:root {
    --color-work: #e74c3c;
    --color-break: #27ae60;
    --color-long-break: #8e44ad;
    --color-gray: #95a5a6;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: Arial, sans-serif;
    background-color: #f5f5f5;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

main {
    width: 100%;
}

.container {
    position: relative;
    text-align: center;
    background: white;
    padding: 50px;
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    max-width: 500px;
    margin: auto;
}

h1 {
    font-size: 32px;
    margin-bottom: 30px;
    color: #333;
}

.timer {
    font-size: 60px;
    font-weight: bold;
    color: var(--color-work);
    margin: 0;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

.actions {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 10px;
}

.actions button {
    background-color: var(--color-work);
    padding: 15px 40px;
    border-radius: 10px;
    border: none;
    outline: none;
    cursor: pointer;
    color: #fff;
    font-size: 16px;
    font-weight: 600;
    transition: opacity 0.2s, transform 0.1s;
}

.actions button:hover:not(:disabled) {
    opacity: 0.9;
    transform: translateY(-1px);
}

.actions button:active:not(:disabled) {
    transform: translateY(0);
}

.actions button:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.mode {
    font-size: 24px;
    font-weight: bold;
    color: var(--color-work);
    margin-bottom: 20px;
    text-transform: uppercase;
    letter-spacing: 2px;
}

.session {
    font-size: 18px;
    color: #7f8c8d;
    margin-bottom: 10px;
    font-weight: 600;
}

.keyboard-hint {
    margin-top: 20px;
    font-size: 12px;
    color: #bdc3c7;
    letter-spacing: 0.5px;
}

.mute-btn {
    position: absolute;
    top: 20px;
    right: 20px;
    background: transparent;
    border: 2px solid var(--color-gray);
    color: var(--color-gray);
    padding: 8px 16px;
    font-size: 14px;
    cursor: pointer;
    border-radius: 20px;
    transition: background 0.2s, color 0.2s, border-color 0.2s;
}

.mute-btn:hover {
    background: #ecf0f1;
}

.mute-btn:focus-visible {
    outline: 2px solid #3498db;
    outline-offset: 2px;
}

.mute-btn.muted {
    color: var(--color-work);
    border-color: var(--color-work);
}

.timer-container {
    position: relative;
    width: 300px;
    height: 300px;
    margin: 30px auto;
}

.progress-ring {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    transform: rotate(-90deg);
}

.progress-ring-circle {
    transition: stroke-dashoffset 1s linear;
    stroke-linecap: round;
}

#pauseButton {
    background-color: #f39c12;
}

#pauseButton:hover:not(:disabled) {
    background-color: #e67e22;
}

#resetButton {
    background-color: var(--color-gray);
}

#resetButton:hover:not(:disabled) {
    background-color: #7f8c8d;
}

/* Focus visible for keyboard navigation */
.actions button:focus-visible,
.settings-btn:focus-visible {
    outline: 2px solid #3498db;
    outline-offset: 2px;
}

/* Mode Color Classes */
.mode-work .mode,
.mode-work .timer {
    color: var(--color-work);
}

.mode-work .progress-ring-circle {
    stroke: var(--color-work);
}

.mode-break .mode,
.mode-break .timer {
    color: var(--color-break);
}

.mode-break .progress-ring-circle {
    stroke: var(--color-break);
}

.mode-long-break .mode,
.mode-long-break .timer {
    color: var(--color-long-break);
}

.mode-long-break .progress-ring-circle {
    stroke: var(--color-long-break);
}

/* Settings Button */
.settings-btn {
    position: absolute;
    top: 20px;
    left: 20px;
    background: transparent;
    border: 2px solid var(--color-gray);
    color: var(--color-gray);
    font-size: 24px;
    width: 45px;
    height: 45px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s;
}

.settings-btn:hover {
    background: #ecf0f1;
    transform: rotate(90deg);
}

/* Settings Panel */
.settings-panel {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    transition: opacity 0.3s;
}

