index: -1;
}

@keyframes gradientShift {
    0%, 100% { transform: translate(0, 0) rotate(0deg); }
    33% { transform: translate(-5%, -5%) rotate(120deg); }
    66% { transform: translate(5%, 5%) rotate(240deg); }
}

/* ===== LAYOUT ===== */
.container {
    max-width: 900px;
    margin: 0 auto;
    padding: var(--spacing-lg) var(--spacing-md);
    min-height: 100vh;
}

/* ===== GLASS CARD ===== */
.glass-card {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
    box-shadow: 
        0 8px 32px 0 var(--glass-shadow),
        inset 0 1px 0 0 rgba(255, 255, 255, 0.1);
    transition: all var(--transition-normal);
    animation: fadeInUp 0.6s ease forwards;
    opacity: 0;
}

.glass-card:hover {
    transform: translateY(-2px);
    box-shadow: 
        0 12px 40px 0 rgba(0, 0, 0, 0.15),
        inset 0 1px 0 0 rgba(255, 255, 255, 0.15);
    border-color: rgba(255, 255, 255, 0.25);
}

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

.glass-card:nth-child(1) { animation-delay: 0.1s; }
.glass-card:nth-child(2) { animation-delay: 0.2s; }
.glass-card:nth-child(3) { animation-delay: 0.3s; }
.glass-card:nth-child(4) { animation-delay: 0.4s; }

/* ===== HEADER ===== */
.header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
    animation: fadeInUp 0.6s ease forwards;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
}

.logo svg {
    animation: rotate 20s linear infinite;
}

@keyframes rotate {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

.logo h1 {
    font-size: 2.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--purple-400), var(--pink-400));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.tagline {
    font-size: 1.1rem;
    color: var(--text-secondary);
    font-weight: 300;
}

/* ===== TYPOGRAPHY ===== */
h2 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.section-title {
    font-size: 1.75rem;
    font-weight: 600;
    margin-bottom: var(--spacing-lg);
    text-align: center;
    background: linear-gradient(135deg, var(--purple-400), var(--pink-400));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* ===== INPUTS ===== */
.input-group {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-md);
}

.input-wrapper {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.input-wrapper.flex-1 {
    grid-column: span 1;
}

.input-wrapper.flex-2 {
    grid-column: span 2;
}

label {
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

input {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-sm);
    padding: 0.875rem 1rem;
    font-size: 1rem;
    color: var(--text-primary);
    font-family: 'Inter', sans-serif;
    transition: all var(--transition-fast);
    outline: none;
}

input:focus {
    background: rgba(255, 255, 255, 0.08);
    border-color: var(--purple-400);
    box-shadow: 0 0 0 3px rgba(167, 139, 250, 0.1);
}

input::placeholder {
    color: var(--text-tertiary);
}

/* ===== HOURLY RATE DISPLAY ===== */
.hourly-rate-display {
    background: linear-gradient(135deg, 
        rgba(167, 139, 250, 0.2) 0%, 
        rgba(236, 72, 153, 0.2) 100%
    );
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: var(--radius-md);
    padding: var(--spacing-lg);
    text-align: center;
    margin-top: var(--spacing-md);
}

.rate-label {
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: var(--spacing-xs);
}

.rate-value {
    font-size: 2.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--purple-400), var(--pink-400));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.9; transform: scale(1.02); }
}

/* ===== BUTTONS ===== */
.btn-primary {
    background: linear-gradient(135deg, var(--purple-500), var(--pink-500));
    border: none;
    border-radius: var(--radius-sm);
    padding: 1rem 2rem;
    font-size: 1rem;
    font-weight: 600;
    color: white;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    transition: all var(--transition-fast);
    box-shadow: 0 4px 15px rgba(167, 139, 250, 0.3);
    width: 100%;
    font-family: 'Inter', sans-serif;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(167, 139, 250, 0.4);
}

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

.btn-delete {
    background: rgba(239, 68, 68, 0.2);
    border: 1px solid rgba(239, 68, 68, 0.3);
    border-radius: var(--radius-sm);
    padding: 0.5rem 0.75rem;
    color: #fca5a5;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
    font-size: 0.875rem;
    font-weight: 500;
}

.btn-delete:hover {
    background: rgba(239, 68, 68, 0.3);
    border-color: rgba(239, 68, 68, 0.5);
    color: #fee2e2;
}

/* ===== SUMMARY ===== */
.summary-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-md);
}

.summary-item {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    text-align: center;
    transition: all var(--transition-fast);
}

.summary-item:hover {
    background: rgba(255, 255, 255, 0.08);
    transform: scale(1.02);
}

.summary-label {
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: var(--spacing-xs);
}

.summary-value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
}

.summary-value.highlight {
    background: linear-gradient(135deg, var(--purple-400), var(--pink-400));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* ===== EXPENSES ===== */
.expenses-section {
    animation: fadeInUp 0.6s ease forwards;
}

.expenses-list {
    display: grid;
    gap: var(--spacing-md);
}

.expense-item {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    display: grid;
    grid-template-columns: 1fr auto;
    gap: var(--spacing-md);
    align-items: center;
    transition: all var(--transition-fast);
    animation: slideIn 0.4s ease forwards;
    transform: translateX(-20px);
    opacity: 0;
}

@keyframes slideIn {
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

.expense-item:hover {
    border-color: rgba(255, 255, 255, 0.3);
    transform: translateX(4px);
}

.expense-info h3 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-xs);
}

.expense-details {
    display: flex;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.expense-detail {
    display: flex;
    flex-direction: column;
}

.detail-label {
    font-size: 0.75rem;
    color: var(--text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.detail-value {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
}

.detail-value.hours {
    background: linear-gradient(135deg, var(--cyan-400), var(--blue-400));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.detail-value.amount {
    color: var(--purple-400);
}

/* ===== EMPTY STATE ===== */
.empty-state {
    text-align: center;
    padding: var(--spacing-xl) var(--spacing-lg);
    animation: fadeInUp 0.6s ease forwards;
}

.empty-state svg {
    margin-bottom: var(--spacing-lg);
    opacity: 0.6;
}

.empty-state h3 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
}

.empty-state p {
    font-size: 1rem;
    color: var(--text-secondary);
    max-width: 500px;
    margin: 0 auto;
    line-height: 1.6;
}

/* ===== FOOTER ===== */
.footer {
    text-align: center;
    padding: var(--spacing-lg) 0;
    color: var(--text-tertiary);
    font-size: 0.875rem;
}

/* ===== RESPONSIVE ===== */
@media (max-width: 768px) {
    .container {
        padding: var(--spacing-md) var(--spacing-sm);
    }
    
    .logo h1 {
        font-size: 2rem;
    }
    
    .input-group {
        grid-template-columns: 1fr;
    }
    
    .input-wrapper.flex-1,
    .input-wrapper.flex-2 {
        grid-column: span 1;
    }
    
    .summary-grid {
        grid-template-columns: 1fr;
    }
    
    .expense-item {
        grid-template-columns: 1fr;
    }
    
    .rate-value {
        font-size: 2rem;
    }
}

@media (max-width: 480px) {
    .logo h1 {
        font-size: 1.75rem;
    }
    
    .tagline {
        font-size: 1rem;
    }
    
    h2 {
        font-size: 1.25rem;
    }
    
    .glass-card {
        padding: var(--spacing-md);
    }
}