:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --primary-light: #e0e7ff;
    --bg-color: #f8fafc;
    --card-bg: rgba(255, 255, 255, 0.9);
    --text-main: #1e293b;
    --text-muted: #64748b;
    --border-color: #e2e8f0;
    --success-color: #10b981;
    --radius-lg: 20px;
    --radius-md: 12px;
    --radius-sm: 8px;
    --shadow-sm: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -1px rgba(0, 0, 0, 0.03);
    --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.05), 0 10px 10px -5px rgba(0, 0, 0, 0.02);
    --transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    background-color: var(--bg-color);
    background-image: 
        radial-gradient(at 0% 0%, hsla(253,16%,7%,0) 0, transparent 50%), 
        radial-gradient(at 50% 0%, hsla(225,39%,30%,0.05) 0, transparent 50%), 
        radial-gradient(at 100% 0%, hsla(339,49%,30%,0.05) 0, transparent 50%);
    color: var(--text-main);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
    line-height: 1.5;
}

.calculator-container {
    width: 100%;
    max-width: 600px;
}

.calculator-card {
    background: var(--card-bg);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid rgba(255, 255, 255, 0.5);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    padding: 40px;
    position: relative;
    overflow: hidden;
}

/* Subtle accent line on top */
.calculator-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, #6366f1, #a855f7, #ec4899);
}

.card-header {
    text-align: center;
    margin-bottom: 32px;
}

.logo-placeholder {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 48px;
    background: var(--primary-light);
    color: var(--primary-color);
    border-radius: var(--radius-md);
    margin-bottom: 16px;
}

h1 {
    font-size: 24px;
    font-weight: 700;
    color: var(--text-main);
    margin-bottom: 8px;
    letter-spacing: -0.025em;
}

.subtitle {
    color: var(--text-muted);
    font-size: 14px;
}

.form-group {
    margin-bottom: 24px;
}

label {
    display: block;
    font-size: 14px;
    font-weight: 600;
    color: var(--text-main);
    margin-bottom: 10px;
}

/* Custom Date Input */
.date-input {
    width: 100%;
    padding: 14px 16px;
    font-size: 16px;
    font-family: inherit;
    color: var(--text-main);
    background-color: #fff;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    transition: var(--transition);
    outline: none;
    box-shadow: var(--shadow-sm);
    cursor: pointer;
}

.date-input::placeholder {
    color: var(--text-muted);
}

.date-input:hover {
    border-color: #cbd5e1;
}

.date-input:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

/* Custom Radio Groups */
.radio-group {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
}

.radio-group.frequency-group {
    grid-template-columns: repeat(4, 1fr);
}

.radio-group.weekdays-group {
    grid-template-columns: repeat(7, 1fr);
    gap: 8px;
}

.radio-card {
    position: relative;
    cursor: pointer;
    display: block;
}

.radio-card input[type="radio"],
.radio-card input[type="checkbox"] {
    position: absolute;
    opacity: 0;
    width: 0;
    height: 0;
}

.radio-content {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 14px 12px;
    background-color: #fff;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 15px;
    font-weight: 500;
    color: var(--text-muted);
    transition: var(--transition);
    box-shadow: var(--shadow-sm);
    user-select: none;
    text-align: center;
}

.radio-card:hover .radio-content {
    border-color: #cbd5e1;
    background-color: #f8fafc;
}

.radio-card input[type="radio"]:checked + .radio-content,
.radio-card input[type="checkbox"]:checked + .radio-content {
    background-color: var(--primary-light);
    border-color: var(--primary-color);
    color: var(--primary-hover);
    font-weight: 600;
    box-shadow: 0 0 0 1px var(--primary-color);
}

.radio-card input[type="radio"]:focus-visible + .radio-content,
.radio-card input[type="checkbox"]:focus-visible + .radio-content {
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.3);
}

/* Result Section */
.result-section {
    margin-top: 32px;
    padding-top: 32px;
    border-top: 1px dashed var(--border-color);
}

.deadline-box {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-hover));
    border-radius: var(--radius-md);
    padding: 24px;
    text-align: center;
    color: white;
    margin-bottom: 24px;
    box-shadow: 0 10px 15px -3px rgba(99, 102, 241, 0.3);
    transform: translateY(0);
    transition: var(--transition);
    cursor: pointer;
}

.deadline-box:hover {
    transform: translateY(-2px);
    box-shadow: 0 15px 20px -3px rgba(99, 102, 241, 0.4);
}

.deadline-label {
    display: block;
    font-size: 14px;
    font-weight: 500;
    opacity: 0.9;
    margin-bottom: 8px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.deadline-date {
    font-size: 28px;
    font-weight: 700;
    letter-spacing: -0.025em;
}

/* Message Template */
.message-template-container {
    background-color: #f1f5f9;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    overflow: hidden;
}

.message-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 16px;
    background-color: #e2e8f0;
    border-bottom: 1px solid var(--border-color);
}

.message-title {
    font-size: 13px;
    font-weight: 600;
    color: var(--text-muted);
}

.copy-button {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px 12px;
    background-color: #fff;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-main);
    font-size: 13px;
    font-weight: 500;
    font-family: inherit;
    cursor: pointer;
    transition: var(--transition);
}

.copy-button:hover {
    background-color: #f8fafc;
    border-color: #cbd5e1;
    color: var(--primary-color);
}

.copy-button:active {
    transform: scale(0.97);
}

.message-body {
    padding: 16px;
    font-size: 14px;
    color: var(--text-main);
    line-height: 1.6;
    background-color: #fff;
    white-space: pre-wrap;
}

/* Toast Notification */
.toast {
    position: fixed;
    bottom: 24px;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background-color: var(--text-main);
    color: white;
    padding: 12px 24px;
    border-radius: 30px;
    font-size: 14px;
    font-weight: 500;
    opacity: 0;
    transition: all 0.3s cubic-bezier(0.68, -0.55, 0.265, 1.55);
    z-index: 1000;
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

.toast.show {
    transform: translateX(-50%) translateY(0);
    opacity: 1;
}

/* Responsive adjustments */
@media (max-width: 480px) {
    .calculator-card {
        padding: 24px 20px;
    }
    
    .radio-group.frequency-group {
        grid-template-columns: repeat(4, 1fr);
    }
    
    .deadline-date {
        font-size: 24px;
    }
}