:root {
    --bg-color: #f4f6f9;
    --card-bg: #ffffff;
    --text-main: #2b3440;
    --text-muted: #6b7280;
    --primary: #2563eb;
    --primary-hover: #1d4ed8;
    --danger: #ef4444;
    --danger-hover: #dc2626;
    --border-color: #e5e7eb;
    --radius: 8px;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

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

body {
    background-color: var(--bg-color);
    color: var(--text-main);
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    line-height: 1.6;
    padding: 40px 20px;
}

.container {
    max-width: 900px;
    margin: 0 auto;
}

header {
    text-align: center;
    margin-bottom: 40px;
}

h1 {
    color: var(--text-main);
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 8px;
    letter-spacing: -0.025em;
}

p.subtitle {
    color: var(--text-muted);
    font-size: 1.1rem;
}

.card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 24px;
    box-shadow: var(--shadow-sm);
    margin-bottom: 30px;
}

.card-header {
    margin-bottom: 20px;
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-main);
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 12px;
}

.input-group {
    margin-bottom: 20px;
}

label {
    display: block;
    margin-bottom: 6px;
    color: var(--text-main);
    font-weight: 500;
    font-size: 0.9rem;
}

input, textarea {
    width: 100%;
    padding: 10px 12px;
    background: #ffffff;
    border: 1px solid var(--border-color);
    color: var(--text-main);
    font-family: inherit;
    border-radius: 6px;
    font-size: 0.95rem;
    transition: border-color 0.2s, box-shadow 0.2s;
}

input:focus, textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}

.btn {
    display: inline-block;
    background: var(--primary);
    color: #ffffff;
    border: 1px solid var(--primary);
    padding: 10px 20px;
    font-family: inherit;
    font-weight: 500;
    font-size: 0.95rem;
    border-radius: 6px;
    cursor: pointer;
    text-align: center;
    transition: background-color 0.2s, color 0.2s, border-color 0.2s;
    width: 100%;
}

.btn:hover {
    background: var(--primary-hover);
    border-color: var(--primary-hover);
}

.btn-outline {
    background: transparent;
    color: var(--primary);
    border-color: var(--primary);
}

.btn-outline:hover {
    background: var(--primary);
    color: #ffffff;
}

.btn-danger {
    background: transparent;
    color: var(--danger);
    border-color: var(--danger);
}

.btn-danger:hover {
    background: var(--danger);
    color: #ffffff;
    border-color: var(--danger);
}


.grid-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 24px;
}


.capsule-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 20px;
    box-shadow: var(--shadow-sm);
    transition: box-shadow 0.2s, transform 0.2s;
    display: flex;
    flex-direction: column;
}

.capsule-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.capsule-card.locked {
    border-top: 4px solid var(--text-muted);
}

.capsule-card:not(.locked) {
    border-top: 4px solid var(--primary);
}

.capsule-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 12px;
}

.capsule-title {
    font-weight: 600;
    font-size: 1.1rem;
    color: var(--text-main);
    margin-top: 4px;
}

.status-badge {
    display: inline-block;
    padding: 4px 8px;
    border-radius: 12px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.status-badge.locked {
    background-color: #f3f4f6;
    color: var(--text-muted);
}

.status-badge.unlocked {
    background-color: #eff6ff;
    color: var(--primary);
}

.status-icon {
    font-size: 1.2rem;
    margin-left: 8px;
}

.capsule-date {
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-bottom: 16px;
    line-height: 1.4;
}

.capsule-message {
    background: #f9fafb;
    padding: 16px;
    border-radius: 6px;
    margin-bottom: 16px;
    flex-grow: 1;
    font-size: 0.95rem;
    color: var(--text-main);
    white-space: pre-wrap;
    word-wrap: break-word;
    border: 1px solid var(--border-color);
}

.locked .capsule-message {
    background: #f3f4f6;
    color: var(--text-muted);
    text-align: center;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    font-weight: 500;
}

.card-actions {
    display: flex;
    gap: 12px;
    margin-top: auto;
}

.card-actions button {
    flex: 1;
    padding: 8px 12px;
    font-size: 0.85rem;
}


.modal {
    display: none; 
    position: fixed;
    z-index: 100;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(17, 24, 39, 0.4);
    backdrop-filter: blur(4px);
}

.modal-content {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    margin: 10% auto;
    width: 90%;
    max-width: 500px;
    padding: 24px;
    position: relative;
    box-shadow: var(--shadow-lg);
}

.close-btn {
    color: var(--text-muted);
    position: absolute;
    right: 20px;
    top: 15px;
    font-size: 24px;
    line-height: 1;
    cursor: pointer;
    transition: color 0.2s;
}

.close-btn:hover {
    color: var(--text-main);
}