/* Google Fonts */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;600;700&display=swap');

:root {
    --primary-color: #8b5cf6; /* Energetic Purple */
    --primary-hover: #7c3aed;
    --bg-color-light: #f3f4f6;
    --text-color-light: #1f2937;
    --card-bg-light: rgba(255, 255, 255, 0.8);
    
    --bg-color-dark: #111827;
    --text-color-dark: #f9fafb;
    --card-bg-dark: rgba(31, 41, 55, 0.8);

    --border-radius: 16px;
    --glass-border: 1px solid rgba(255, 255, 255, 0.1);
    --shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

body {
    font-family: 'Inter', sans-serif;
    margin: 0;
    padding: 0;
    background-color: var(--bg-color-light);
    color: var(--text-color-light);
    transition: background-color 0.3s, color 0.3s;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

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

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

/* Glassmorphism Card */
.glass-card {
    background: var(--card-bg-light);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-radius: var(--border-radius);
    border: var(--glass-border);
    box-shadow: var(--shadow);
    padding: 2.5rem;
    margin-bottom: 2rem;
    transition: transform 0.3s ease;
}

body.dark-mode .glass-card {
    background: var(--card-bg-dark);
}

.glass-card:hover {
    transform: translateY(-5px);
}

/* Forms and Inputs */
.input-group {
    margin-bottom: 1.5rem;
}

label {
    display: block;
    font-weight: 600;
    margin-bottom: 0.5rem;
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--primary-color);
}

textarea {
    width: 100%;
    padding: 1rem;
    border-radius: 12px;
    border: 2px solid transparent;
    background-color: rgba(0, 0, 0, 0.05);
    color: inherit;
    font-family: inherit;
    font-size: 1.1rem;
    resize: vertical;
    transition: all 0.3s ease;
    box-sizing: border-box;
}

body.dark-mode textarea {
    background-color: rgba(255, 255, 255, 0.05);
}

textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 4px rgba(139, 92, 246, 0.2);
}

/* Buttons */
.btn-primary {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 1rem 2rem;
    border-radius: 50px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 6px rgba(139, 92, 246, 0.3);
    text-decoration: none;
    display: inline-block;
}

.btn-primary:hover {
    background-color: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(139, 92, 246, 0.4);
}

/* Invoice Specific */
.invoice-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 2px solid var(--primary-color);
    padding-bottom: 1rem;
    margin-bottom: 2rem;
}

.invoice-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin: 0;
    background: linear-gradient(135deg, var(--primary-color), #d946ef);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.invoice-details {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin-bottom: 2rem;
}

.detail-box p {
    margin: 0.5rem 0;
    font-size: 1.1rem;
}

.amount-highlight {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.alert {
    padding: 1rem;
    border-radius: 8px;
    margin-bottom: 1rem;
    background-color: #fee2e2;
    color: #991b1b;
    border: 1px solid #f87171;
}

/* Theme Toggle */
.theme-toggle {
    position: absolute;
    top: 2rem;
    right: 2rem;
    background: none;
    border: none;
    color: inherit;
    font-size: 1.5rem;
    cursor: pointer;
    transition: transform 0.3s;
}

.theme-toggle:hover {
    transform: rotate(15deg) scale(1.1);
}