.settings-panel.hidden {
    display: none;
}

.settings-content {
    background: white;
    padding: 40px;
    border-radius: 15px;
    width: 90%;
    max-width: 400px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.3);
}

.settings-content h2 {
    margin-bottom: 30px;
    color: #2c3e50;
    text-align: center;
}

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

.setting-group label {
    display: block;
    margin-bottom: 8px;
    color: #34495e;
    font-weight: 600;
}

.setting-group input {
    width: 100%;
    padding: 12px;
    border: 2px solid #ecf0f1;
    border-radius: 8px;
    font-size: 16px;
    transition: border 0.3s;
}

.setting-group input:focus {
    outline: none;
    border-color: #3498db;
}

.settings-buttons {
    display: flex;
    gap: 10px;
    margin-top: 30px;
}

.settings-buttons button {
    flex: 1;
    padding: 12px;
    font-size: 16px;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s;
}

.settings-buttons button:focus-visible {
    outline: 2px solid #3498db;
    outline-offset: 2px;
}

.btn-primary {
    background: var(--color-break);
    color: white;
}

.btn-primary:hover {
    background: #229954;
}

.btn-secondary {
    background: var(--color-gray);
    color: white;
}

.btn-secondary:hover {
    background: #7f8c8d;
}

/* Toast Notifications */
.toast-container {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 2000;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.toast {
    padding: 14px 24px;
    border-radius: 10px;
    color: white;
    font-size: 14px;
    font-weight: 600;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
    animation: toastIn 0.3s ease, toastOut 0.3s ease 2.7s forwards;
    max-width: 320px;
}

.toast-success {
    background: var(--color-break);
}

.toast-error {
    background: var(--color-work);
}

.toast-info {
    background: #3498db;
}

@keyframes toastIn {
    from {
        transform: translateX(100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

@keyframes toastOut {
    from {
        opacity: 1;
    }
    to {
        opacity: 0;
    }
}

/* Responsive Design */
@media (max-width: 520px) {
    .container {
        padding: 40px 20px 30px;
        border-radius: 15px;
        margin: 10px;
    }

    h1 {
        font-size: 26px;
        margin-bottom: 20px;
    }

    .timer-container {
        width: 240px;
        height: 240px;
        margin: 20px auto;
    }

    .timer {
        font-size: 48px;
    }

    .mode {
        font-size: 20px;
        margin-bottom: 15px;
    }

    .session {
        font-size: 16px;
    }

    .actions button {
        padding: 12px 28px;
        font-size: 14px;
    }

    .mute-btn {
        top: 12px;
        right: 12px;
        padding: 6px 12px;
        font-size: 12px;
    }

    .settings-btn {
        top: 12px;
        left: 12px;
        width: 38px;
        height: 38px;
        font-size: 20px;
    }

    .keyboard-hint {
        display: none;
    }

    .toast {
        max-width: 260px;
        font-size: 13px;
        padding: 12px 18px;
    }

    .toast-container {
        top: 10px;
        right: 10px;
    }
}

@media (max-width: 380px) {
    .container {
        padding: 35px 15px 25px;
    }

    h1 {
        font-size: 22px;
    }

    .timer-container {
        width: 200px;
        height: 200px;
    }

    .timer {
        font-size: 40px;
    }

    .mode {
        font-size: 18px;
    }

    .actions {
        flex-wrap: wrap;
        justify-content: center;
    }

    .actions button {
        padding: 10px 24px;
    }

    .settings-content {
        padding: 25px;
    }
}

/* Reduced Motion */
@media (prefers-reduced-motion: reduce) {
    .progress-ring-circle {
        transition: none;
    }

    .toast {
        animation: none;
    }

    .settings-btn {
        transition: none;
    }

    .settings-btn:hover {
        transform: none;
    }

    .actions button {
        transition: none;
    }
}