:root {
    --font-family: 'SF Mono', 'Monaco', 'Inconsolata', 'Fira Code', 'Droid Sans Mono', 'Source Code Pro', 'Consolas', 'Roboto Mono', 'Courier New', monospace;
    --bg-primary: #ede7dc;
    --bg-secondary: #ffffff;
    --bg-tertiary: #f5f2ed;
    --text-primary: #1c1917;
    --text-secondary: #44403c;
    --text-muted: #78716c;
    --text-settlements: #c2410c;
    --text-expenses: #16a34a;
    --text-success: #ffffff;
    --bg-success: #16a34a;
    --shadow-success: rgba(22, 163, 74, 0.3);
    --bg-button-primary: #16a34a;
    --bg-button-primary-hover: #22c55e;
    --text-button-primary: #ffffff;
    --bg-button-secondary: rgba(0, 0, 0, 0.1);
    --bg-button-secondary-hover: rgba(0, 0, 0, 0.2);
    --text-button-secondary: #1c1917;
    --bg-button-settle: #c2410c;
    --bg-button-settle-hover: #ea580c;
    --text-button-settle: #ffffff;
    --bg-settlement-success: #c2410c;
    --text-settlement-success: #ffffff;
    --border-primary: #ede7dc;
    --border-focus: #16a34a;
    --border-expenses: #16a34a;
    --border-settlements: #f97316;
    --bg-error: #fee;
    --text-error: #c53030;
    --border-error: #fc8181;
    --bg-warning: rgba(50,50,50,0.5);
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg-primary: #0c0a09;
        --bg-secondary: #1c1917;
        --bg-tertiary: #292524;
        --text-primary: #fafaf9;
        --text-secondary: #d6d3d1;
        --text-muted: #a8a29e;
        --text-settlements: #f97316;
        --text-expenses: #16a34a;
        --text-success: #000000;
        --bg-success: #22c55e;
        --shadow-success: rgba(34, 197, 94, 0.3);
        --bg-button-primary: #22c55e;
        --bg-button-primary-hover: #86efac;
        --text-button-primary: #000000;
        --bg-button-secondary: rgba(255, 255, 255, 0.2);
        --bg-button-secondary-hover: rgba(255, 255, 255, 0.5);
        --text-button-secondary: #fafaf9;
        --bg-button-settle: #f97316;
        --bg-button-settle-hover: #fb923c;
        --text-button-settle: #000000;
        --bg-settlement-success: #f97316;
        --text-settlement-success: #000000;
        --border-primary: #44403c;
        --border-focus: #22c55e;
        --border-expenses: #16a34a;
        --border-settlements: #f97316;
        --bg-error: #2d1b1b;
        --text-error: #fc8181;
        --border-error: #c53030;
        --bg-warning: rgba(50,50,50,0.5);
    }
}

body {
    font-family: var(--font-family);
    font-size: 14px;
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
    padding-bottom: 150px;
    background: var(--bg-primary);
    line-height: 1.6;
    color: var(--text-primary);
    transition: background-color 0.2s, color 0.2s;
}

h1 {
    text-align: center;
    color: var(--text-primary);
    margin-bottom: 30px;
    font-weight: 600;
}

h2 {
    color: var(--text-primary);
    font-size: 1.2rem;
    font-weight: 500;
    margin-top: 0;
    margin-bottom: 10px;
}

pre {
    background: var(--bg-secondary);
    padding: 4px 6px;
    border-radius: 4px;
    font-family: var(--font-family);
    color: var(--text-primary);
    display: block;
    margin: 0;
}

textarea {
    width: 100%;
    min-height: 150px;
    max-height: 60vh;
    padding: 15px;
    border: 2px solid var(--border-primary);
    border-radius: 8px;
    font-family: var(--font-family);
    font-size: 16px;
    resize: none;
    box-sizing: border-box;
    background: var(--bg-secondary);
    color: var(--text-primary);
    transition: border-color 0.2s, background-color 0.2s, color 0.2s;
    overflow-y: auto;
    white-space: pre;
    overflow-x: auto;
}

textarea:focus {
    outline: none;
    border-color: var(--border-focus);
}

.results {
    margin-top: 20px;
    border-radius: 8px;
    border: 0;
    overflow: hidden;
    transition: background-color 0.2s, border-color 0.2s;
    text-wrap: balance;
}

.summary {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0;
    padding: 10px 16px;
    color: var(--text-primary);
    background: var(--bg-tertiary);
    border-left: 4px solid var(--border-primary);
    transition: background-color 0.2s;
    flex-wrap: wrap;
    gap: 8px;
    width: 100%;
    box-sizing: border-box;
    border-bottom: 1px solid var(--border-primary);
}

.summary:last-of-type {
    border-bottom: none;
}

.summary .label {
    flex: 2 1 auto;
    white-space: balance;
}

.summary .total {
    text-align: right;
    line-height: 1.3;
}

.expenses-summary {
    border-left: 4px solid var(--border-expenses);
}

.settlements-summary {
    border-left: 4px solid var(--border-settlements);
}
.settlements-summary .label {
    margin-right: 8px;
}

.expenses-total {
    color: var(--text-expenses);
}
.settlements-total {
    color: var(--text-settlements);
}

.expenses-total, .settlements-total {
    font-size: 1.1rem;
    font-weight: bold;
}

button {
    font-family: var(--font-family);
    font-size: 16px;
    background: var(--bg-button-primary);
    color: var(--text-button-primary);
    border: none;
    font-weight: bold;
    cursor: pointer;
    transition: all 0.2s;
    white-space: nowrap;
}

button:hover {
    background: var(--bg-button-primary-hover);
    transform: translateY(-1px);
}

button:active {
    transform: translateY(0);
}

.actions {
    margin: 40px 0;
    display: flex;
    gap: 15px;
    justify-content: center;
}

.copy-button {
    padding: 12px 24px;
    border-radius: 8px;
    flex: 1;
    max-width: 200px;
}

.reset-button {
    padding: 12px 24px;
    border-radius: 8px;
    flex: 1;
    max-width: 200px;
    background: var(--bg-button-secondary);
    color: var(--text-button-secondary);
    border: 1px solid var(--border-primary);
}

.reset-button:hover {
    background: var(--bg-button-secondary-hover);
}

.reset-button:active {
    background: var(--bg-button-secondary-hover);
}

.copy-button.copied {
    background: var(--bg-success);
    color: var(--text-success);
}

.settle-button {
    padding: 6px 12px;
    border-radius: 4px;
    background: var(--bg-button-settle);
    color: var(--text-button-settle);
}

.settle-button:hover {
    background: var(--bg-button-settle-hover);
}

.settlements-summary.settlement-success {
    background: var(--bg-settlement-success);
    color: var(--text-settlement-success);
    transform: scale(1.02);
    box-shadow: 0 2px 8px rgba(194, 65, 12, 0.4);
}

@media (prefers-color-scheme: dark) {
    .settlements-summary.settlement-success {
        box-shadow: 0 2px 8px rgba(249, 115, 22, 0.4);
    }
}

.settlements-summary.settlement-success .label {
    color: var(--text-settlement-success);
    text-align: center;
    font-weight: bold;
}

.settlements-summary.settlement-success .settle-button {
    background: var(--bg-button-secondary-hover);
    color: var(--text-settlement-success);
    cursor: default;
}

.settlements-summary.all-settled-up {
    color: var(--text-muted);
    font-style: italic;
}

.settlements-summary.settlement-log {
    color: var(--text-muted);
    opacity: 0.7;
}

.validation-warning {
    background: var(--bg-error);
    color: var(--text-error);
    border: 1px solid var(--border-error);
    border-radius: 8px;
    padding: 12px;
    margin: 10px 0;
    line-height: 1.4;
}

.validation-warning .warning-line {
    background: var(--bg-warning);
    padding: 10px 16px;
    border-radius: 4px;
    margin: 8px 0;
    font-family: monospace;
}

/* Slide animations */
@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-15px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* CSS Custom Properties for animation timing */
:root {
    --stagger-delay: 50ms;
    --base-delay: 0ms;
    --section-gap: 100ms;
}

/* Base animation for all summary items */
.summary {
    opacity: 0;
    transform: translateY(-15px);
    animation: slideDown 0.3s ease-out forwards;
    /* Default delay calculation: base + (index * stagger) */
    animation-delay: calc(var(--base-delay) + var(--stagger-delay) * var(--index, 0));
}

/* Expenses section - starts immediately */
#expenses-results {
    --base-delay: 0ms;
}

/* Settlements section - starts after expenses with gap */
#settlements-results {
    --base-delay: var(--section-gap);
}

/* For items that shouldn't animate on updates */
.summary.no-animate {
    opacity: 1;
    transform: translateY(0);
    animation: none;
}



.slide-in {
    opacity: 0;
    transform: translateY(-15px);
    animation: slideDown 0.3s ease-out forwards;
}

.help-section, .example-section {
    margin: 20px 0;
}

.format-guide {
    background: var(--bg-tertiary);
    border-radius: 8px;
    border-left: 4px solid var(--border-primary);
    padding: 20px;
}

.format-item {
    display: grid;
    grid-template-columns: 1fr 2fr 1.5fr;
    gap: 16px;
    padding: 12px 0;
    border-bottom: 1px solid var(--border-primary);
    align-items: start;
}

.format-item:last-child {
    border-bottom: none;
}

.format-name {
    font-weight: 600;
    color: var(--text-primary);
    font-family: var(--font-family);
}

.format-description {
    color: var(--text-secondary);
    font-family: var(--font-family);
}

.format-example {
    font-family: var(--font-family);
}

.example-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
}

.example {
    padding: 20px;
    background: var(--bg-tertiary);
    border-radius: 8px;
    border-left: 4px solid var(--border-primary);
}

.example pre {
    padding: 10px;
}

@media (max-width: 768px) {
    .settle-text {
        display: none;
    }

    .actions {
        flex-direction: column;
    }

    .copy-button,
    .reset-button {
        max-width: none;
        width: 100%;
    }

    .format-guide {
        padding: 15px;
    }

    .format-item {
        grid-template-columns: 1fr;
        gap: 0;
        padding: 16px 0;
    }

    .format-name {
        font-size: 1.1em;
        margin-bottom: 2px;
    }

    .format-description {
        font-size: 0.95em;
        margin-bottom: 8px;
    }

    .format-example {
        font-size: 0.9em;
    }

}